Kenso Soai

Reversal of the sense of enantioselectivity between 1- and 2-aza[6]helicenes used as chiral inducers of asymmetric autocatalysis

Co-reporter:Arimasa Matsumoto;Kento Yonemitsu;Hanae Ozaki;Jiří Míšek;Ivo Starý;Irena G. Stará

Organic & Biomolecular Chemistry 2017 vol. 15(Issue 6) pp:1321-1324

Publication Date(Web):2017/02/07

DOI:10.1039/C6OB02745H

Reversal of the sense of enantioselectivity was observed between 1-aza[6]helicene 2 and 2-aza[6]helicene 3 employed as chiral inducers of asymmetric autocatalysis of pyrimidyl alkanol. In the presence of (P)-(+)-1-aza[6]helicene 2, the reaction of pyrimidine-5-carbaldehyde 1 with diisopropylzinc afforded, in conjunction with asymmetric autocatalysis, (S)-pyrimidyl alkanol 4 with high ee. Surprisingly, the reaction in the presence of (P)-(+)-2-aza[6]helicene 3 gave the opposite enantiomer of (R)-alkanol 4 with high ee. In the same manner, (M)-(−)-2 and (M)-(−)-3 afforded (R)- and (S)-alkanol 4, respectively. The sense of enantioselectivity is controlled not only by the helicity of the azahelicene derivatives but also by the position of the nitrogen atom.

Unusual reversal of enantioselectivity in the asymmetric autocatalysis of pyrimidyl alkanol triggered by chiral aromatic alkanols and amines

Co-reporter:Arimasa Matusmoto;Satoshi Fujiwara;Yui Hiyoshi;Kerstin Zawatzky;Alexey A. Makarov;Christopher J. Welch

Organic & Biomolecular Chemistry 2017 vol. 15(Issue 3) pp:555-558

Publication Date(Web):2017/01/18

DOI:10.1039/C6OB02415G

Temperature dependent inversion of enantioselectivity in asymmetric catalysis is an interesting and somewhat unusual phenomenon. We have observed temperature dependent inversion of enantioselectivity in the asymmetric autocatalysis reaction when triggered by a wide scope of enantioenriched alcohols and amines. The addition reaction of diisopropylzinc to pyrimidine-5-carbaldehyde in the presence of enantiopure alcohols or amines affords the pyrimidyl alkanol product at 0 °C with high ee. However, lowering the reaction temperature to −44 °C affords the opposite enantioselectivity.

Can the analyte-triggered asymmetric autocatalytic Soai reaction serve as a universal analytical tool for measuring enantiopurity and assigning absolute configuration?

Co-reporter:Christopher J. Welch;Kerstin Zawatzky;Alexey A. Makarov;Satoshi Fujiwara;Arimasa Matsumoto

Organic & Biomolecular Chemistry 2017 vol. 15(Issue 1) pp:96-101

Publication Date(Web):2016/12/20

DOI:10.1039/C6OB01939K

An investigation is reported on the use of the autocatalytic enantioselective Soai reaction, known to be influenced by the presence of a wide variety of chiral materials, as a generic tool for measuring the enantiopurity and absolute configuration of any substance. Good generality for the reaction across a small group of test analytes was observed, consistent with literature reports suggesting a diversity of compound types that can influence the stereochemical outcome of this reaction. Some trends in the absolute sense of stereochemical enrichment were noted, suggesting the possible utility of the approach for assigning absolute configuration to unknown compounds, by analogy to closely related species with known outcomes. Considerable variation was observed in the triggering strength of different enantiopure materials, an undesirable characteristic when dealing with mixtures containing minor impurities with strong triggering strength in the presence of major components with weak triggering strength. A strong tendency of the reaction toward an ‘all or none’ type of behavior makes the reaction most sensitive for detecting enantioenrichment close to zero. Consequently, the ability to discern modest from excellent enantioselectivity was relatively poor. While these properties limit the ability to obtain precise enantiopurity measurements in a simple single addition experiment, prospects may exist for more complex experimental setups that may potentially offer improved performance.

Point-to-Point Ultra-Remote Asymmetric Control with Flexible Linker

Co-reporter: Dr. Tsuneomi Kawasaki;Yasuyuki Ishikawa;Yoshihiro Minato;Takashi Otsuka;Shigeru Yonekubo; Dr. Itaru Sato; Dr. Takanori Shibata;Dr. Arimasa Matsumoto; Dr. Kenso Soai

Chemistry - A European Journal 2017 Volume 23(Issue 2) pp:282-285

Publication Date(Web):2017/01/05

DOI:10.1002/chem.201605076

AbstractAn ultra-remote intramolecular (point-to-point) asymmetric control through 38 bonds (1,39-asymmetric induction) has been achieved by using the principle of direct supramolecular orientation of catalytic and reactive moieties in asymmetric autocatalysis. We found the highly stereoselective diisopropylzinc addition reaction using designed molecules possessing pyrimidine sites at each terminal of a conformationally flexible simple methylene chain.

Helical mesoporous silica as an inorganic heterogeneous chiral trigger for asymmetric autocatalysis with amplification of enantiomeric excess

Co-reporter:Tsuneomi Kawasaki, Yuko Araki, Kunihiko Hatase, Kenta Suzuki, Arimasa Matsumoto, Toshiyuki Yokoi, Yoshihiro Kubota, Takashi Tatsumi and Kenso Soai

Chemical Communications 2015 vol. 51(Issue 42) pp:8742-8744

Publication Date(Web):16 Mar 2015

DOI:10.1039/C5CC01750E

Mesoporous silica has been used as a heterogeneous support for catalysts; however, asymmetric induction by the helicity of inorganic mesoporous silica itself has not yet been achieved. P- and M-helical mesoporous silica was found to act as a chiral inorganic trigger for asymmetric autocatalysis to afford (S) and (R)-pyrimidyl alkanol with >99.5% ee, respectively.

Asymmetric induction by retgersite, nickel sulfate hexahydrate, in conjunction with asymmetric autocatalysis

Co-reporter:Arimasa Matsumoto, Hirokazu Ozawa, Ayako Inumaru and Kenso Soai

New Journal of Chemistry 2015 vol. 39(Issue 9) pp:6742-6745

Publication Date(Web):16 Jul 2015

DOI:10.1039/C5NJ01459J

Retgersite, nickel sulfate hexahydrate, forms a chiral crystal with space group P41212 or P43212. A chiral crystal of nickel sulfate hexahydrate was found to act as a chiral initiator of asymmetric autocatalysis, affording highly enantiomerically enriched pyrimidyl alkanols with the corresponding absolute configurations.

Crystal Structure of the Isopropylzinc Alkoxide of Pyrimidyl Alkanol: Mechanistic Insights for Asymmetric Autocatalysis with Amplification of Enantiomeric Excess

Co-reporter:Dr. Arimasa Matsumoto;Takaaki Abe;Atsushi Hara;Takayuki Tobita;Taisuke Sasagawa;Dr. Tsuneomi Kawasaki;Dr. Kenso Soai

Angewandte Chemie 2015 Volume 127( Issue 50) pp:15433-15436

Publication Date(Web):

DOI:10.1002/ange.201508036

Abstract

Asymmetric amplification during self-replication is a key feature that is used to explain the origin of homochirality. Asymmetric autocatalysis of pyrimidyl alkanol in the asymmetric addition of diisopropylzinc to pyrimidine-5-carbaldehyde is a unique example of this phenomenon. Crystallization of zinc alkoxides of this 5-pyrimidyl alkanol and single-crystal X-ray diffraction analysis of the alkoxide crystals reveal the existence of tetramer or higher oligomer structures in this asymmetric autocatalytic system.

Crystal Structure of the Isopropylzinc Alkoxide of Pyrimidyl Alkanol: Mechanistic Insights for Asymmetric Autocatalysis with Amplification of Enantiomeric Excess

Co-reporter:Dr. Arimasa Matsumoto;Takaaki Abe;Atsushi Hara;Takayuki Tobita;Taisuke Sasagawa;Dr. Tsuneomi Kawasaki;Dr. Kenso Soai

Angewandte Chemie International Edition 2015 Volume 54( Issue 50) pp:15218-15221

Publication Date(Web):

DOI:10.1002/anie.201508036

Abstract

Asymmetric amplification during self-replication is a key feature that is used to explain the origin of homochirality. Asymmetric autocatalysis of pyrimidyl alkanol in the asymmetric addition of diisopropylzinc to pyrimidine-5-carbaldehyde is a unique example of this phenomenon. Crystallization of zinc alkoxides of this 5-pyrimidyl alkanol and single-crystal X-ray diffraction analysis of the alkoxide crystals reveal the existence of tetramer or higher oligomer structures in this asymmetric autocatalytic system.

Asymmetric Autocatalysis of Pyrimidyl Alkanol and Its Application to the Study on the Origin of Homochirality

Co-reporter:Kenso Soai, Tsuneomi Kawasaki, and Arimasa Matsumoto

Accounts of Chemical Research 2014 Volume 47(Issue 12) pp:3643

Publication Date(Web):November 19, 2014

DOI:10.1021/ar5003208

ConspectusAmplification of enantiomeric excess (ee) is a key feature for the chemical evolution of biological homochirality from the origin of chirality. We describe the amplification of ee in the asymmetric autocatalysis of 5-pyrimidyl alkanols in the reaction between diisopropylzinc (i-Pr2Zn) and pyrimidine-5-carbaldehydes. During the reaction, an extremely low ee (ca. 0.00005% ee) can be amplified to >99.5% ee, and therefore, the initial slightly major enantiomer is automultiplied by a factor of ca. 630000, while the initial slightly minor enantiomer is automultiplied by a factor of less than 1000. In addition, pyrimidyl alkanols with various substituents at the 2-position of the pyrimidine ring, 3-quinolyl alkanol, 5-carbamoyl-3-pyridyl alkanol, and large multifunctionalized pyrimidyl alkanols also act as highly efficient asymmetric autocatalysts in the addition of i-Pr2Zn to the corresponding aldehydes.The asymmetric autocatalysis of pyrimidyl alkanol can discriminate the chirality of various compounds. Chiral substances such as alcohols, amino acids, hydrocarbons, metal complexes, and heterogeneous chiral materials can act as chiral triggers for asymmetric autocatalysis to afford pyrimidyl alkanols with the corresponding absolute configuration of the initiator. This recognition ability of chiral compounds is extremely high, and chiral discrimination of a cryptochiral quaternary saturated hydrocarbon was established by applying asymmetric autocatalysis.By using the large amplification effect of the asymmetric autocatalysis, we can link various proposed origins of chirality with highly enantioenriched organic compounds in conjunction with asymmetric autocatalysis. Thus, a statistical fluctuation in ee of racemic compounds can be amplified to high ee by using asymmetric autocatalysis. Enantiomeric imbalance induced by irradiation of circularly polarized light can affect the enantioselectivity of asymmetric autocatalysis. The asymmetric autocatalysis was also triggered by the morphology of inorganic chiral crystals such as quartz, sodium chlorate, and cinnabar. Chiral organic crystals of achiral compounds also act as chiral initiators, and during the study of a crystal of cytosine, enantioselective chiral crystal phase transformation of the cytosine crystal was achieved by removal of the water of crystallization in an achiral monohydrate crystal. Enantioselective C–C bond formation was realized on the surfaces of achiral single crystals based on the oriented prochirality of achiral aldehydes. Furthermore, asymmetric autocatalysis of pyrimidyl alkanols is a highly sensitive reaction that can recognize and amplify the significantly small effect of a chiral compound arising solely from isotope substitution of hydrogen, carbon, and oxygen (D/H, 13C/12C, and 18O/16O). These examples show that asymmetric autocatalysis with an amplification of chirality is a powerful tool for correlating the origin of chirality with highly enantioenriched organic compounds.Asymmetric autocatalysis using two β-amino alcohols reveals a reversal of enantioselectivity in the addition of i-Pr2Zn to aldehyde and is one approach toward understanding the mechanism of asymmetric dialkylzinc addition, where heteroaggregates act as the catalytic species.

Asymmetric Autocatalysis Initiated by Finite Single-Wall Carbon Nanotube Molecules with Helical Chirality

Co-reporter:Shunpei Hitosugi, Arimasa Matsumoto, Yoshiyasu Kaimori, Ryosuke Iizuka, Kenso Soai, and Hiroyuki Isobe

Organic Letters 2014 Volume 16(Issue 3) pp:645-647

Publication Date(Web):January 13, 2014

DOI:10.1021/ol403384q

An asymmetric autocatalysis reaction was initiated by a finite single-wall carbon nanotube molecule with helical chirality. The asymmetric induction was initiated by the chiral environment arising from the planar chirality of the tubular polyaromatic hydrocarbons.

Self-Replication and Amplification of Enantiomeric Excess of Chiral Multifunctionalized Large Molecules by Asymmetric Autocatalysis

Co-reporter:Dr. Tsuneomi Kawasaki;Mai Nakaoda;Yutaro Takahashi;Yusuke Kanto;Nanako Kuruhara;Kenji Hosoi;Dr. Itaru Sato;Arimasa Matsumoto ;Dr. Kenso Soai

Angewandte Chemie International Edition 2014 Volume 53( Issue 42) pp:11199-11202

Publication Date(Web):

DOI:10.1002/anie.201405441

Abstract

Self-replication of large chiral molecular architectures is one of the great challenges and interests in synthetic, systems, and prebiotic chemistry. Described herein is a new chemical system in which large chiral multifunctionalized molecules possess asymmetric autocatalytic self-replicating and self-improving abilities, that is, improvement of their enantioenrichment in addition to the diastereomeric ratio. The large chiral multifunctionalized molecules catalyze the production of themselves with the same structure, including the chirality of newly formed asymmetric carbon atoms, in the reaction of the corresponding achiral aldehydes and reagent. The chirality of the large multifunctionalized molecules controlled the enantioselectivity of the reaction in a highly selective manner to construct multiple asymmetric stereogenic centers in a single reaction.

The Origins of Homochirality Examined by Using Asymmetric Autocatalysis

Co-reporter:Kenso Soai;Tsuneomi Kawasaki;Arimasa Matsumoto

The Chemical Record 2014 Volume 14( Issue 1) pp:70-83

Publication Date(Web):

DOI:10.1002/tcr.201300028

Abstract

Pyrimidyl alkanol was found to act as an asymmetric autocatalyst in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde. Asymmetric autocatalysis of 2-alkynylpyrimidyl alkanol with an extremely low enantiomeric excess (ca. 0.00005% ee) exhibits enormous asymmetric amplification to afford the same compound with >99.5% ee. This asymmetric autocatalysis with amplification of ee has been employed to examine the validity of proposed theories of the origins of homochirality. Circularly polarized light, quartz, sodium chlorate, cinnabar, chiral organic crystals and spontaneous absolute asymmetric synthesis were considered as possible candidates for the origin of chirality; each could act as a chiral source in asymmetric autocatalysis. Asymmetric autocatalysis can discriminate the isotope chirality arising from the small difference between carbon (carbon-13/carbon-12) and hydrogen (D/H) isotopes. Cryptochiral compounds were also discriminated by asymmetric autocatalysis.

Self-Replication and Amplification of Enantiomeric Excess of Chiral Multifunctionalized Large Molecules by Asymmetric Autocatalysis

Co-reporter:Dr. Tsuneomi Kawasaki;Mai Nakaoda;Yutaro Takahashi;Yusuke Kanto;Nanako Kuruhara;Kenji Hosoi;Dr. Itaru Sato;Arimasa Matsumoto ;Dr. Kenso Soai

Angewandte Chemie 2014 Volume 126( Issue 42) pp:11381-11384

Publication Date(Web):

DOI:10.1002/ange.201405441

Abstract

Self-replication of large chiral molecular architectures is one of the great challenges and interests in synthetic, systems, and prebiotic chemistry. Described herein is a new chemical system in which large chiral multifunctionalized molecules possess asymmetric autocatalytic self-replicating and self-improving abilities, that is, improvement of their enantioenrichment in addition to the diastereomeric ratio. The large chiral multifunctionalized molecules catalyze the production of themselves with the same structure, including the chirality of newly formed asymmetric carbon atoms, in the reaction of the corresponding achiral aldehydes and reagent. The chirality of the large multifunctionalized molecules controlled the enantioselectivity of the reaction in a highly selective manner to construct multiple asymmetric stereogenic centers in a single reaction.

Asymmetric autocatalysis triggered by oxygen isotopically chiral glycerin

Co-reporter:Arimasa Matsumoto, Shotaro Oji, Shizuka Takano, Kyohei Tada, Tsuneomi Kawasaki and Kenso Soai

Organic & Biomolecular Chemistry 2013 vol. 11(Issue 18) pp:2928-2931

Publication Date(Web):05 Mar 2013

DOI:10.1039/C3OB40293B

Chiral (S)- and (R)-18O-glycerin induces enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, and the subsequent asymmetric autocatalysis affords (R)- and (S)-pyrimidyl alkanol with high enantiomeric excess, respectively.

Asymmetric Autocatalysis Induced by Cinnabar: Observation of the Enantioselective Adsorption of a 5-Pyrimidyl Alkanol on the Crystal Surface

Co-reporter:Dr. Hitoshi Shindo;Yusuke Shirota;Kaori Niki;Dr. Tsuneomi Kawasaki;Dr. Kenta Suzuki;Yuko Araki;Dr. Arimasa Matsumoto;Dr. Kenso Soai

Angewandte Chemie International Edition 2013 Volume 52( Issue 35) pp:9135-9138

Publication Date(Web):

DOI:10.1002/anie.201304284

Enantiodivergent formation of a chiral cytosine crystal by removal of crystal water from an achiral monohydrate crystal under reduced pressure

Co-reporter:Hiroko Mineki, Yoshiyasu Kaimori, Tsuneomi Kawasaki, Arimasa Matsumoto, Kenso Soai

Tetrahedron: Asymmetry 2013 Volume 24(21–22) pp:1365-1367

Publication Date(Web):30 November 2013

DOI:10.1016/j.tetasy.2013.09.020

An achiral nucleobase cytosine forms an achiral monohydrate crystal (space group: P21/c) by crystallization from a water solution. It was found that the removal of crystal water under reduced pressure at room temperature afforded a chiral crystal of anhydrous cytosine (P212121). The crystal chirality of anhydrous cytosine corresponds to the enantiotopic crystal face of the achiral monohydrate; therefore, when the enantiotopic b1-face is exposed to the reduced pressure, dehydration occurred in the direction from the b1-face to provide [CD(+)310KBr]-cytosine crystal. In contrast, dehydration from the b2-face gave the opposite enantiomorphous [CD(−)310KBr]-cytosine crystal. The correlation between enantiotopic faces and the formed crystal chirality is opposite to that from dehydration by heating. The formed chiral cytosine crystals act as a chiral trigger for asymmetric autocatalysis with enantioenrichment amplification of pyrimidylalkanol.

Asymmetric autocatalysis initiated by achiral nucleic acid base adenine: implications on the origin of homochirality of biomolecules

Co-reporter:Hiroko Mineki, Taichi Hanasaki, Arimasa Matsumoto, Tsuneomi Kawasaki and Kenso Soai

Chemical Communications 2012 vol. 48(Issue 85) pp:10538-10540

Publication Date(Web):31 Aug 2012

DOI:10.1039/C2CC34928K

Enantiomorphous crystals of adeninium dinitrate acted as the source of chirality in asymmetric autocatalysis producing highly enantioenriched (S)- and (R)-5-pyrimidyl alkanols, with the absolute configurations corresponding to that of crystals.

Asymmetric Autocatalysis Triggered by Chiral Crystals Formed from Achiral Compounds and Chiral Isotopomers

Co-reporter:Tsuneomi Kawasaki

Israel Journal of Chemistry 2012 Volume 52( Issue 7) pp:582-590

Publication Date(Web):

DOI:10.1002/ijch.201100155

Abstract

Asymmetric autocatalysis with amplification of enantiomeric excess is found in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde using pyrimidyl alkanol as an asymmetric autocatalyst. Asymmetric autocatalysis has been employed as a method for clarifying the origin of homochirality. Circularly polarized light, inorganic chiral crystals and statistical fluctuation of enantiomeric imbalance act as chiral initiators in asymmetric autocatalysis to afford highly enantioenriched products. We have investigated asymmetric autocatalysis using chiral crystals formed from achiral and racemic compounds as an origin of chirality. Absolute control of the crystal chirality of cytosine was achieved by the removal of crystal water. Enantioselective carbon-carbon bond formation at the enantiotopic crystal face of aldehydes was established using diisopropylzinc vapor. In addition, asymmetric autocatalysis triggered by chiral compounds arising from H, C and O isotope substitution has been achieved.

Enantioselective Synthesis Induced by Chiral Crystal Composed of dl-Serine in Conjunction with Asymmetric Autocatalysis

Co-reporter:Tsuneomi Kawasaki, Taisuke Sasagawa, Kazuya Shiozawa, Mizuki Uchida, Kenta Suzuki, and Kenso Soai

Organic Letters 2011 Volume 13(Issue 9) pp:2361-2363

Publication Date(Web):March 24, 2011

DOI:10.1021/ol200616t

Asymmetric autocatalysis initiated by chiral crystals containing racemic dl-serine was achieved. P- and M-crystals of dl-serine acted as the source of chirality of asymmetric autocatalysis to afford highly enantioenriched (>99.5% ee) (S)- and (R)-pyrimidylalkanols after the amplification of ee. This is the first example of the usage of the crystal, which contains the same number of d- and l-enantiomers as an origin of chirality in enantioselective synthesis.

A reversal phenomenon of enantioface selectivity by the cooperative operation of two chiral catalysts

Co-reporter:Tsuneomi Kawasaki, Yuki Wakushima, Mai Asahina, Kazuya Shiozawa, Tomoyuki Kinoshita, François Lutz and Kenso Soai

Chemical Communications 2011 vol. 47(Issue 18) pp:5277-5279

Publication Date(Web):22 Mar 2011

DOI:10.1039/C1CC10136F

The reversal phenomenon of enantioface selectivity in the asymmetric addition of diisopropylzinc to aldehydes was observed by mixing two chiral β-amino alcohol catalysts. The opposite enantiomeric product was formed on using a mixture of two chiral catalysts that possess individual enantioselectivity.

Asymmetric Autocatalysis: Triggered by Chiral Isotopomer Arising from Oxygen Isotope Substitution

Co-reporter:Dr. Tsuneomi Kawasaki;Yasushi Okano;Etsuharu Suzuki;Shizuka Takano;Shotaro Oji ;Dr. Kenso Soai

Angewandte Chemie International Edition 2011 Volume 50( Issue 35) pp:8131-8133

Publication Date(Web):

DOI:10.1002/anie.201102263

Enantioselective CC Bond Formation as a Result of the Oriented Prochirality of an Achiral Aldehyde at the Single-Crystal Face upon Treatment with a Dialkyl Zinc Vapor

Co-reporter:Dr. Tsuneomi Kawasaki;Sayaka Kamimura;Ai Amihara;Kenta Suzuki;Dr. Kenso Soai

Angewandte Chemie International Edition 2011 Volume 50( Issue 30) pp:6796-6798

Publication Date(Web):

DOI:10.1002/anie.201102031

Generation of Absolute Controlled Crystal Chirality by the Removal of Crystal Water from Achiral Crystal of Nucleobase Cytosine

Co-reporter:Tsuneomi Kawasaki ; Yuko Hakoda ; Hiroko Mineki ; Kenta Suzuki

Journal of the American Chemical Society 2010 Volume 132(Issue 9) pp:2874-2875

Publication Date(Web):February 12, 2010

DOI:10.1021/ja1000938

The enantioselective formation of chiral crystal of achiral nucleobase cytosine was achieved mediated by the crystal direction selective dehydration of crystal water in the achiral crystal of cytosine monohydrate (P21/c). Heat transfer from the enantiotopic face of the single crystal of cytosine monohydrate afforded the enantiomorphous crystal of anhydrous cytosine.

Amplification of chirality as a pathway to biological homochirality

Co-reporter:Tsuneomi Kawasaki, Kenso Soai

Journal of Fluorine Chemistry 2010 Volume 131(Issue 4) pp:525-534

Publication Date(Web):April 2010

DOI:10.1016/j.jfluchem.2009.12.014

Amplification of enantiomeric enrichment is a key feature for the chemical evolution of biological homochirality from the origin of chirality. The aggregations of the enantiomers by diastereomeric interactions enable the modification of their enantiomeric excess during some chemical processes. Fluorine-containing chiral compounds possess large amplification effect via distillation, sublimation and achiral chromatography by self-disproportionation. Asymmetric amplifications in enantioselective catalysis occur by the differential formation and reactivity between homochiral and heterochiral aggregate in solution.We described the amplification of ee in asymmetric autocatalysis of 5-pyrimidyl alkanol in the reaction between diisopropylzinc and pyrimidine-5-carbaldehdye. During the reactions extremely low ee (ca. 0.00005% ee) can be amplified to achieve more than 99.5% ee. Since the proposed origins of chirality such as CPL, quartz, chiral organic crystals of achiral compounds and statistical fluctuation of ee can initiate the asymmetric autocatalysis with amplification of ee, the proposed origin of chirality can be linked with enantiopure organic compound in conjunction with amplification of ee by asymmetric autocatalysis. In addition, we described that the carbon isotopically chiral compound triggers the asymmetric autocatalysis of 5-pyrimiodyl alkanol to afford the enantioenriched product with the absolute configuration correlated with that of carbon isotope chirality, that is, isotope chirality including hydrogen isotopes can control the enantioselectivity of asymmetric addition of alkyl metal reagent to aldehyde.Amplification of enantiomeric purity is key feature for the chemical evolution of biological homochirality. The diastereomeric interaction enables the modification of enantiomeric excess during some chemical processes. In asymmetric autocatalysis of 5-pyrimidyl alkanol, extremely low ee can be amplified to achieve almost enantiomerically pure chiral organic compound.

Asymmetric Autocatalysis Induced by Chiral Crystals of Achiral Tetraphenylethylenes

Co-reporter:Tsuneomi Kawasaki;Mai Nakaoda

Origins of Life and Evolution of Biospheres 2010 Volume 40( Issue 1) pp:

Publication Date(Web):2010 February

DOI:10.1007/s11084-009-9183-4

The achiral hydrocarbon tetraphenylethylene crystallizes in enantiomorphous forms (chiral space group: P21) to afford right- and left-handed hemihedral crystals, which can be recognized by solid-state circular dichroism spectroscopic analysis. Chiral organic crystals of tetraphenylethylene mediated enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde to give, in conjunction with asymmetric autocatalysis with amplification of chirality, almost enantiomerically pure (S)- and (R)-5-pyrimidyl alkanols whose absolute configurations were controlled efficiently by the crystalline chirality of the tetraphenylethylene substrate. Tetrakis(p-chlorophenyl)ethylene and tetrakis(p-bromophenyl)ethylene also show chirality in the crystalline state, which can also act as a chiral substrate and induce enantioselectivity of diisopropylzinc addition to pyrimidine-5-carbaldehyde in asymmetric autocatalysis to give enantiomerically enriched 5-pyrimidyl alkanols with the absolute configuration correlated with that of the chiral crystals. Highly enantioselective synthesis has been achieved using chiral crystals composed of achiral hydrocarbons, tetraphenylethylenes, as chiral inducers. This chemical system enables significant amplification of the amount of chirality using spontaneously formed chiral crystals of achiral organic compounds as the seed for the chirality of asymmetric autocatalysis.

Spontaneous absolute asymmetric synthesis promoted by achiral amines in conjunction with asymmetric autocatalysis

Co-reporter:Kenta Suzuki;Kunihiko Hatase;Daisuke Nishiyama

Journal of Systems Chemistry 2010 Volume 1( Issue 1) pp:

Publication Date(Web):2010 December

DOI:10.1186/1759-2208-1-5

The origin of homochirality of organic compounds such as L-amino acids and D-sugars have intrigued many scientists, and several hypotheses regarding its homochirality have been proposed. According to the statistical theory, small fluctuations in the ratio of the two enantiomers are present in a racemic mixture obtained from the reaction of achiral molecules.We report herein the reaction of pyrimidine-5-carbaldehyde and diisopropylzinc in the presence of achiral amine such as N,N'-dimethylpiperazine, N,N'-diethylpiperazine or N-methylmorpholine but in the absence of a chiral substance. The stochastic formation of (S)- and (R)-pyrimidyl alkanols with detectable ee was observed. This study shows that the slight fluctuation of the enantiomeric ratio of pyrimidyl alkanol produced at the initial reaction step can be enhanced significantly in conjunction with asymmetric autocatalysis with amplification of enantiomeric excess. We believe that the stochastic behavior in the formation of pyrimidyl alkanol constitutes one of the conditions necessary for spontaneous absolute asymmetric synthesis.

Asymmetric autocatalysis induced by meteoritic amino acids with hydrogen isotope chirality

Co-reporter:Tsuneomi Kawasaki, Masako Shimizu, Daisuke Nishiyama, Masateru Ito, Hitomi Ozawa and Kenso Soai

Chemical Communications 2009 (Issue 29) pp:4396-4398

Publication Date(Web):24 Jun 2009

DOI:10.1039/B908754K

Achiral meteoritic amino acids, glycine and α-methylalanine, with hydrogen isotope (D/H) chirality, acted as the source of chirality in asymmetric autocatalysis with amplification of ee to afford highly enantioenriched 5-pyrimidyl alkanols.

Discrimination of cryptochirality in chiral isotactic polystyrene by asymmetric autocatalysis

Co-reporter:Tsuneomi Kawasaki, Christiane Hohberger, Yuko Araki, Kunihiko Hatase, Klaus Beckerle, Jun Okuda and Kenso Soai

Chemical Communications 2009 (Issue 37) pp:5621-5623

Publication Date(Web):21 Aug 2009

DOI:10.1039/B912813A

Chiral isotactic polystyrenes induce the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, affording the enantiomerically enriched pyrimidyl alkanol with the corresponding absolute configuration to that of cryptochiral polystyrenes in conjunction with asymmetric autocatalysis.

Highly enantioselective asymmetric autocatalysis using chiral ruthenium complex-ion-exchanged synthetic hectorite as a chiral initiator

Co-reporter:Tsuneomi Kawasaki, Toshiki Omine, Kenta Suzuki, Hisako Sato, Akihiko Yamagishi and Kenso Soai

Organic & Biomolecular Chemistry 2009 vol. 7(Issue 6) pp:1073-1075

Publication Date(Web):23 Jan 2009

DOI:10.1039/B823282B

The synthetic hectorite containing intercalated chiral Δ- and Λ-tris(1,10-phenanthroline)ruthenium(II) ions acts as a heterogeneous chiral catalyst in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde to afford, in combination with asymmetric autocatalytic amplification of enantiomeric excess, 5-pyrimidyl alkanol with high enantiomeric excess.

Asymmetric Autocatalysis Triggered by Carbon Isotope (13C/12C) Chirality

Co-reporter:Kenta Suzuki;Takashi Tsutsumi;Yukari Matsumura;Tsuneomi Kawasaki;Masateru Ito

Science 2009 Volume 324(Issue 5926) pp:492-495

Publication Date(Web):24 Apr 2009

DOI:10.1126/science.1170322

The origin of chirality in asymmetric autocatalysis is due to carbon isotope substitution.

Achiral Nucleobase Cytosine Acts as an Origin of Homochirality of Biomolecules in Conjunction with Asymmetric Autocatalysis

Co-reporter:Tsuneomi Kawasaki Dr.;Kenta Suzuki;Yuko Hakoda Dr.

Angewandte Chemie International Edition 2008 Volume 47( Issue 3) pp:496-499

Publication Date(Web):

DOI:10.1002/anie.200703634

Achiral Nucleobase Cytosine Acts as an Origin of Homochirality of Biomolecules in Conjunction with Asymmetric Autocatalysis

Co-reporter:Tsuneomi Kawasaki Dr.;Kenta Suzuki;Yuko Hakoda Dr.

Angewandte Chemie 2008 Volume 120( Issue 3) pp:506-509

Publication Date(Web):

DOI:10.1002/ange.200703634

Enantioselective synthesis mediated by chiral crystal of achiral hippuric acid in conjunction with asymmetric autocatalysis

Co-reporter:Tsuneomi Kawasaki, Kenta Suzuki, Kunihiko Hatase, Masanari Otsuka, Hideko Koshima and Kenso Soai

Chemical Communications 2006 (Issue 17) pp:1869-1871

Publication Date(Web):21 Mar 2006

DOI:10.1039/B602442D

Enantiomorphous crystals composed of achiral hippuric acid, i.e., naturally occurring N-benzoylglycine, have been used successfully as chiral inducers in enantioselective synthesis in combination with asymmetric autocatalysis to afford the product with extremely high enantiomeric excess.

Enantioselective synthesis induced by tetrathia-[7]-helicenes in conjunction with asymmetric autocatalysis

Co-reporter:Tsuneomi Kawasaki, Kenta Suzuki, Emanuela Licandro, Alberto Bossi, Stefano Maiorana, Kenso Soai

Tetrahedron: Asymmetry 2006 Volume 17(Issue 14) pp:2050-2053

Publication Date(Web):28 August 2006

DOI:10.1016/j.tetasy.2006.07.015

Highly enantioenriched 5-pyrimidyl alkanol was formed using tetrathia-[7]-helicenes as a chiral initiator in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, in conjunction with asymmetric autocatalysis.(P)-(+)-7,8-Dipropyldithieno[3,2-e:3′,2′-e′]benzo[1,2-b:4,3-b′]bis[1]benzothiopheneC28H22S4Ee = 98.9%[α]D20=+685 (c 0.187, CHCl3)Source of chirality: resolution using HPLC with a chiral stationary phase (Chiralpak IA)Absolute configuration: P

Asymmetric autocatalysis of a ferrocene-containing chiral compound with amplification of chirality

Co-reporter:François Lutz, Tsuneomi Kawasaki, Kenso Soai

Tetrahedron: Asymmetry 2006 Volume 17(Issue 4) pp:486-490

Publication Date(Web):20 February 2006

DOI:10.1016/j.tetasy.2006.01.022

Chiral ferrocene-containing pyrimidyl alkanol can be efficiently synthesized via asymmetric autocatalysis as an enantiomerically pure product. Moreover, a remarkable positive nonlinear effect occurs during this autocatalytic reaction. Starting from a nearly racemic seed, it is thus possible to produce a larger amount of the same compound with high ee.(S)-1-(2-Ferrocenylethynyl-5-pyrimidyl)-2-methylpropan-1-olC20H20FeN2OEe >99%[α]D18=-18.0 (c 0.99, CHCl3)Source of chirality: asymmetric autocatalysisAbsolute configuration: S

Discovery of asymmetric autocatalysis with amplification of chirality and its implication in chiral homogeneity of biomolecules

Co-reporter:Kenso Soai;Tsuneomi Kawasaki

Chirality 2006 Volume 18(Issue 7) pp:469-478

Publication Date(Web):4 MAY 2006

DOI:10.1002/chir.20289

Spontaneous absolute asymmetric synthesis in the presence of achiral silica gel in conjunction with asymmetric autocatalysis

Co-reporter:Tsuneomi Kawasaki;Kenta Suzuki;Masako Shimizu;Keisuke Ishikawa

Chirality 2006 Volume 18(Issue 7) pp:479-482

Publication Date(Web):12 APR 2006

DOI:10.1002/chir.20273

An enantiomerically enriched pyrimidyl alkanol with either S or R configurations was obtained stochastically from the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc in the presence of achiral silica gel in conjunction with asymmetric autocatalysis with amplification of chirality. Chirality 18:479–482, 2006. © 2006 Wiley-Liss, Inc.

Asymmetric Amplification Using Chiral Cocrystals Formed from Achiral Organic Molecules by Asymmetric Autocatalysis

Co-reporter:Tsuneomi Kawasaki Dr.;Kazumichi Jo;Hirotaka Igarashi;Itaru Sato Dr.;Masaki Nagano;Hideko Koshima Dr. Dr.

Angewandte Chemie International Edition 2005 Volume 44(Issue 18) pp:

Publication Date(Web):30 MAR 2005

DOI:10.1002/anie.200462963

Enantioselective addition of diisopropylzinc to a pyrimidine-5-carbaldehyde was induced by chiral cocrystals of achiral two-component molecular crystals of tryptamine/para-chlorobenzoic acid (see scheme) and 3-indolepropionic acid/phenanthridine. This reaction, in conjunction with asymmetric autocatalysis, afforded a pyrimidyl alkanol in high enantiomeric excess.

Asymmetric Amplification Using Chiral Cocrystals Formed from Achiral Organic Molecules by Asymmetric Autocatalysis

Co-reporter:Tsuneomi Kawasaki Dr.;Kazumichi Jo;Hirotaka Igarashi;Itaru Sato Dr.;Masaki Nagano;Hideko Koshima Dr. Dr.

Angewandte Chemie 2005 Volume 117(Issue 18) pp:

Publication Date(Web):30 MAR 2005

DOI:10.1002/ange.200462963

Enantioselektiv addiert Diisopropylzink an einen Pyrimidin-5-carbaldehyd in Gegenwart chiraler Cokristalle aus achiralen Zweikomponenten-Molekülkristallen von Tryptamin/para-Chlorbenzoesäure (siehe Schema) und 3-Indolpropionsäure/Phenanthridin. Diese Reaktion lieferte in Kombination mit asymmetrischer Autokatalyse ein Pyrimidylalkanol in hohem Enantiomerenüberschuss.

Asymmetric Synthesis Utilizing Circularly Polarized Light Mediated by the Photoequilibrium of Chiral Olefins in Conjunction with Asymmetric Autocatalysis

Co-reporter:Itaru Sato Dr.;Rie Sugie;Yohei Matsueda;Yuri Furumura Dr.

Angewandte Chemie 2004 Volume 116(Issue 34) pp:

Publication Date(Web):25 AUG 2004

DOI:10.1002/ange.200454162

Es werde Licht! Ein asymmetrisches Photogleichgewicht und eine Autokatalyse sind die Quellen der Homochiralität in einer hoch enantioselektiven Synthese von chiralen Alkoholen (siehe Schema). Der Prozess wird durch links- oder rechtszirkular polarisiertes Licht (CPL) ausgelöst. Dabei wird ein Photogleichgewicht zwischen chiralen Olefinsubstraten genutzt, um die entsprechenden (2-Alkinyl-5-pyrimidyl)-substituierten Alkanole zu erhalten.

Asymmetric Synthesis Utilizing Circularly Polarized Light Mediated by the Photoequilibrium of Chiral Olefins in Conjunction with Asymmetric Autocatalysis

Co-reporter:Itaru Sato Dr.;Rie Sugie;Yohei Matsueda;Yuri Furumura Dr.

Angewandte Chemie International Edition 2004 Volume 43(Issue 34) pp:

Publication Date(Web):25 AUG 2004

DOI:10.1002/anie.200454162

The light touch: Asymmetric photoequilibrium and autocatalysis act as sources of homochirality in a highly enantioselective preparation of chiral alcohols (see scheme). This process is initiated by left- and right-circularly polarized light (CPL) and exploits the resulting photoequilibrium between chiral olefin substrates to yield 2-alkynyl-5-pyrimidyl alkanols.

Asymmetric autocatalysis induced by chiral hydrocarbon [2.2]paracyclophanes

Co-reporter:Itaru Sato, Atsushi Ohno, Yohei Aoyama, Toshinari Kasahara and Kenso Soai

Organic & Biomolecular Chemistry 2003 vol. 1(Issue 2) pp:244-246

Publication Date(Web):12 Dec 2002

DOI:10.1039/B209520N

Chiral hydrocarbon [2.2]paracyclophanes act as chiral initiators in asymmetric autocatalysis in the addition of diisopropylzinc to pyrimidine-5-carbaldehyde and give highly enantiomerically enriched 5-pyrimidyl alkanol with a reversed sense of the enantioselectivity to that of other [2.2]paracyclophanes with heteroatoms.

Relationship between the time, yield, and enantiomeric excess of asymmetric autocatalysis of chiral 2-alkynyl-5-pyrimidyl alkanol with amplification of enantiomeric excess

Co-reporter:Itaru Sato, Daisuke Omiya, Hiroyoshi Igarashi, Keiichi Kato, Yoshihiro Ogi, Koichi Tsukiyama, Kenso Soai

Tetrahedron: Asymmetry 2003 Volume 14(Issue 8) pp:975-979

Publication Date(Web):18 April 2003

DOI:10.1016/S0957-4166(03)00164-2

Experimental and kinetic analysis of asymmetric autocatalysis with amplification of ee in the enantioselective addition of diisopropylzinc to 2-alkynylpyrimidine-5-carbaldehyde using chiral 2-alkynyl-5-pyrimidyl alkanol with low ee's are described.Graphic

Amplification of Chirality from Extremely Low to Greater than 99.5 % ee by Asymmetric Autocatalysis

Co-reporter:Itaru Sato Dr.;Hiroki Urabe;Saori Ishiguro;Takanori Shibata Dr. Dr.

Angewandte Chemie International Edition 2003 Volume 42(Issue 3) pp:

Publication Date(Web):20 JAN 2003

DOI:10.1002/anie.200390105

“Single-handedly”, in every sense of the word, the alkylation product shown catalyzes its own asymmetric formation from the corresponding aldehyde. In this way the miniscule initial enantiomeric excess of about 0.00005 % was amplified to >99.5 % ee after three cycles.

Amplification of Chirality from Extremely Low to Greater than 99.5 % ee by Asymmetric Autocatalysis

Co-reporter:Itaru Sato Dr.;Hiroki Urabe;Saori Ishiguro;Takanori Shibata Dr. Dr.

Angewandte Chemie 2003 Volume 115(Issue 3) pp:

Publication Date(Web):20 JAN 2003

DOI:10.1002/ange.200390073

Autokatalyse mit starker Auswirkung: Das hier gezeigte Isopropylierungsprodukt katalysiert seine eigene asymmetrische Bildung aus dem entsprechenden Aldehyd. Auf diese Weise wird der anfangs winzige Enantiomerenüberschuss von nur 0.00005 % ee nach drei Zyklen auf >99.5 % ee verstärkt.

Highly Enantioselective Asymmetric Autocatalysis of Pyrimidin-5-yl Alkanol Induced by Chiral 1,3-Disubstituted Hydrocarbon Allenes

Co-reporter:Itaru Sato;Yohei Matsueda;Kousuke Kadowaki;Shigeru Yonekubo;Takanori Shibata

Helvetica Chimica Acta 2002 Volume 85(Issue 10) pp:3383-3387

Publication Date(Web):7 NOV 2002

DOI:10.1002/1522-2675(200210)85:10<3383::AID-HLCA3383>3.0.CO;2-B

1,3-Disubstituted chiral allenes without any heteroatoms act as chiral initiators in the addition of (i-Pr)₂Zn to pyrimidine-5-carbaldehyde to afford, in combination with the subsequent asymmetric autocatalysis, chiral pyrimidin-5-yl alkanols with up to 98% ee. The absolute configuration of the pyrimidin-5-yl alkanol formed depend on that of the chiral allene.

Highly enantioselective asymmetric autocatalysis using chiral ruthenium complex-ion-exchanged synthetic hectorite as a chiral initiator

Co-reporter:Tsuneomi Kawasaki, Toshiki Omine, Kenta Suzuki, Hisako Sato, Akihiko Yamagishi and Kenso Soai

Organic & Biomolecular Chemistry 2009 - vol. 7(Issue 6) pp:NaN1075-1075

Publication Date(Web):2009/01/23

DOI:10.1039/B823282B

The synthetic hectorite containing intercalated chiral Δ- and Λ-tris(1,10-phenanthroline)ruthenium(II) ions acts as a heterogeneous chiral catalyst in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde to afford, in combination with asymmetric autocatalytic amplification of enantiomeric excess, 5-pyrimidyl alkanol with high enantiomeric excess.

Asymmetric autocatalysis initiated by achiral nucleic acid base adenine: implications on the origin of homochirality of biomolecules

Co-reporter:Hiroko Mineki, Taichi Hanasaki, Arimasa Matsumoto, Tsuneomi Kawasaki and Kenso Soai

Chemical Communications 2012 - vol. 48(Issue 85) pp:NaN10540-10540

Publication Date(Web):2012/08/31

DOI:10.1039/C2CC34928K

Enantiomorphous crystals of adeninium dinitrate acted as the source of chirality in asymmetric autocatalysis producing highly enantioenriched (S)- and (R)-5-pyrimidyl alkanols, with the absolute configurations corresponding to that of crystals.

Reversal of the sense of enantioselectivity between 1- and 2-aza[6]helicenes used as chiral inducers of asymmetric autocatalysis

Co-reporter:Arimasa Matsumoto, Kento Yonemitsu, Hanae Ozaki, Jiří Míšek, Ivo Starý, Irena G. Stará and Kenso Soai

Organic & Biomolecular Chemistry 2017 - vol. 15(Issue 6) pp:NaN1324-1324

Publication Date(Web):2017/01/09

DOI:10.1039/C6OB02745H

Reversal of the sense of enantioselectivity was observed between 1-aza[6]helicene 2 and 2-aza[6]helicene 3 employed as chiral inducers of asymmetric autocatalysis of pyrimidyl alkanol. In the presence of (P)-(+)-1-aza[6]helicene 2, the reaction of pyrimidine-5-carbaldehyde 1 with diisopropylzinc afforded, in conjunction with asymmetric autocatalysis, (S)-pyrimidyl alkanol 4 with high ee. Surprisingly, the reaction in the presence of (P)-(+)-2-aza[6]helicene 3 gave the opposite enantiomer of (R)-alkanol 4 with high ee. In the same manner, (M)-(−)-2 and (M)-(−)-3 afforded (R)- and (S)-alkanol 4, respectively. The sense of enantioselectivity is controlled not only by the helicity of the azahelicene derivatives but also by the position of the nitrogen atom.

Unusual reversal of enantioselectivity in the asymmetric autocatalysis of pyrimidyl alkanol triggered by chiral aromatic alkanols and amines

Co-reporter:Arimasa Matusmoto, Satoshi Fujiwara, Yui Hiyoshi, Kerstin Zawatzky, Alexey A. Makarov, Christopher J. Welch and Kenso Soai

Organic & Biomolecular Chemistry 2017 - vol. 15(Issue 3) pp:NaN558-558

Publication Date(Web):2016/12/02

DOI:10.1039/C6OB02415G

Temperature dependent inversion of enantioselectivity in asymmetric catalysis is an interesting and somewhat unusual phenomenon. We have observed temperature dependent inversion of enantioselectivity in the asymmetric autocatalysis reaction when triggered by a wide scope of enantioenriched alcohols and amines. The addition reaction of diisopropylzinc to pyrimidine-5-carbaldehyde in the presence of enantiopure alcohols or amines affords the pyrimidyl alkanol product at 0 °C with high ee. However, lowering the reaction temperature to −44 °C affords the opposite enantioselectivity.

Can the analyte-triggered asymmetric autocatalytic Soai reaction serve as a universal analytical tool for measuring enantiopurity and assigning absolute configuration?

Co-reporter:Christopher J. Welch, Kerstin Zawatzky, Alexey A. Makarov, Satoshi Fujiwara, Arimasa Matsumoto and Kenso Soai

Organic & Biomolecular Chemistry 2017 - vol. 15(Issue 1) pp:NaN101-101

Publication Date(Web):2016/09/28

DOI:10.1039/C6OB01939K

An investigation is reported on the use of the autocatalytic enantioselective Soai reaction, known to be influenced by the presence of a wide variety of chiral materials, as a generic tool for measuring the enantiopurity and absolute configuration of any substance. Good generality for the reaction across a small group of test analytes was observed, consistent with literature reports suggesting a diversity of compound types that can influence the stereochemical outcome of this reaction. Some trends in the absolute sense of stereochemical enrichment were noted, suggesting the possible utility of the approach for assigning absolute configuration to unknown compounds, by analogy to closely related species with known outcomes. Considerable variation was observed in the triggering strength of different enantiopure materials, an undesirable characteristic when dealing with mixtures containing minor impurities with strong triggering strength in the presence of major components with weak triggering strength. A strong tendency of the reaction toward an ‘all or none’ type of behavior makes the reaction most sensitive for detecting enantioenrichment close to zero. Consequently, the ability to discern modest from excellent enantioselectivity was relatively poor. While these properties limit the ability to obtain precise enantiopurity measurements in a simple single addition experiment, prospects may exist for more complex experimental setups that may potentially offer improved performance.

Helical mesoporous silica as an inorganic heterogeneous chiral trigger for asymmetric autocatalysis with amplification of enantiomeric excess

Co-reporter:Tsuneomi Kawasaki, Yuko Araki, Kunihiko Hatase, Kenta Suzuki, Arimasa Matsumoto, Toshiyuki Yokoi, Yoshihiro Kubota, Takashi Tatsumi and Kenso Soai

Chemical Communications 2015 - vol. 51(Issue 42) pp:NaN8744-8744

Publication Date(Web):2015/03/16

DOI:10.1039/C5CC01750E

Mesoporous silica has been used as a heterogeneous support for catalysts; however, asymmetric induction by the helicity of inorganic mesoporous silica itself has not yet been achieved. P- and M-helical mesoporous silica was found to act as a chiral inorganic trigger for asymmetric autocatalysis to afford (S) and (R)-pyrimidyl alkanol with >99.5% ee, respectively.

A reversal phenomenon of enantioface selectivity by the cooperative operation of two chiral catalysts

Co-reporter:Tsuneomi Kawasaki, Yuki Wakushima, Mai Asahina, Kazuya Shiozawa, Tomoyuki Kinoshita, François Lutz and Kenso Soai

Chemical Communications 2011 - vol. 47(Issue 18) pp:NaN5279-5279

Publication Date(Web):2011/03/22

DOI:10.1039/C1CC10136F

The reversal phenomenon of enantioface selectivity in the asymmetric addition of diisopropylzinc to aldehydes was observed by mixing two chiral β-amino alcohol catalysts. The opposite enantiomeric product was formed on using a mixture of two chiral catalysts that possess individual enantioselectivity.

Discrimination of cryptochirality in chiral isotactic polystyrene by asymmetric autocatalysis

Co-reporter:Tsuneomi Kawasaki, Christiane Hohberger, Yuko Araki, Kunihiko Hatase, Klaus Beckerle, Jun Okuda and Kenso Soai

Chemical Communications 2009(Issue 37) pp:NaN5623-5623

Publication Date(Web):2009/08/21

DOI:10.1039/B912813A

Chiral isotactic polystyrenes induce the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, affording the enantiomerically enriched pyrimidyl alkanol with the corresponding absolute configuration to that of cryptochiral polystyrenes in conjunction with asymmetric autocatalysis.

Asymmetric autocatalysis induced by meteoritic amino acids with hydrogen isotope chirality

Co-reporter:Tsuneomi Kawasaki, Masako Shimizu, Daisuke Nishiyama, Masateru Ito, Hitomi Ozawa and Kenso Soai

Chemical Communications 2009(Issue 29) pp:NaN4398-4398

Publication Date(Web):2009/06/24

DOI:10.1039/B908754K

Achiral meteoritic amino acids, glycine and α-methylalanine, with hydrogen isotope (D/H) chirality, acted as the source of chirality in asymmetric autocatalysis with amplification of ee to afford highly enantioenriched 5-pyrimidyl alkanols.

Asymmetric autocatalysis triggered by oxygen isotopically chiral glycerin

Co-reporter:Arimasa Matsumoto, Shotaro Oji, Shizuka Takano, Kyohei Tada, Tsuneomi Kawasaki and Kenso Soai

Organic & Biomolecular Chemistry 2013 - vol. 11(Issue 18) pp:NaN2931-2931

Publication Date(Web):2013/03/05

DOI:10.1039/C3OB40293B

Chiral (S)- and (R)-18O-glycerin induces enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, and the subsequent asymmetric autocatalysis affords (R)- and (S)-pyrimidyl alkanol with high enantiomeric excess, respectively.

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