Takuji Hirose

Name:

Organization: Saitama University , Japan

Department: Graduate School of Science and Engineering

Title: Professor(PhD)

Chemicals
References

An efficient metal- and solvent-free organocatalytic system for chemical fixation of CO2 into cyclic carbonates under mild conditions

Co-reporter:Lin Wang, Guangyou Zhang, Koichi Kodama and Takuji Hirose

Green Chemistry 2016 vol. 18(Issue 5) pp:1229-1233

Publication Date(Web):10 Dec 2015

DOI:10.1039/C5GC02697K

An efficient, metal- and solvent-free catalytic system was developed for the conversion of CO2 and epoxides to the corresponding cyclic carbonates under mild conditions (T = 25–45 °C, 1 atm CO2) in high-to-excellent yields. The catalyst could be easily recycled, providing a more sustainable process for the chemical fixation of CO2.

DBU/benzyl bromide: an efficient catalytic system for the chemical fixation of CO2 into cyclic carbonates under metal- and solvent-free conditions

Co-reporter:Lin Wang, Koichi Kodama and Takuji Hirose

Catalysis Science & Technology 2016 vol. 6(Issue 11) pp:3872-3877

Publication Date(Web):22 Dec 2015

DOI:10.1039/C5CY01892G

A simple, mild, and inexpensive catalytic system consisting of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and benzyl bromide was developed for the cycloaddition of epoxides with ambient CO2 under metal-free and solvent-free conditions. Moreover, a wide range of epoxides was converted to the corresponding cyclic carbonates with good to excellent yields (81–95%).

Economical synthesis of cyclic carbonates from carbon dioxide and halohydrins using K2CO3

Co-reporter:Takuji Hirose, Shinsuke Shimizu, Shujie Qu, Hiroaki Shitara, Koichi Kodama and Lin Wang

RSC Advances 2016 vol. 6(Issue 73) pp:69040-69044

Publication Date(Web):15 Jul 2016

DOI:10.1039/C6RA13008A

A highly simple, economical, and selective synthesis of five-membered cyclic carbonates was achieved by the reaction of CO2 with 1,2-halohydrins in the presence of K2CO3. This method allows the efficient preparation of cyclic carbonates (72–95% yields for monosubstituted cyclic carbonates and 43% for 1,1- and 1,2-disubstituted cyclic carbonates) under mild reaction conditions, atmospheric pressure of CO2 at 30 °C, and not only in dry DMF, but also in commercial “anhydrous” DMF. The reaction mechanism was elucidated using the SEM and XRD data of the by-products, KHCO3 and KBr.

Direct enantioseparation of diarylmethylamines with an ortho-hydroxy group via diastereomeric salt formation and their application to the enantioselective addition reaction of diethylzinc

Co-reporter:Koichi Kodama, Naoki Hayashi, Yasuhiko Yoshida, Takuji Hirose

Tetrahedron 2016 Volume 72(Issue 10) pp:1387-1394

Publication Date(Web):10 March 2016

DOI:10.1016/j.tet.2016.01.034

Two chiral diarylmethylamines with a phenolic hydroxy group at their ortho positions (1c and 1d) were synthesized, and their direct enantioseparation via diastereomeric salt formation was investigated. Crystallographic analyses of the diastereomeric salts involving 1c were conducted: water molecules incorporated in the space played an important role in chiral recognition. Enantiopure 1 were applied for the enantioselective addition of diethylzinc to benzaldehyde. Ligand (R)-1d afforded the product in very high yield (96%) and enantiopurity (92% ee). Not only the phenyl group on the stereogenic center of (R)-1d but also its bulky tert-butyl group is important for chiral induction.

Cationic polymerization of vinyl ethers and p-methoxystyrene by a benign initiating system: Silver salt/arylmethyl halide/dialkyl sulfide

Co-reporter:Li Lin;Guangyou Zhang;Koichi Kodama;Hiroaki Shitara

Journal of Polymer Science Part A: Polymer Chemistry 2016 Volume 54( Issue 6) pp:861-870

Publication Date(Web):

DOI:10.1002/pola.27925

ABSTRACT

Three vinyl ethers (VEs: isobutyl vinyl ether, ethyl vinyl ether, and isopropyl vinyl ether) and an active styrene derivative, p-methoxystyrene (pMOS), were employed for cationic polymerization using a benign initiating system, AgClO₄/Ph₂CHBr/dialkyl sulfide. Choosing a sulfide with suitable nucleophilicity was important for achieving controlled polymerization. Additionally, selecting an appropriate reaction temperature based on monomer reactivity was also crucial for suppressing side reactions. Highly controlled polymerizations of VEs and pMOS were further confirmed by proton nuclear magnetic resonance (¹H NMR) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In addition, the coordination of the arylmethyl cation to the added base obviously influenced the initiation, as demonstrated by ¹H NMR analysis. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 861–870

A benign initiating system for cationic polymerization of isobutyl vinyl ether: Silver salt/aryl(alkyl) halide/lewis base

Co-reporter:Li Lin;Guangyou Zhang;Koichi Kodama;Mikio Yasutake

Journal of Polymer Science Part A: Polymer Chemistry 2015 Volume 53( Issue 17) pp:2050-2058

Publication Date(Web):

DOI:10.1002/pola.27656

ABSTRACT

Aryl(alkyl) halides and silver salts were studied as environmentally benign initiating systems for cationic polymerization of isobutyl vinyl ether (IBVE). The reactivity of the benzyl cations could be effectively controlled by using dimethyl sulfide (Me₂S) as an additive, which was shown to be an effective Lewis base (LB), and diethyl ether as a reaction solvent. Detailed study of various benzyl cations and the order of addition of the reagents revealed that the reaction was controlled by the electronic and steric features of aryl(alkyl) halides, LBs, and IBVE, and a plausible reaction mechanism was presented. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2050–2058

Synthesis of cyclic carbonates from CO2 and epoxides catalyzed by low loadings of benzyl bromide/DMF at ambient pressure

Co-reporter:Lin Wang, Li Lin, Guangyou Zhang, Koichi Kodama, Mikio Yasutake and Takuji Hirose

Chemical Communications 2014 vol. 50(Issue 94) pp:14813-14816

Publication Date(Web):09 Oct 2014

DOI:10.1039/C4CC06791F

An efficient, metal-free catalytic system for the conversion of CO2 and epoxides to cyclic carbonates under mild conditions with good-to-excellent yields (57–99%) was developed. A possible reaction mechanism involving the electrophilic activation of epoxides by benzyl cations and nucleophilic activation of CO2 by DMF is proposed.

Synthesis and spectral properties of ruthenium(II) complexes based on 2,2′-bipyridines modified by a perylene chromophore

Co-reporter:Koichi Kodama, Akinori Kobayashi, Takuji Hirose

Tetrahedron Letters 2013 Volume 54(Issue 40) pp:5514-5517

Publication Date(Web):2 October 2013

DOI:10.1016/j.tetlet.2013.07.150

Five new 2,2′-bipyridines functionalized with a perylene or a perylenediimide moiety were synthesized and the corresponding heteroleptic ruthenium(II) complexes ([Ru(bpy)2(L)](PF6)2; bpy = 2,2′-bipyridyl, L = perylene-substituted bpy ligand) were prepared. The UV–vis spectra of the ruthenium(II) complexes showed red-shifted and intense absorption bands derived from the conjugated structure of the new ligands.

Solvent-Induced Reversed Stereoselectivity in Reciprocal Resolutions of Mandelic Acid and erythro-2-Amino-1,2-diphenylethanol

Co-reporter:Hiroaki Shitara, Toshiki Shintani, Koichi Kodama, and Takuji Hirose

The Journal of Organic Chemistry 2013 Volume 78(Issue 18) pp:9309-9316

Publication Date(Web):August 7, 2013

DOI:10.1021/jo401517q

Solvent-induced chirality switching in reciprocal optical resolution between mandelic acid (1) and erythro-2-amino-1,2-diphenylethanol (2) has been demonstrated. The stereochemistry of the deposited salts was controlled by changing the crystallization solvent from 1-PrOH or 1-BuOH to 1,4-dioxane. It was revealed from 1H NMR spectra, thermogravimetric analysis, and X-ray crystallography of the salts that an equimolar amount of the crystallization solvent was incorporated in each diastereomeric salt. On the basis of the crystal structures, it was found that both the hydrogen-bonding ability and the size of the solvent molecule played an important role. Differences in the formed hydrogen-bonding networks (columnar or sheetlike structure) and their packing manner were found to be crucial for the reversed stereoselectivity. Furthermore, pseudopolymorphic salt crystals that incorporated 1,4-dioxane were obtained during the enantioseparation of racemic 2, and their solid-state properties were examined by measurement of their IR spectra. This solvent-induced dual stereocontrol technique was successfully applied to the successive resolution process, eliminating the need to change the resolving agent for access to both enantiomers of 1 and 2.

Cyanative self-condensation of aromatic aldehydes promoted by VO(OiPr)3–Lewis base as a cooperative catalyst

Co-reporter:Koichi Kodama, Hiroaki Kawamata, Naoya Takahashi and Takuji Hirose

Organic & Biomolecular Chemistry 2012 vol. 10(Issue 47) pp:9440-9446

Publication Date(Web):17 Oct 2012

DOI:10.1039/C2OB26811F

Self-condensation of aromatic aldehydes with trimethylsilyl cyanide proceeded by the cooperative catalytic effect of VO(OiPr)3 and a Lewis base to give the corresponding O-acylated cyanohydrins. The reaction conversion and selectivity were strongly dependent on the solvent used, the Lewis base, and the presence of oxygen. All the nine kinds of aromatic aldehydes considered herein afforded the O-acylated cyanohydrins with excellent selectivity under an O2 atmosphere.

Switching of Enantioselectivity in the Catalytic Addition of Diethylzinc to Aldehydes by Regioisomeric Chiral 1,3-Amino Sulfonamide Ligands

Co-reporter:Takuji Hirose, Kazuyuki Sugawara, and Koichi Kodama

The Journal of Organic Chemistry 2011 Volume 76(Issue 13) pp:5413-5428

Publication Date(Web):May 19, 2011

DOI:10.1021/jo200834n

Twenty chiral 1,3-amino sulfonamides of two classes (2a–i and 3a–k) have been prepared from (−)-cis-2-benzamidocyclohexanecarboxylic acid (1) and studied as ligands for catalytic enantioselective addition of Et2Zn to a variety of aromatic and aliphatic aldehydes. The ligands 2 and 3 are regioisomers in which the position of the amine and sulfonamide groups is exchanged. Each class of ligands with the same chirality was shown to afford sec-alcohols with the opposite stereochemistry. Structural surveys revealed that the combination of tertiary amino and p-toluenesufonylamido groups works most effectively for the reaction. Through optimization of the structural and reaction conditions, the best ligands quantitatively provided both enantiomeric secondary alcohols in good to excellent enantioselectivity of up to 94% and 98% ee for (S)- and (R)-enantiomers, respectively.

Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine via diastereomeric salt formation

Co-reporter:Koichi Kodama;Yuria Kimura;Hiroaki Shitara;Mikio Yasutake;Rumiko Sakurai

Chirality 2011 Volume 23( Issue 4) pp:326-332

Publication Date(Web):

DOI:10.1002/chir.20922

Abstract

Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine 1 by N-(p-toluenesulfonyl)-(S)-phenylalanine 2 via diastereomeric salt formation was studied. (S)-1·(S)-2 was preferentially crystallized as a less-soluble salt from aqueous alcohol, while (R)-1·(S)-2 salt was mainly obtained by addition of solvents with a six-membered ring such as dioxane, cyclohexane, tetrahydropyran, and cyclohexene to 2-propanol. Further investigations were carried out from the viewpoints of molecular structures, optical rotation measurement, and X-ray crystallographic analyses. Crystallographic analyses have revealed that incorporation of the six-membered ring solvent molecule in (R)-1·(S)-2 without hydrogen bonds changed the molecular conformation of (S)-2 to stabilize the salt, which changed the selectivity of 1 in the enantioseparation. Chirality, 2011. © 2010 Wiley-Liss, Inc.

Synthesis of Chiral 1,3-Diamines Derived from cis-2-Benzamidocyclohexanecarboxylic Acid and Their Application in the Cu-Catalyzed Enantioselective Henry Reaction

Co-reporter:Dr. Koichi Kodama;Kazuyuki Sugawara ; Takuji Hirose

Chemistry - A European Journal 2011 Volume 17( Issue 48) pp:13584-13592

Publication Date(Web):

DOI:10.1002/chem.201102136

Abstract

In this study, 13 different chiral 1,3-diamines were synthesized from (−)-cis-2-benzamidocyclohexanecarboxylic acid. They were successfully applied as ligands in the Cu-catalyzed asymmetric Henry reaction between benzaldehyde and nitromethane. It was confirmed that the enantioselectivity of the product could be controlled by the substituents on the two amino groups. A time-course study revealed a decrease in product enantioselectivity caused by spontaneous retro-Henry reaction, which was suppressed by conducting the reaction at 0 °C. This versatile reaction afforded various β-nitroalcohols in excellent yields and enantioselectivities (up to 98 % yield, 91 % enantiomeric excess) under the optimized reaction conditions. The chiral induction mechanism was explained on the basis of a previously proposed transition-state model.

Chirality Control by Substituents in the Asymmetric Addition of Et2Zn to Aromatic Aldehydes Catalyzed by cis-(1R,2S)-2-Benzamidocyclohexanecarboxylic Acid Derived 1,3-Aminoalcohols

Co-reporter:Xiangbo Wang;Koichi Kodama;Guangyou Zhang

Chinese Journal of Chemistry 2010 Volume 28( Issue 1) pp:61-68

Publication Date(Web):

DOI:10.1002/cjoc.201090036

Abstract

A series of novel optically active 1,3-aminoalcohols based on cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acid and trans-(1R,2R)-2-benzamidocyclohexanecarboxylic acid were synthesized and used in the asymmetric diethylzinc addition to aromatic aldehydes. Not only the enantioselectivity but also the stereochemistry of the product were controlled by the N-substituents and the substituents on the vicinity carbon to hydroxyl group of the cis-derivatives.

Synthesis of new CO2-soluble ruthenium(II) and cobalt(II) polypyridine complexes bearing fluorinated alkyl chains and their application to photoreduction of liq. CO2

Co-reporter:Takuji Hirose, Shuhei Shigaki, Makoto Hirose, Atsushi Fushimi

Journal of Fluorine Chemistry 2010 Volume 131(Issue 9) pp:915-921

Publication Date(Web):September 2010

DOI:10.1016/j.jfluchem.2010.06.005

Eight types of new CO2-soluble or CO2-philic ruthenium(II) and cobalt(II) polypyridine complexes, namely, [M(F84OPh)3](BArF)2, [M(F44OPh)3](BArF)2, [M(F62Ph)3](BArF)2, and [M(F62O)3](BArF)2 (M = Ru or Co, BArF: tetrakis[3,5-bis(trifluoromethyl)phenyl]borate), were prepared from bipyridine derivatives bearing highly fluorinated alkyl chains and applied to the photoreduction of liq. CO2 under a high pressure of 6.8 MPa at 35 °C. All these complexes have higher philicity toward liq. CO2 than the corresponding complexes with PF6− as the counteranion. Using the Ru(II)–Co(II) systems of [M(F44OPh)3](BArF)2 and [M(F62O)3](BArF)2, direct photoreduction of CO2 was achieved without the use of any organic solvent.New CO2-soluble Ru(II) and Co(II) complexes, [M(F62O)3](BArF)2, were shown to be useful for the photoreduction of liq. CO2 under high pressure without the use of any other organic solvent.

Chirality control in the enantioselective arylation of aromatic aldehydes catalyzed by cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acid derived 1,3-aminoalcohols

Co-reporter:Xiang-Bo Wang, Koichi Kodama, Takuji Hirose, Xiao-Feng Yang, Guang-You Zhang

Tetrahedron: Asymmetry 2010 Volume 21(Issue 1) pp:75-80

Publication Date(Web):29 January 2010

DOI:10.1016/j.tetasy.2010.01.003

A series of chiral 1,3-aminoalcohols derived from cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acid were synthesized and applied to the enantioselective arylation of aromatic aldehydes. The reactions exhibited good yields (up to 90%) and moderate to high enantioselectivities (up to 99%). Not only the enantioselectivity but also the stereochemistry of the product were controlled by the substituent effect of the chiral ligands.(1R,2S)-2-Piperidin-1′-ylcyclohexylmethanolC12H23NO[α]D26=+16.5 (c 0.4, CHCl3)Source of chirality: cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acidAbsolute configuration: (1R,2S)(1R,2S)-(2-Benzylaminocyclohexyl)bis(3,5-dimethoxyphenyl)methanolC30H37NO5[α]D26=+64.7 (c 4.0, CHCl3)Source of chirality: cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acidAbsolute configuration: (1R,2S)

Novel chiral ammonium ionic liquids as efficient organocatalysts for asymmetric Michael addition of aldehydes to nitroolefins

Co-reporter:Wan-Hui Wang, Xiang-Bo Wang, Koichi Kodama, Takuji Hirose, Guang-You Zhang

Tetrahedron 2010 66(27–28) pp: 4970-4976

Publication Date(Web):

DOI:10.1016/j.tet.2010.05.030

Self-assembled proline-amino thioureas as efficient organocatalysts for the asymmetric Michael addition of aldehydes to nitroolefins

Co-reporter:Wan-Hui Wang, Takeshi Abe, Xiang-Bo Wang, Koichi Kodama, Takuji Hirose, Guang-You Zhang

Tetrahedron: Asymmetry 2010 Volume 21(Issue 24) pp:2925-2933

Publication Date(Web):20 December 2010

DOI:10.1016/j.tetasy.2010.11.025

A small co-catalyst library of amino thioureas has been established from chiral 1,3-diamines. These bifunctional thioureas can form assemblies with proline to cooperatively catalyze the asymmetric Michael addition of aldehydes to nitroolefins. Both the reaction rate (up to 98% yield for 18 h) and the enantioselectivity (up to 94% ee) were significantly improved upon in less polar solvents.1-(3,5-Bis(trifluoromethyl)phenyl)-3-((1R,2R)-2-((dimethylamino)methyl)cyclohexyl)thioureaC18H23F6N3S[α]D25=+83.8 (c 0.50, CHCl3)Source of chirality: (1S,2R)-2-benzamidocyclohexanecarboxylic acidAbsolute configuration: (1R,2R)1-(3,5-Bis(trifluoromethyl)benzyl)-3-((1R,2R)-2-((dimethylamino)methyl)cyclohexyl)thioureaC19H25F6N3S[α]D25=+95.1 (c 0.21, CHCl3)Source of chirality: (1S,2R)-2-benzamidocyclohexanecarboxylic acidAbsolute configuration: (1R,2R)1-(3,5-Difluorobenzyl)-3-((1R,2R)-2-((dimethylamino)methyl)cyclohexyl)thioureaC17H25F2N3S[α]D25=+118.4 (c 0.42, CHCl3)Source of chirality: (1S,2R)-2-benzamidocyclohexanecarboxylic acidAbsolute configuration: (1R,2R)1-((1R,2R)-2-((Dimethylamino)methyl)cyclohexyl)-3-phenylthioureaC16H25N3S[α]D25=+68.0 (c 0.20, CHCl3)Source of chirality: (1S,2R)-2-benzamidocyclohexanecarboxylic acidAbsolute configuration: (1R,2R)1-(3,5-Bis(trifluoromethyl)phenyl)-3-((1S,2R)-2-((dimethylamino)methyl)cyclohexyl)thioureaC18H23F6N3S[α]D25=-12.6 (c 0.39, CHCl3)Source of chirality: (1S,2S)-2-benzamidocyclohexanecarboxylic acidAbsolute configuration: (1S,2R)1-(3,5-Bis(trifluoromethyl)phenyl)-3-((1R,2R,3R,4S)-3-((dimethylamino)methyl)bicyclo[2.2.1]heptan-2-yl)thioureaC19H23F6N3S[α]D25=+141.4 (c 0.51, CHCl3)Source of chirality: (1S,2S,3R,4R)-3-benzamidobicyclo[2.2.1]heptane-2-carboxylic acidAbsolute configuration: (1R,2R,3R,4S)1-(3,5-Bis(trifluoromethyl)phenyl)-3-((1R,2R,3R,4S)-3-((4-methylpiperazin-1-yl)methyl)bicyclo[2.2.1]heptan-2-yl)thioureaC22H28F6N4S[α]D25=+19.9 (c 0.41, CHCl3)Source of chirality: (1S,2S,3R,4R)-3-benzamidobicyclo[2.2.1]heptane-2-carboxylic acidAbsolute configuration: (1R,2R,3R,4S)1-(3,5-Bis(trifluoromethyl)phenyl)-3-((1R,2S)-2-(hydroxymethyl)cyclohexyl)thioureaC16H18F6N2OS[α]D25=+11.5 (c 0.44, CHCl3)Source of chirality: (1S,2R)-2-benzamidocyclohexanecarboxylic acidAbsolute configuration: (1R,2S)

Catalytic enantioselective arylation of aryl aldehydes by chiral aminophenol ligands

Co-reporter:Xiao-Feng Yang, Takuji Hirose, Guang-You Zhang

Tetrahedron: Asymmetry 2009 Volume 20(Issue 4) pp:415-419

Publication Date(Web):11 March 2009

DOI:10.1016/j.tetasy.2009.01.025

The catalytic enantioselective arylation of aryl aldehydes using boronic acids as the source of transferable aryl groups is described; the reaction is found to proceed in good yields and in good to high enantioselectivities (up to 99% ee) in the presence of a chiral aminophenol ligand.(R)-2-(1-Amino-2,2-dimethylpropyl)-6-bromo-4-tert-butylphenolC15H24BrNOEe >99%[α]D20=-14.1 (c 1.0, MeOH)Source of chirality: (R)-2-(1-amino-2,2-dimethylpropyl)-4-tert-butylphenolAbsolute configuration: (R)

Solvent control of optical resolution of 2-amino-1-phenylethanol using dehydroabietic acid

Co-reporter:Kayoko Taniguchi, Marie Aruga, Mikio Yasutake and Takuji Hirose

Organic & Biomolecular Chemistry 2008 vol. 6(Issue 3) pp:458-463

Publication Date(Web):18 Dec 2007

DOI:10.1039/B717071H

The optical resolution of 2-amino-1-phenylethanol (2-APE) by the solvent switch method was investigated using dehydroabietic acid (DAA), a natural chiral acid obtained as one of the main components of disproportionated rosin. The solvent dependency of optical rotation measurements of 2-APE, DAA and the diastereomeric salts suggested solvent control of optical resolution. Both (R)- and (S)-2-APE were resolved, as the first success for aminoalcohols, only by changing the resolving solvents: (S)-2-APE was obtained in high optical purity by a single crystallization operation with polar solvents (ε > 50), whereas the efficiency was lower for (R)-2-APE using less polar solvents (20 < ε < 40). The results were compared and discussed with reference to the crystal structures of the diastereomeric salts.

Synthesis and Phase Structures of Novel -Acceptor Discotic Liquid Crystalline Compounds Having a Pyrenedione Core

Co-reporter:Mikio Yasutake;Takashi Fujihara;Akira Nagasawa;Keiichi Moriya

European Journal of Organic Chemistry 2008 Volume 2008( Issue 24) pp:4120-4125

Publication Date(Web):

DOI:10.1002/ejoc.200800360

Abstract

Several π-acceptor discotic liquid crystalline compounds were synthesized by using a pyrenedione unit as a core. Terrace-like and band-like structures were revealed by polarized optical microscopy (POM) observations and XRD measurements. In conjunction with the results of the single-crystal structure analysis of analogous crystalline compounds, all of the liquid crystalline compounds were confirmed to form a discotic lamellar phase D_L2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Synthesis of novel chiral tridentate aminophenol ligands for enantioselective addition of diethylzinc to aldehydes

Co-reporter:Xiao-Feng Yang, Takuji Hirose, Guang-You Zhang

Tetrahedron: Asymmetry 2008 Volume 19(Issue 14) pp:1670-1675

Publication Date(Web):25 July 2008

DOI:10.1016/j.tetasy.2008.06.027

Resolution of α-methylbenzylamine via diastereomeric salt formation using the naturally based reagent N-tosyl-(S)-phenylalanine together with a solvent switch technique

Co-reporter:Takuji Hirose, Muksana Begum, Md. Sadequl Islam, Kayoko Taniguchi, Mikio Yasutake

Tetrahedron: Asymmetry 2008 Volume 19(Issue 14) pp:1641-1646

Publication Date(Web):25 July 2008

DOI:10.1016/j.tetasy.2008.06.035

The resolution of (RS)-α-methylbenzylamine 1 with the naturally based reagent N-tosyl-(S)-phenylalanine 2 via the diastereomeric salt formation method together with the solvent switch technique has been investigated. In various alcoholic solvents with a wide ε range, the less-soluble salt was (S)-1·(S)-2, while (R)-1·(S)-2 was obtained when dioxane was used as a resolving solvent system. The highest enantiomeric purities of (S)-1 and (R)-1 were obtained from 2-PrOH and dioxane/MeOH, respectively. The X-ray single-crystal analysis showed that both (S)-1·(S)-2 and (R)-1·(S)-2 crystals form a hydrogen-bonding network; however, (R)-1·(S)-2 contains dioxane molecules without incorporation in the hydrogen-bonding network. The drastic effect of dioxane on the present system is interpreted as space filling.(S)-Methylbenzylamine·(S)-tosylphenylalanine saltC24H28N2O4S: 440.54[α]D27=+50.5 (c 0.107, MeOH)Absolute configuration: (S,S)(R)-Methylbenzylamine·(S)-tosylphenylalanine saltC24H28N2O4S: 440.54[α]D23=+78.5 (c 0.107, MeOH)Absolute configuration: (R,S)(R)-Methylbenzylamine·(S)-tosylphenylalanine·dioxane saltC28H36N2O6S: 528.65[α]D23=+20.7 (c 1.0, MeOH)Absolute configuration: (R,S)

Synthesis of novel chiral 1,3-aminophenols and application for the enantioselective addition of diethylzinc to aldehydes

Co-reporter:Xiao-Feng Yang, Zhao-Hui Wang, Tomoaki Koshizawa, Mikio Yasutake, Guang-You Zhang, Takuji Hirose

Tetrahedron: Asymmetry 2007 Volume 18(Issue 10) pp:1257-1263

Publication Date(Web):11 June 2007

DOI:10.1016/j.tetasy.2007.05.027

Novel chiral 1,3-aminophenols were efficiently synthesized by applying a Friedel–Crafts reaction and optical resolution. The catalytic activity of the aminophenols was studied for the addition of diethylzinc to benzaldehyde. The results showed that (S)-5a with bulky tert-butyl groups on the stereogenic carbon atom and 4,6-positions of phenol favored higher enantioselectivity (94% ee). The same ligand was also used with other aldehydes, to give optically active alcohols in good chemical yields and ee values (up to 99%).2-((R)-1-Amino-2-phenylethyl)-4-methylphenolC15H17NOEe >99%[α]D20=-48.0 (c 0.5, MeOH)Source of chirality: optical resolutionAbsolute configuration: (R)(−)-2-(1-Aminoethyl)-4-methylphenolC9H13NOEe >99%[α]D20=-16.2 (c 0.5, 0.1 M HCl (aq))Source of chirality: optical resolution(S)-2-(1-Amino-2,2-dimethylpropyl)-4-tert-butylphenolC15H25NOEe >99%[α]D20=-6.8 (c 0.326, diethyl ether)Source of chirality: (S)-2-(1-amino-2,2-dimethylpropyl)phenolAbsolute configuration: (S)(S)-2-(1-Amino-2-methylpropyl)-4-tert-butylphenolC14H23NOEe >99%[α]D20=-13.9 (c 0.36, CHCl3)Source of chirality: (S)-2-(1-amino-2-methylpropyl)phenolAbsolute configuration: (S)(S)-2-(1-Amino-2,2-dimethylpropyl)-4,6-di-tert-butylphenolC19H33NOEe >99%[α]D20=+22.0 (c 0.5, CH3COOCH2CH3)Source of chirality: (S)-2-(1-amino-2,2-dimethylpropyl)phenolAbsolute configuration: (S)(S)-2-(1-Amino-2-methylpropyl)-4,6-di-tert-butylphenolC18H31NOEe >99%[α]D20=+5.8 (c 0.584, diethyl ether)Source of chirality: (S)-2-(1-amino-2-methylpropyl)phenolAbsolute configuration: (S)(R)-2-(1-Amino-2-phenylethyl)-6-tert-butyl-4-methylphenolC19H25NOEe >99%[α]D20=-26.1 (c 1.8, CHCl3)Source of chirality: 2-((R)-1-amino-2-phenylethyl)-4-methylphenolAbsolute configuration: (R)(−)-2-(1-Aminoethyl)-6-tert-butyl-4-methylphenolC13H21NOEe >99%[α]D20=-21.2 (c 0.6, CHCl3)Source of chirality: (−)-2-(1-aminoethyl)-4-methylphenol

Enantioselective addition of phenylacetylene to aldehydes catalyzed by 1,3-aminophenol ligand

Co-reporter:Xiao-Feng Yang, Takuji Hirose, Guang-You Zhang

Tetrahedron: Asymmetry 2007 Volume 18(Issue 22) pp:2668-2673

Publication Date(Web):12 November 2007

DOI:10.1016/j.tetasy.2007.10.040

The 1,3-aminophenol ligand (R)-1 was found to be a good catalyst for the zinc phenylacetylene addition to aldehydes. The high activity and enantioselectivity could be improved upon by basic additives. The enantioselectivity follows a linear free energy relationship with higher enantioselectivity obtained for the more reactive aryl aldehydes.(R)-1,3-Diphenyl-prop-2-yn-1-olC15H12OEe = 69%[α]D23=+3.2 (c 0.668, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(R)-1-(4-Nitrophenyl)-3-phenyl-prop-2-yn-1-olC15H11NO3Ee = 99%[α]D23=+13.3 (c 0.15, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(+)-1-(3-Nitrophenyl)-3-phenyl-prop-2-yn-1-olC15H11NO3Ee = 99%[α]D23=+9.4 (c 0.276, DCM)(−)-1-(2-Nitrophenyl)-3-phenyl-prop-2-yn-1-olC15H11NO3Ee = 36%[α]D23=-2.9 (c 0.34, DCM)(R)-1-(4-Methylphenyl)-3-phenyl-prop-2-yn-1-olC16H14OEe = 60%[α]D23=+2.2 (c 0.452, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(R)-1-(3-Methylphenyl)-3-phenyl-prop-2-yn-1-olC16H14OEe = 66%[α]D23=+2.8 (c 0.36, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(R)-1-(2-Methylphenyl)-3-phenyl-prop-2-yn-1-olC16H14OEe = 12%[α]D23=-3.6 (c 0.436, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(R)-1-(4-Chlorophenyl)-3-phenyl-prop-2-yn-1-olC15H11ClOEe = 88%[α]D23=+8.5 (c 0.4, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(R)-1-(3-Chlorophenyl)-3-phenyl-prop-2-yn-1-olC15H11ClOEe = 89%[α]D23=+9.8 (c 0.408, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(−)-1-(2-Chlorophenyl)-3-phenyl-prop-2-yn-1-olC15H11ClOEe = 88%[α]D23=-31.9 (c 0.514, DCM)(R)-1-(4-Bromophenyl)-3-phenyl-prop-2-yn-1-olC15H11BrOEe = 89%[α]D23=+3.9 (c 0.568, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(R)-1-(4-Methoxyphenyl)-3-phenyl-prop-2-yn-1-olC16H14O2Ee = 56%[α]D23=+0.9 (c 0.442, DCM)Source of chirality: alkynylationAbsolute configuration: (R)(R)-1,5-Diphenyl-pent-1-yn-3-olC17H16O2Ee = 22%[α]D23=-13.9 (c 0.458, CHCl3)Source of chirality: alkynylationAbsolute configuration: (R)(+)-1,4-Diphenyl-pent-1-yn-3-olC17H16OEe = 20%[α]D23=+15.5 (c 1.21, CHCl3)(+)-1,5-Diphenyl-pent-1-en-4-yn-3-olC17H14OEe = 36%[α]D23=+0.7 (c 0.722, CHCl3)(R)-2,4-Di-tert-butyl-6-(2,2-dimethyl-1-(methylamino)propyl)phenolC20H35NOEe >99%[α]D20=-31.7 (c 0.328, CH3COOCH2CH3)Source of chirality: (R)-2-(1-amino-2,2-dimethylpropyl)-4,6-di-tert-butylphenolAbsolute configuration: (R)

Resolution of β-aminoalcohols and 1,2-diamines using fractional crystallization of diastereomeric salts of dehydroabietic acid

Co-reporter:Zhang Guangyou, Liao Yuquing, Wang Zhaohui, Hiroyuki Nohira, Takuji Hirose

Tetrahedron: Asymmetry 2003 Volume 14(Issue 21) pp:3297-3300

Publication Date(Web):31 October 2003

DOI:10.1016/j.tetasy.2003.08.033

(S)-(+)-1-Amino-3-phenyloxy-2-propanol, (R)-(−)-2-amino-1-phenylethanol, (S)-(+)-1-amino-2-propanol, (1S,2S)-(+)-2-aminocyclohexanol and (1S,2S)-(+)-1,2-diaminocyclohexane were resolved using dehydroabietic acid. It was shown that good to high enantiomeric purity, between 81∼>99% ee, was obtained and that dehydroabietic acid could be easily and efficiently recovered in a reusable form.Dehydroabietic acid 1 showed good optical resolution ability towards four kinds of β-amino alcohols 2 and diaminocyclohexane giving 81∼>99% enantiomeric excess.Dehydroabietic acid 7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acidC20H28O2[α]D20=+62.5 (c 2.0, 95% ethanol)Source of chirality: natural sourceAbsolute configuration: (1S,4aS)(S)-(+)-1-Amino-3-phenyloxy-2-propanolC9H13NO2[α]D29=+2.4 (c 1.0, methanol)Source of chirality: resolutionAbsolute configuration: (S)(1S,2S)-(+)-2-AminocyclohexanolC6H13NO[α]D24=+8.2 (c 1.0, methanol)Source of chirality: resolutionAbsolute configuration: (1S,2S)

1H NMR study of chiral recognition of amines by chiral Kemp's acid diamide

Co-reporter:Takuji Hirose, Kumiko Naito, Hiroaki Shitara, Hiroyuki Nohira, Bruce W. Baldwin

Tetrahedron: Asymmetry 2001 Volume 12(Issue 3) pp:375-380

Publication Date(Web):5 March 2001

DOI:10.1016/S0957-4166(01)00066-0

Chiral recognition by homochiral Kemp's acid diamide was studied by a 1H NMR titration method. The diamide monoacid, prepared by amidation with enantiomerically pure (S)-α-methylbenzylamine, gave a large chemical shift change for five amines studied and showed good enantioselectivity toward cis-N-benzyl-2-aminocyclohexanemethanol.Chiral Kemp's acid diamide 1 showed large chemical shift changes for several chiral amines and was applied as a 1H NMR chiral shift reagent for cis-N-benzyl-2-aminocyclohexanemethanol.cis,cis-1,3,5-Trimethyl-3,5-bis[(S)-α-methylbenzylcarbamoyl]cyclohexane-1-carboxylic acidC28H36N2O4[α]D=−77.4 (c 1.0 EtOH)Source of chirality: (S)-(−)-α-methylbenzylamineAbsolute configuration: (3S,5S)

Efficient and practical organocatalytic system for the synthesis of cyclic carbonates from carbon dioxide and epoxides: 3-hydroxypyridine/tetra-n-butylammonium iodide

Co-reporter:Xiangyong Wang, Lin Wang, Yingying Zhao, Koichi Kodama, Takuji Hirose

Tetrahedron (23 February 2017) Volume 73(Issue 8) pp:1190-1195

Publication Date(Web):23 February 2017

DOI:10.1016/j.tet.2017.01.018

Cyanative self-condensation of aromatic aldehydes promoted by VO(OiPr)3–Lewis base as a cooperative catalyst

Co-reporter:Koichi Kodama, Hiroaki Kawamata, Naoya Takahashi and Takuji Hirose

Organic & Biomolecular Chemistry 2012 - vol. 10(Issue 47) pp:NaN9446-9446

Publication Date(Web):2012/10/17

DOI:10.1039/C2OB26811F

Solvent control of optical resolution of 2-amino-1-phenylethanol using dehydroabietic acid

Co-reporter:Kayoko Taniguchi, Marie Aruga, Mikio Yasutake and Takuji Hirose