Masahiko Hayashi

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Organization: Kobe University , Japan

Department: Department of Chemistry

Title: (PhD)

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Organic Chemistry

Chemicals
References

Synthesis of Enantiomerically Pure (8S,9S,10R,6Z)-Trihydroxyoctadec-6-enoic Acid

Co-reporter:Jogula Srinivas, Yoichi Namito, Ryosuke Matsubara, and Masahiko Hayashi

The Journal of Organic Chemistry May 19, 2017 Volume 82(Issue 10) pp:5146-5146

Publication Date(Web):April 13, 2017

DOI:10.1021/acs.joc.7b00376

We have accomplished the asymmetric synthesis of (8S,9S,10R,6Z)-trihydroxyoctadec-6-enoic acid in optically pure form and determined the absolute configuration of the natural product on the basis of the stereodetermined chiral building block 7, which was prepared by the catalytic enantioselective allylic oxidation of 4,5-epoxycyclohex-1-ene using an S-configured N,N-bidentate ligand–copper catalyst.

Recent topics on catalytic asymmetric 1,4-addition

Co-reporter:Masahiko Hayashi, Ryosuke Matsubara

Tetrahedron Letters 2017 Volume 58, Issue 19(Issue 19) pp:

Publication Date(Web):10 May 2017

DOI:10.1016/j.tetlet.2017.03.044

•Catalytic asymmetric 1,4-addition is a powerful method for carbon-carbon bond formation.•Combination of copper and chiral ligand with organometallic reagents have been developed.•Unique phenomena that include the nonlinear effect and reversal of enantioselectivity.•Synthesis of natural products using catalytic asymmetric 1,4-addition have been demonstrated.Catalytic asymmetric 1,4-addition (conjugate addition; Michael addition) is one of the most powerful methods for carbon-carbon bond formation. Following the first efficient catalyst system developed by Feringa, which is composed of Cu(OTf)2 and phosphoramidite with dialkylzincs, a variety of chiral catalysts have been reported for the catalytic asymmetric conjugate addition. In this digest review, we will first summarize novel chiral ligands that work efficiently for cyclic and acyclic enones and demonstrate the wide applicability of Michael acceptors. We will also introduce unique phenomena that include the nonlinear effect and reversal of enantioselectivity. Organomagnesium reagents have also been used instead of organozincs. Finally, we introduce the recent examples of the synthesis of natural products based on the catalytic asymmetric reaction. The rare experimental studies into the mechanism of copper-catalyzed 1,4-addition reported by Kitamura and Noyori’s group are also introduced.Download high-res image (80KB)Download full-size image

Dehydrogenative Formation of Resorcinol Derivatives Using Pd/C–Ethylene Catalytic System

Co-reporter:Ibrahim Yussif El-Deeb, Tatsuya Funakoshi, Yuya Shimomoto, Ryosuke Matsubara, and Masahiko Hayashi

The Journal of Organic Chemistry 2017 Volume 82(Issue 5) pp:

Publication Date(Web):February 7, 2017

DOI:10.1021/acs.joc.6b03037

The conversion of substituted 1,3-cyclohexanediones to the alkyl ethers of resorcinol using a Pd/C–ethylene system is reported. In these reactions, ethylene works as a hydrogen acceptor. The efficient synthesis of resveratrol was achieved using this protocol as a key step. In addition, the direct formation of substituted resorcinols was carried out by adding K2CO3 into the reaction media.

Selective Synthesis of Partially Protected d-Talopyranosides and d-Gulopyranosides via Catalytic Asymmetric Dihydroxylation: Multiplier Effects of Substrate Control and Catalyst Control

Co-reporter:Yoichi Namito, Kyosuke Michigami, Takaaki Nagahashi, Ryosuke Matsubara, and Masahiko Hayashi

Organic Letters 2016 Volume 18(Issue 23) pp:6058-6061

Publication Date(Web):November 11, 2016

DOI:10.1021/acs.orglett.6b03000

Highly selective syntheses of d-talopyranosides and d-gulopyranosides have been achieved by utilizing the multiplier effects of substrate control and catalyst control. Through the combination of an O-benzoyl-protected substrate and the AD-mix-β system, the d-talopyranoside was obtained in a ratio of 96:4. In contrast, the d-gulopyranoside was obtained in a ratio of 3:97 through the use of an O-tert-butyldimethylsilyl-protected substrate and AD-mix-α.

Asymmetric Synthesis of cis- and trans-2-Aryl-6-methylpyrans from D-Glucose by Arylation and Inversion of Configuration at the C-2 Position

Co-reporter:Kyosuke Michigami;Atsuko Shimazaki

European Journal of Organic Chemistry 2014 Volume 2014( Issue 1) pp:

Publication Date(Web):

DOI:10.1002/ejoc.201301376

Abstract

Asymmetric synthesis of optically active cis- and trans-2-aryl-6-methylpyrans from commercially available tetra-O-acetyl-D-glucopyranosyl bromide has been developed. The reaction proceeds by two important steps. One is the arylation, and the other is deoxygenation at the C-3 position and inversion of configuration at the C-2 position during the preparation of the cis-isomer, when 2-aryl-3-hydroxy-6-(hydroxymethyl)pyrans were treated with trimethylsilyl chloride and sodium iodide.

Enantioselective alkylation of aldehydes using dialkylzincs catalyzed by simple chiral diols derived from naturally occurring monosaccharides

Co-reporter:Kyosuke Michigami, Masahiko Hayashi

Tetrahedron 2013 69(21) pp: 4221-4225

Publication Date(Web):

DOI:10.1016/j.tet.2013.03.090

Practical preparation of chiral keto-imine type ONO Schiff base ligands

Co-reporter:Vasudevan Dhayalan, Ryo Murakami, Masahiko Hayashi

Tetrahedron: Asymmetry 2013 Volume 24(9–10) pp:543-547

Publication Date(Web):31 May 2013

DOI:10.1016/j.tetasy.2013.03.017

A practical preparation of chiral keto-imine type ONO Schiff base ligands has been reported. Metal complexes of these Schiff bases work as efficient chiral catalysts in a variety of asymmetric reactions.(S,E)-2,4-Di-tert-butyl-6-1-(1-hydroxy-3-methylbutan-2-ylimino)ethylphenolC21H33NO2Ee = >99%[α]D24 = -30.4 (c 1.0, CHCl3)Source of chirality: (S)-amino acidAbsolute configuration: (S)(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3-methylbutan-2-ylimino)phenylmethylphenolC26H35NO2Ee = >99%[α]D24 = -30.5 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3,3-dimethylbutan-2-ylimino)phenyl-methylphenolC27H37NO2Ee = >99%[α]D24 = -34.1 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3,3-dimethylbutan-2-ylimino)p-tolyl-methylphenolC28H41NO2Ee = >99%[α]D24 = -38.7 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)(S,E)-2,4-Di-tert-butyl-6-(4-tert-butylphenyl)(1-hydroxy-3,3-dimethylbutan-2-ylimino)methylphenolC31H47NO2Ee = >99%[α]D24 = -33.7 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)(S,E)-2-3,5-Bis(trifluoromethyl)phenyl-(1-hydroxy-3-methylbutan-2-ylimino)methyl-4,6-di-tert-butylphenolC28H35F6NO2Ee = >99%[α]D24 = -7.3 (c 1.0, CHCl3)Source of chirality: (S)-amino acidAbsolute configuration: (S)(S,E)-2-3,5-Bis(trifluoromethyl)phenyl-(1-hydroxy-3,3-dimethylbutan-2-ylimino)methyl-4,6-di-tert-butylphenolC29H37F6NO2Ee = >99%[α]D24 = -8.1 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3-methylbutan-2-ylimino)(4-trifluoromethylphenyl)methylphenolC21H36F3NO2Ee = >99%[α]D24 = -15.6 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)(S,E)-2,4-Di-tert-butyl-6-(1-hydroxy-3-methylbutan-2-ylimino)(3,4,5-trifluorophenyl)methylphenolC26H34F3NO2Ee = >99%[α]D24 = -13.8 (c 1.0, CHCl3)Source of chirality: (S)-aminoacidAbsolute configuration: (S)

Synthesis of novel nucleosides and stereoselectivity of N-glycosidation

Co-reporter:Kyosuke Michigami, Satoshi Uchida, Miho Adachi, Masahiko Hayashi

Tetrahedron 2013 69(2) pp: 595-599

Publication Date(Web):

DOI:10.1016/j.tet.2012.11.017

Facile synthesis of acacetin-7-O-β-d-galactopyranoside

Co-reporter:James T. Zacharia, Masahiko Hayashi

Carbohydrate Research 2012 Volume 348() pp:91-94

Publication Date(Web):1 February 2012

DOI:10.1016/j.carres.2011.11.015

Acacetin-7-O-β-d-galactopyranoside (1), a natural flavonoid isolated from flower heads of Chrysanthemum morifolium, has been reported to inhibit the replication of HIV in H9 cells. We achieved the total synthesis of compound 1 by employing a one-pot synthesis of the aglycon. The key reactions in this approach include the modified Baker–Venkataraman reaction and regio- and stereoselective O-glycosylations.Graphical abstractHighlights► Acacetin-7-O-β-d-galactopyranoside (1), has been reported to inhibit the replication of HIV. ► Total synthesis of compound 1 employing a one-pot synthesis of aglycon. ► The key reaction in this approach includes the regio- and stereoselective O-glycosylation.

O- and N-Glycosidation of d-glycals using Ferrier rearrangement under Mitsunobu reaction conditions. Application to N-nucleoside synthesis

Co-reporter:Kyosuke Michigami, Masahiko Hayashi

Tetrahedron 2012 68(4) pp: 1092-1096

Publication Date(Web):

DOI:10.1016/j.tet.2011.11.084

Enantioselective copper-catalyzed 1,4-addition of dialkylzincs to enones using a novel N,N,P–Cu(II) complex

Co-reporter:Yasuhiro Ebisu, Kenjiro Kawamura, Masahiko Hayashi

Tetrahedron: Asymmetry 2012 Volume 23(Issue 13) pp:959-964

Publication Date(Web):15 July 2012

DOI:10.1016/j.tetasy.2012.06.010

Enantioselective copper-catalyzed 1,4-additions of dialkylzincs to enones were carried out in the presence of 1 mol % of Cu(OTf)2 and 2.5 mol % of an N,N,P-ligand possessing a tert-butyl group at the adjacent position of the nitrogen of pyridine to afford the corresponding 1,4-adducts in up to 98% ee.(S,E)-N-((4,6-Di-tert-butylpyridin-2-yl)methylene)-1-(diphenylphosphino)-3,3-dimethylbutan-2-amineC32H43N2PEe = 99%[α]D24=+81.3 (c 1.0, CHCl3)Source of chirality: (S)-amino acidAbsolute configuration: (S)(S)-(−)-3-Ethylcyclopentan-1-oneC7H12OEe = 98%[α]D24=-50.1 (c 0.8, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)(S)-(−)-3-Methylcyclohexan-1-oneC7H12OEe = 98%[α]D24=-6.6 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)(S)-(−)-3-Ethylcyclohexan-1-oneC8H14OEe = 97%[α]D24=-10.0 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)(S)-(−)-3-Methylcycloheptan-1-oneC8H14OEe = 92%[α]D24=-62.0 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)(S)-(−)-3-Ethylcycloheptan-1-oneC9H16OEe = 80%[α]D24=-50.4 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)(R)-(−)-1,3-Diphenylpentan-1-oneC17H12OEe = 83%[α]D24=-2.0 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)(R)-(−)-3-(4-Methoxyphenyl)-1-phenylpentan-1-oneC18H20O2Ee = 75%[α]D24=-5.8 (c 1.1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)(R)-(−)-3-(4-Nitrophenyl)-1-phenylpentan-1-oneC17H17NO3Ee = 85%[α]D24=+22.1 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)(R)-(−)-3-(4-Fluorophenyl)-1-phenylpentan-1-oneC17H17FOEe = 85%[α]D24=-2.5 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)(R)-(−)-3-(2,6-Dimethylphenyl)-1-phenylpentan-1-oneC19H22OEe = 79%[α]D24=-23.0 (c 1.1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

A facile synthesis of (1S,5R,6S)-5-azido-6-benzyloxycyclohex-2-en-1-ol

Co-reporter:Takanori Tanaka, Qitao Tan, Kazunari Iwanaga, Masahiko Hayashi

Carbohydrate Research 2011 Volume 346(Issue 2) pp:340-342

Publication Date(Web):1 February 2011

DOI:10.1016/j.carres.2010.11.012

A facile and short synthesis of (1S,5R,6S)-5-azido-6-benzyloxycyclohex-2-en-1-ol (1) has been achieved in high yield starting from 4,5-epoxycyclohex-1-ene by using a catalytic asymmetric allylic oxidation reaction.

Formal Total Synthesis of (−)-Oseltamivir Phosphate

Co-reporter:Takanori Tanaka, Qitao Tan, Hiromu Kawakubo, and Masahiko Hayashi

The Journal of Organic Chemistry 2011 Volume 76(Issue 13) pp:5477-5479

Publication Date(Web):May 31, 2011

DOI:10.1021/jo200698g

An asymmetric synthesis of chiral intermediate 3 for (−)-oseltamivir phosphate has been accomplished from chiral building block 1, which was prepared by catalytic asymmetric synthesis.

Oxidative transformation of thiols to disulfides promoted by activated carbon–air system

Co-reporter:Masahiko Hayashi, Ken-ichi Okunaga, Shunsuke Nishida, Kenjiro Kawamura, Kazuo Eda

Tetrahedron Letters 2010 Volume 51(Issue 51) pp:6734-6736

Publication Date(Web):22 December 2010

DOI:10.1016/j.tetlet.2010.10.070

Efficient oxidative transformation of thiols to disulfides took place in the presence of activated carbon under an oxygen (or air) atmosphere. The present oxidation method is available not only for a variety of thiols such as simple aromatic and aliphatic thiols but also for 3,4-dihydropyrimidin-2(1H)-thiones and N-Boc-l-cysteine.

Dehydrogenation of 1,2,3,4-tetrahydroquinoline and its related compounds: comparison of Pd/C–ethylene system and activated carbon–O2 system

Co-reporter:Takanori Tanaka, Ken-ichi Okunaga, Masahiko Hayashi

Tetrahedron Letters 2010 Volume 51(Issue 35) pp:4633-4635

Publication Date(Web):1 September 2010

DOI:10.1016/j.tetlet.2010.06.118

Dehydrogenation of substituted 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline, and 1,2,3,4-tetrahydrocarbazole proceeded using Pd/C–ethylene system (method A) or activated carbon–O2 system (method B) to give the corresponding heteroaromatic compounds.

Effect of ortho-substituents on the stereochemistry of 2-(o-substituted phenyl)-1H-imidazoline–palladium complexes

Co-reporter:Zhibin Gan, Kenjiro Kawamura, Kazuo Eda, Masahiko Hayashi

Journal of Organometallic Chemistry 2010 695(17) pp: 2022-2029

Publication Date(Web):

DOI:10.1016/j.jorganchem.2010.05.007

Asymmetric Desymmetrization of 4,5-Epoxycyclohex-1-ene by Enantioselective Allylic Oxidation

Co-reporter:Qitao Tan and Masahiko Hayashi

Organic Letters 2009 Volume 11(Issue 15) pp:3314-3317

Publication Date(Web):July 6, 2009

DOI:10.1021/ol901284v

Asymmetric desymmetrization of allylic oxidation of 4,5-epoxycyclohex-1-ene (1) took place in the presence of 2.5 mol % of Cu(CH3CN)4PF6 and 3 mol % of chiral N,N-bidentate ligand (S)-2 to afford (3S,4S,5S)-3-benzoyloxy-4,5-epoxycyclohex-1-ene (3) in 84% ee, which was increased up to >99% ee after recrystallization of 3-4′-nitrobenzoyloxy derivative 6. Optically pure 6 proved to be a key intermediate for enantioselective synthesis of O-protected 2-deoxystreptamine (2-DOS) precursor 12.

Copper(I)-2-(2′-pyridyl)benzimidazole catalyzed N-arylation of indoles

Co-reporter:Satoshi Haneda, Yusuke Adachi, Masahiko Hayashi

Tetrahedron 2009 65(50) pp: 10459-10462

Publication Date(Web):

DOI:10.1016/j.tet.2009.10.014

Novel N,N-Bidentate Ligands for Enantioselective Copper(I)- Catalyzed Allylic Oxidation of Cyclic Olefins

Co-reporter:Qitao Tan

Advanced Synthesis & Catalysis 2008 Volume 350( Issue 16) pp:2639-2644

Publication Date(Web):

DOI:10.1002/adsc.200800457

Abstract

New N,N-bidentate Schiff base ligands containing the 2-quinolyl moiety proved to be effective in conferring high reactivity and moderate to high enantioselectivity (up to 84% ee) to the copper(I)-catalyzed asymmetric allylic oxidation of various cylic olefins with tert-butyl perbenzoate. As copper(I) sources, we employed copper(II) triflate/phenylhydrazine [Cu(OTf)₂/PhNHNH₂] and tetra(acetonitrile)copper hexafluorophosphate [Cu(CH₃CN)₄PF₆]. Using the same N,N-bidentate Schiff base ligand, the former showed high reactivity and the latter showed high enantioselectivity.

Chiral Schiff Bases as Highly Active and Enantioselective Catalysts in Catalytic Addition of Dialkylzinc to Aldehydes

Co-reporter:Takanori Tanaka;Yuki Sano

Chemistry – An Asian Journal 2008 Volume 3( Issue 8-9) pp:1465-1471

Publication Date(Web):

DOI:10.1002/asia.200800132

Abstract

We have developed chiral Schiff base catalysts based on the ONO-tridentate ligand for the catalytic enantioselective addition of dialkylzinc to aldehydes. Various aldehydes were smoothly converted into corresponding optically active secondary alcohols with high enantioselectivity (up to 98 % ee) in high yield. Furthermore, we have succeeded in decreasing the catalyst loading minimum to 0.1 mol % in the chiral Schiff base-catalyzed enantioselective alkylation of aldehydes.

Oxidation using activated carbon and molecular oxygen system

Co-reporter:Masahiko Hayashi

The Chemical Record 2008 Volume 8( Issue 4) pp:252-267

Publication Date(Web):

DOI:10.1002/tcr.20152

Abstract

This paper describes the utility of an activated carbon–molecular oxygen system, not only in the oxidation of benzylic and allylic alcohols, but also in the direct carbonylation at the benzylic position. The preparation of a variety of heteroaromatic and aromatic compounds, including substituted pyridines, pyrazoles, benzoxazoles, benzimidazoles, benzothiazoles, 2-substituted imidazoles, indoles, pyrimidin-2(1H)-ones, and anthracenes, by oxidative aromatization using the activated carbon–molecular oxygen system is also discussed. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 252–267; 2008: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20152

2-Phenylimidazole−PdCl2 and 2-Phenylimidazoline−PdCl2 Complexes: Single-Crystal and Powder X-ray Diffractometry, 1H NMR Spectra, and Comparison of Catalytic Activities in Coupling Reactions†

Co-reporter:Kenjiro Kawamura ; Satoshi Haneda ; Zhibin Gan ; Kazuo Eda

Organometallics 2008 Volume 27(Issue 15) pp:3748-3752

Publication Date(Web):July 16, 2008

DOI:10.1021/om800230y

Single-crystal X-ray diffractometry and powder X-ray diffractometry of the complexes dichlorobis(2-phenyl-1H-imidazole)palladium(II) (1) and dichlorobis(2-phenyl-4,5-dihydro-1H-imidazole)palladium(II) (2) and 1H NMR structure elucidation in DMF-d7 solution are discussed. In the case of complex 1, we found that changing the solvent for recrystallization from a mixture of DMF and toluene (method A) to only DMF (method B) afforded complexes 2 and 2′, having crystallographically different structures. 1H NMR studies indicated that the spectra of the solid samples 2 and 2′ are the same in DMF-d7. This indicated that the Pd−N bond rotates easily in solution, whereas complexes 2 and 2′ coexist through strong packing in the solid state. The catalytic activities of Pd complexes 1 and 2 in coupling reactions such as the Mizoroki−Heck reaction and Suzuki−Miyaura coupling will also be disclosed.

Imidazole and Imidazoline Derivatives as N-Donor Ligands for Palladium-Catalyzed Mizoroki–Heck Reaction

Co-reporter:Satoshi Haneda;Chigusa Ueba;Kazuo Eda

Advanced Synthesis & Catalysis 2007 Volume 349(Issue 6) pp:

Publication Date(Web):17 APR 2007

DOI:10.1002/adsc.200600364

Imidazole and imidazoline (dihydroimidazole) derivatives can serve as efficient and simple ligands for the palladium-catalyzed Mizoroki–Heck reaction. Among the imidazole and imidazoline derivatives in our investigations, the 2-methylimidazoline-palladium(II) chloride complex exhibited the highest catalytic activity.

Ligand Effects of 2-(2-Pyridyl)benzazole−Pd Complexes on the X-ray Crystallographic Structures, 1H NMR Spectra, and Catalytic Activities in Mizoroki−Heck Reactions

Co-reporter:Satoshi Haneda, Zhibin Gan, Kazuo Eda and Masahiko Hayashi

Organometallics 2007 Volume 26(Issue 26) pp:6551-6555

Publication Date(Web):November 27, 2007

DOI:10.1021/om7008843

A series of PdCl2 complexes were synthesized using four 2-(2-pyridyl)benzazoles, namely 2-(2-pyridyl)benzimidazole (1a), 2-(2-pyridyl)benzoxazole (2a), 2-(2-pyridyl)benzothiazole (3a), and 2-(2-pyridyl)-N-methylbenzimidazole (4a). Their structures were analyzed using single X-ray crystallography, whereas the extent of the ligand dissociation were determined in solution by 1H NMR spectroscopy. Among the catalysts, 2-(2-pyridyl)benzimidazole−PdCl2 (1b) complex exhibited the highest catalytic activity toward the Mizoroki−Heck reaction: the diminished catalytic activities of 2-(2-pyridyl)benzoxazole−PdCl2 (2b) and 2-(2-pyridyl)benzothiazole−PdCl2 (3b) can be attributable to the ease of their ligand dissociation.

Stereoselective C-glycosidation of unprotected D-glycals with trimethylsilyl cyanide

Co-reporter:Masahiko Hayashi;Shu-Zo Nakayama;Hirotoshi Kawabata

Chirality 2003 Volume 15(Issue 1) pp:10-16

Publication Date(Web):20 NOV 2002

DOI:10.1002/chir.10146

Unprotected glycals reacted with trimethylsilyl cyanide in the presence of a catalytic amount of a palladium compound to yield the 2,3-unsaturated glycosyl cyanides in high yield and in α-selectivity. Chirality 15:10–16, 2003. © 2002 Wiley-Liss, Inc.

Enantioselective addition Of diketene to aldehydes promoted by chiral schiff base—titanium alkoxide complex. Application to asymmetric synthesis of potential inhibitors of HMG coenzyme reductase

Co-reporter:Kiyoshi Tanaka;Nobuki Oguni;Naohito Hirata;Kazuya Yoshimoto;Akio Matsushita;Hiroshi Sasaki;Katsumasa Harada;Yasuhiro Kawachi

Israel Journal of Chemistry 2001 Volume 41(Issue 4) pp:241-246

Publication Date(Web):8 MAR 2010

DOI:10.1560/PX53-Y9JJ-FU8V-GKEN

Highly enantioselective addition of diketene to aldehydes was achieved by using novel Schiff base—titanium alkoxide complexes. Up to 92% ee of 5-hydroxy-3-oxoesters was obtained. This procedure provides an efficient method for the asymmetric synthesis of potential inhibitors of HMG coenzyme reductase.