Zobrazeno 1 - 10
of 143
pro vyhledávání: '"Masanori Utaka"'
Autor:
Yuji Wakasa, Takashi Sakai, Toshinobu Korenaga, Masanori Utaka, Minoru Fukumoto, Kunihiro Yamaguchi, Ryoichi Okada, Fumika Yano, Akinori Yabe, Tadashi Ema
Publikováno v:
Journal of Molecular Catalysis B: Enzymatic. 22:181-192
Lipases and subtilisins are versatile enzymes capable of showing high enantioselectivity and broad substrate specificity simultaneously. The transition-state models previously proposed to rationalize this important feature were intensively examined f
Publikováno v:
Tetrahedron. 57:3035-3044
Tricyclo[5.1.0.03,5]octane-2,6-diones 1a–q were prepared in moderate yields by the reaction of α,β-unsaturated esters 2 with dihalomethane in the presence of butyllithium, and by the reaction of dichloromethyl α,β-unsaturated ketones 3 with sod
Publikováno v:
ResearcherID
Large secondary alcohols, 5-[4-(1-hydroxyethyl)phenyl]-10,15,20-triphenylporphyrin ( 1a ) and the zinc complex 1b , designed on the basis of the transition-state model recently proposed by us, were subjected to the lipase-catalyzed transesterificatio
Publikováno v:
Tetrahedron: Asymmetry. 9:2681-2692
1-Chloro-2,4-alkanediones 1a – f prepared in one step were reduced using baker's yeast to afford 1-chloro-2-hydroxy-4-alkanones 2a – f regioselectively in S 29% to R 58% ee. Use of a small amount of organic solvents to dissolve the substrate enha
Publikováno v:
ResearcherID
The lipase-catalyzed kinetic resolution of (±)-2-acyloxy-2-(pentafluorophenyl)acetonitrile (±)- 1 gave optically active cyanohydrin (S)- 2 and its antipodal ester (R)- 1 ( E = 211), the former of which was transformed (TBSOTf, DMAP) into its TBS-et
Publikováno v:
The Journal of Organic Chemistry. 63:1102-1108
Reduction of 3-chloro-4-oxoalkanoates 5 with bakers' yeast gave (4S)-3-chloro-4-hydroxyalkanoates, which were hydrolyzed and dehydrochlorinated to give (γS)-alkylbutenolides with >96% ee. Reduction of 5 with NaBH4 gave syn-3-chloro-4-hydroxyalkanoat
Publikováno v:
ResearcherID
The stereoelectronic considerations and the molecular modeling using an X-ray structure of Rhizomucor miehei lipase suggested that the lipase-catalyzed reactions proceed under the stereoelectronic control. This suggestion was supported by the semiemp
Publikováno v:
ResearcherID
Efficient kinetic resolution of racemic 3-hydroxy-3-(pentafluorophenyl)- propionitrile (±)-1 by a lipase-catalyzed transesterification gave optically pure (S)-3-hydroxy-3-(pentafluorophenyl)-propionitrile (S)- 1 and (R)-(+)-3- acetoxy-3-(penta-fluor
Publikováno v:
ResearcherID
The effect of the acyl group of acylating agents on the enantioselectivity in the lipase-catalyzed transesterifications of racemic 2-[( N , N -dimethylcarbamoyl)methyl]-3-cyclopenten-1-ol in diisopropyl ether was found to be significant. The enantios
Publikováno v:
ResearcherID
The effect of the acyl group of acylating agents on the enantioselectivity in the Pseudomonas cepacia lipase-catalyzed acylations of racemic alcohols has been studied. 2-[(N,N-Dimethylcarbamoyl)met...