64363-89-9Relevant academic research and scientific papers
CATALYTIC ASYMMETRIC SYNTHESIS OF OPTICALLY ACTIVE α-HALO-CARBONYL COMPOUNDS
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Page/Page column 21-22, (2010/02/13)
A process for the catalytic asymmetric synthesis of an optically active compound of the formula (la) or (lb): wherein R is an organic group; X is halogen; Rland R2which may the same or different represents H, or an organic group or R
Enantioselective protonation of silyl enol ethers and ketene disilyl acetals with Lewis acid-assisted chiral Bronsted acids: Reaction scope and mechanistic insights
Nakamura, Shingo,Kaneeda, Masanobu,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 8120 - 8130 (2007/10/03)
Enantioselective protonation is a potent and efficient way to construct chiral carbons. Here we report details of the reaction using Lewis acid-assisted chiral Bronsted acids (chiral LBAs). The 1:1 coordinate complex of tin tetrachloride and optically active binaphthol ((R)- or (S)-BINOL) can directly protonate various silyl enol ethers and ketene disilyl acetals to give the corresponding α-aryl ketones and α-arylcarboxylic acids, respectively, with high enantiomeric excesses (up to 98% ee). A catalytic version of enantioselective protonation has also been achieved using stoichiometric amounts of 2,6-dimethylphenol and catalytic amounts of monomethyl ether of optically active BINOL in the presence of tin tetrachloride. This protonation is also effective for producing α-halocarbonyl compounds (up to 91% ee). DFT calculations on the B3LYP/LANL2DZ level show that the conformational structure of the chiral LBA and the orientation of activated proton on (R)-BINOLs are important for understanding the absolute stereochemistry of the products.
ENZYMATIC "IN VITRO" REDUCTION OF KETONES : Part 9. Preparation of pure (1S,2S)-2-chlorocyclohexanol.
Sadozai, S. K.,Merckx, E. M.,Wal, A. J. Van de,Lemiere, G. L.,Esmans, E. L.,et al.
, p. 163 - 170 (2007/10/02)
The enzymatic "in vitro" reduction of 2-chlorocyclohexanone in a coupledsubstrate coenzyme recycling system (ketone - ethanol - NAD+ - HLAD) delivers optically pure (1S,2S)-2-chlorocyclohexanol.The optical purity is shown by (19)F-NMR of the (R
