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Chemo‐ and Stereoselective Reduction of β‐Keto‐α‐oximino Nitriles by Using Baker's Yeast
Author(s) -
Mo Kilwoong,
Kang Soon Bang,
Kim Youseung,
Lee Yong Sup,
Lee Jae Wook,
Keum Gyochang
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201403393
Subject(s) - chemistry , nitrile , stereoselectivity , enantiomer , yield (engineering) , oxime , hydrolysis , enantiomeric excess , alcohol , yeast , organic chemistry , proton nmr , stereochemistry , enantioselective synthesis , catalysis , biochemistry , materials science , metallurgy
Abstract The baker's yeast mediated reduction of β‐keto‐α‐oximino nitriles 3 at 20 °C gave β‐hydroxy‐α‐oximino nitriles 4 in high yields with high enantiomeric purity [enantiomeric excess ( ee ) values >99 %]. At room temperature, the same reaction afforded the product in a slightly lower yield. The β‐hydroxy‐α‐oximino nitriles 4 were obtained as single stereoisomers according to chiral GC–MS analyses and the 1 H and 19 F NMR spectra of the corresponding Mosher esters. The absolute stereochemistry of alcohol 4a was determined by hydrolysis of its oximino nitrile group followed by conversion into its corresponding α‐hydroxy ester. The β‐hydroxy‐α‐oximino nitrile products were further submitted to oxime‐ and nitrile‐selective transformations. This chemo‐ and stereoselective reduction can be used to generate important chiral building blocks.