Effect of the α-Methyl Substituent on Chemoselectivity in Esterase-Catalyzed Hydrolysis of <i>S</i>-Acetyl Sulfanylalkanoates
作者:Ish Kumar、Ravinder S. Jolly
DOI:10.1021/ol990544+
日期:1999.7.1
The isomeric compounds 1 and 3, which differ only in the position of a methyl substituent, give opposite chemoselectivities in an esterase-catalyzed hydrolysis reaction. The esterase was chemoselective for the oxoester in 1, but for the thiol ester group in 3. A high enantioselectivity was observed for both 1 and 3.
Evidence for α-lactone formation in the thioacetylation of some α-hydroxy acids with the aid of <i>Mitsunobu</i>
-type reagent
作者:Bert Strijtveen、Richard M. Kellogg
DOI:10.1002/recl.19871061006
日期:——
(S-Mandelic acid, (S)-lactic acid, and (S)-2-hydroxy-3-phenylpropionic acid react with thioacetic acid in the presence of the salt of diisopropyl azodicarboxylate and triphenylphosphine to give the α-(acetylthio)-substituted products. (S)-Mandelic acid reacts with predominant retention of configuration whereas (S)-lactic acid and (S)-2-hydroxy-3-phenylpropionic acid react predominantly with inversion