A Convenient Route to (R)-α-Hydroxy Carboxylic Acids and (2R)-1-Amino-2-alkanols from (R)-Cyanohydrins (R)-Cyanohyrins, prepared in good to excellent yields with high optical purity by enzyme-catalyzed addition of hydrogen cyanide to aldehydes in organic solvents, are hydrolyzed with concentrated hydrochloric acid at ambient temperature, usually in very high yield, without any trace of racemization to give (R)-α-hydroxy carboxylic acids. Likewise, no racemization is observed by direct reduction of the (R)-cyanohydrins with lithium aluminum hydride to give (2R)-1-amino-2-alkanols.
Chiral α‐functionalized carboxylic acids are valuable precursors for a variety of medicines and natural products. Herein, we described an engineered fatty acid photodecarboxylase (CvFAP)‐catalyzed kineticresolution of α‐aminoacids and α‐hydroxy acids, which provides the unreacted R‐configured substrates with high yields and excellent stereoselectivity (ee up to 99 %). This efficient light‐driven
Process for optically active 3-(methane-sulfonyloxy) thiolane and analogs
申请人:Pfizer Inc.
公开号:US04954647A1
公开(公告)日:1990-09-04
Intermediates and a stepwise process for the conversion of D-methionine or certain of its derivatives to optically active compounds of the formula ##STR1## wherein R is (C.sub.1 -C.sub.3)alkyl, phenyl or tolyl. The latter compounds are in turn useful as an intermediate in the preparation of penem antibiotic 5R,6S-6-(1R-hydroxyethyl)-2-(1R-oxo-3S-thiolanylthio)-2-penem-3-carboxylic acid and corresponding pharmaceutically acceptable salts and esters.
Process for optically active 3-(methane-sulfonyloxy)thiolane and analogs
申请人:Pfizer Inc.
公开号:US05326884A1
公开(公告)日:1994-07-05
Intermediates and a stepwise process for the conversion of D-methionine or certain of its derivatives to optically active compounds of the formula ##STR1## wherein R is (C.sub.1 -C.sub.3)alkyl, phenyl or tolyl. The latter compounds are in turn useful as an intermediate in the preparation of penem antibiotic 5R,6S-6-(1R-hydroxyethyl)-2-(1R-oxo-3S-thiolanylthio)-2-penem-3-carboxylic acid and corresponding pharmaceutically acceptable salts and esters.