Natural cyclopentanoid cyanohydrin glycosides, part 20 - Synthesis of epimers of L-cyclopentenylglycine using enzymatic resolution

Both epimers of the naturally occurring nonproteinogenic amino acid L-cyclo pentenylglycine, (2S,1'S)- and (2S,1'R)-2-(cyclopent-2'-enyl) glycine, were obtained via a procedure involving condensation of 3-chlorocyclopentene wi th diethyl acetylaminomalonate, deethoxycarbonylation, chromatographic sepa ration of the resulting two pairs of enantiomers, and enzymatic resolution of the racemates employing enantioselective hydrolysis of the ethyl ester g roup with cc-chymotrypsin. The method was used for preparation of C-13-labe led compounds of interest for biosynthetic tracer experiments. Enantiomeric purity of the products was determined by chiral HPLC on a Crown-pak CR(+) column. The biologically active (2S,1'R) isomer was obtained as a pure comp ound and characterized for the first time. The (2R,1'R) and (2R,1'S) isomer s were obtained as N-acetyl ethyl ester derivatives. Chirality 12:665-669, 2000. (C) 2000 Wiley-Liss, Inc.