SYNTHESIS OF ALL 4 HOMOCHIRAL STEREOISOMERS OF METHYL 3-PHENYL-1H-AZIRIDINE-2-CARBOXYLATE

Sodium -E3-phenylglycidate (±)-2E was prepared using the Darzens' procedure. Classical resolution with 1-phenylethylamine afforded optically pure salts (+)-(2S,3R)-2E and (-)-(2R,3S)-2E. Alternatively, (±)-2E was converted into (±)-2Z by ring opening of ethyl ester (±)1E with hydrogen bromide, followed by recyclization and saponification. Classical resolution of (±)-2Z with ephedrine afforded optically pure salts (+)-(2S,3S)-2Z and (-)-(2R,3R)-2Z Treatment of the four sodium salts with sodium azide followed by esterification gave hydroxy azido esters 3, which were finally converted into the four homochiral stereoisomers of methyl 3-phenyl-1H-aziridine-2-carboxylate 5 in a reaction with triphenylphosphine and subsequent heating of the initially formed oxazaphospholidines 4. © 1990.