An enantioselective synthesis of (+)-polyoxamic acid via phase-transfer catalytic conjugate addition and asymmetric dihydroxylation.

A new enantioselective synthetic method of (+)-polyoxamic acid is reported. (+)-Polyoxamic acid could be obtained in 7 steps with 46% overall yield from diphenylmethyl-glycineimine tert-butyl ester via an enantioselective phase-transfer conjugate addition (99% yield, 96% ee) and an asymmetric dihydroxylation (98% yield, 94% de) as the key reactions.