ASYMMETRIC-SYNTHESIS OF MOIRAMIDE-B

The first asymmetric synthesis. of Moiranide B 1 is achieved using lit hium amide 4 and pyrrolidinone auxiliary 5; pyrrolidinone auxiliary 5 is used to create the novel (S)-2-methyl-N-benzyloxysuccinimide 15 whi ch is subsequently acylated with the highly,reactive tert-butoxycarbon yl-protected N-carboxanhydride of L-valine(Boc-Val-NCA) under strongly basic conditions, without racemization, while lithium amide 4 is used to synthesize homochiral D-beta-phenylalanine tert-butyl ester 8.