摘要:
Bromination of dehydroamino acid derivatives with NBS or Br2/2,6-lutidine yields (E)- or (Z)-beta-bromo-dehydroamino acid derivatives selectively. Subsequent intramolecular Michael addition-elimination of an aziridine proceeds with complete retention of olefin geometry to provide the 1-azabicyclo[3.1.0]hex-2-ylidene ring system proposed for the azinomycin series of antitumor antibiotics.