Intramolecular Cyclopropanation: Stereospecific Synthesis of (E)- and (Z)-1-Aminocyclopropane-1-carboxylic Acids

Article abstract of DOI:10.1021/jo00056a020

tert-Butyl-substituted allyl malonates, prepared in two steps from malonic acid, are diazotized in high yields.The diazomalonates 7 undergo a stereospecific copper(I)-catalyzed cyclopropanation to give 1-(tert-butoxycarbonyl)-3-oxa-2-oxobicyclo<3.1.0>hexanes 8 which can be converted to the protected (E)- or (Z)-1-aminocyclopropane-1-carboxylic acids 10 or 15 via Curtius- or Hoffmann-type rearrangements, respectively.The sequences are short (six steps from malonic acid) and proceed with good overall yields (20-40percent overall from malonic acid).The free amino acids 12 and 13 can be liberated in two steps.