Intramolecular cyclopropanation: stereospecific synthesis of (E)- and (Z)-1-aminocyclopropane-1-carboxylic acids
作者:Ari M. P. Koskinen、Luis Munoz
DOI:10.1021/jo00056a020
日期:1993.2
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 (20-40% overall from malonic acid) The free amino acids 12 and 18 can be liberated in two steps.