Esters α-méthyléniques par substitution d'éthers et d'acétates dérivés de l'α-(hydroxyméthyl)acrylate d'éthyle
作者:Hassen Amri、Monique Rambaud、Jean Villiéras
DOI:10.1016/0022-328x(90)87047-h
日期:1990.2
α-(Methylene)alkanoic esters are prepared in high yields by substitution of α-(acetoxymethyl)acrylates using Grignard reagents in the presence of a catalytic amount of copper(I) salt. This reaction can be applied to lithium enolates of esters and ketones and to give functional α-(methylene) alkanoic esters, products of great interest for the synthesis of active biological compounds (sarkomycin, α-(methylene)
Synthesis of (E)-α,β-unsaturated esters with total diastereoselectivity by using chromium dichloride
作者:José M. Concellón、Humberto Rodrı́guez-Solla、Carmen Méjica
DOI:10.1016/j.tetlet.2004.02.011
日期:2004.3
Synthesis of di- and trisubstituted (E)-α,β-unsaturatedesters is easily achieved by using chromium dichloride through an elimination reaction of a diastereoisomeric mixture of α-halo-β-hydroxy esters. The starting materials were easily prepared by the aldol reaction of lithium enolates of α-chloroesters with aldehydes. A mechanism to explain this elimination process is proposed.