Synthesis of dihalohydrins and tri- and tetra-substituted olefins

摘要

A novel synthesis reaction for highly stereospecific tri- and tetra-substituted olefins is described. A single stereoisomer of stable &agr;-halo-&agr;,&bgr;-ester is produced in high yield by the reaction of aldehyde or ketone with a trihalogenated compound such as trichloroacetate in the presence of CrCl₂ in a solvent. By varying the amount of CrCl₂ used, the stable dihalohydrin intermediate may be obtained as well.