Synthesis of γ-Fluoro-α, β-unsaturated Carboxylic Esters from Saturated α-Fluoro Aldehydes
摘要:
gamma-Fluoro-alpha,beta-unsaturated carboxylic esters 7a, 7b and 7d and 4-fluoro-4-phenylbut-3-enoic ester (8) are obtained by two alternative pathways from 2-fluoro aldehydes 5a-d, either by Horner-Wadsworth-Emmons reaction or by Wittig reaction. The aldehydes 5a-d are prepared by Swern oxidation of the corresponding fluorohydrins 4a-d. These are available from alpha-olefins by bromofluorination, bromine-by-acetate replacement and subsequent hydrolysis.