Reaction of thioglycolate with α-fluoro-β-(phenylthio)enones (or -enals): Synthesis of substituted α-carboxy-γ-fluorothiophenes

Article abstract of DOI:10.1016/S0040-4039(96)02509-9

A new synthetic method to substituted α-carboxy-γ-fluorothiophenes 2F is reported. They were prepared by the reaction between two equivalents of methyl thioglycolate anion and α-fluoro-β-(phenylthio)enones (or -enals) 1F, in DMSO (70°C) in yields ranging from 41% to 85%. We show from the reaction of (Z)-α-fluoro-β-(phenylthio)but-enone 1aF, that cyclisation to fluorothiophene 2aF occurs via the formation of stable enolates of α-fluoro-β-(dithianyl)butanone.