The thio-Belluš-Claisen rearrangement with difluoroketene is reported herein. By resorting to fluoride-initiated desilylative β-elimination of difluorobromoacetylsilane, a new protocol that enables controlled release of the unstable difluoroketene and its efficient capture by allyl thioether for the ensuing rearrangement is successfully developed. The presence of an electron-withdrawing group on the internal alkene site of allyl thioether is proven to be vital for this reaction by promoting the rearrangement through charge stabilization in the transition state.
Xi et al. (2026) studied this question.