Hypervalent iodine(iii)-mediated ring-expansive difluorination of alkynylcyclopropanes en route to the synthesis of difluorinated alkylidenecyclobutanes

Described herein is a hypervalent iodine(iii)-mediated ring-expansive difluorination of alkynylcyclopropanes using commercially available Olah's reagent (HF center dot Py) as the fluorine source. The approach allows the facile synthesis of difluorinated alkylidenecyclobutanes with mild reaction conditions and moderate to good yields. Mechanistic studies suggest that the reaction occurs via regioselective 1,2-fluoroiodination of a triple bond followed by a Wagner-Meerwein-type rearrangement.

Automated summary

This study presents a new method for the synthesis of difluorinated alkylidenecyclobutanes through a hypervalent iodine(iii)-mediated reaction using commercially available Olah's reagent as the fluorine source. The reaction proceeds under mild conditions and provides moderate to good yields. Mechanistic investigations indicate that the reaction involves regioselective 1,2-fluoroiodination of a triple bond followed by a Wagner-Meerwein-type rearrangement.