Synthesis of hydrohalocyclobutenes through dechlorination of hydrohalocyclobutanes in amide solvents

In this study, we synthesized hydrohalocyclobutenes through the dechlorination of hydrohalocyclobutanes in N,N-dimethylformamide and N,N-dimethylacetamide. The structure of the reaction site −CClR¹−CClR²– (R¹ = H, F; R² = H, F, Cl) of the reactants was critical for the efficient reductive dechlorination from the 1- and 2- positions. The reaction proceeded efficiently at the –CFCl–CFCl–, –CFCl−CCl₂–, and −CHCl−CHCl– groups. Conversely, the –CFCl−CHCl– group could hardly afford the dechlorinated product. Based on these results, we propose a rational reaction mechanism.