α-Bromo-α, α-difluoroallyl Derivatives as Synthetic Intermediate : Nucleophilic Substitution of α-Bromo-α, α-difluoroally Derivatives in the Presence of Palladium Catalysts

Abstract

The palladium catalyzed nucleophilic substitution ofα-bromo-α, α-difluoroallyl derivatives turned out to be an efficient method for the preparation of several fluorinated organic molecules. Several soft carbon nucleophiles regioselectively reacted with 3-bromo-3, 3-difluoropropene (BDFP) to give the 3-substituted 1, 1-difluoroalkenes. Phenylzinc chloride and tributylphenyltin afforded 1-fluoro-1, 3-diphenylpropene. The radical bromination of 3-substituted 1, 1-difluoroalkenes provided 1-substituted BDFPs, and a 1-substituted BDFP reacted with carbon nucleophiles to give 1, 3-disubstituted 3, 3-difluoroalkenes. For the reaction of nitrogen nucleophiles with BDFP, an amine and the sodium salts of the carbamates reacted with BDFP at the γ-position. However, the sodium salts of the sulfoneamide predominantly attacked at the α-position.