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

摘要

The palladium catalyzed nucleophilic substitution of α-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.