Palladium-Catalyzed Regio- and Stereoselective Formate Reduction of Fluorine-Containing Allylic Mesylates. A New Entry for the Construction of a Tertiary Carbon Attached with a Fluoroalkyl Group
regioselective palladium-catalyzed formate reduction of γ-fluoroalkylated allylic esters is described. Reduction of the allylic esters under the influence of palladium with a monodentate phosphine ligand proceeded preferentially at the γ position, the corresponding reduction products with a fluoroalkyl group at the tertiary carbon being afforded in high yields. When the chiral allylic ester was employed
hydrodefluorination reaction of trifluoromethylated alkenes to access terminal monofluoroalkenes. The use of LiAlH4 allowed the stereoselectivesynthesis of the terminal monofluoroalkenes in good to excellent yields with good to excellent diastereoselectivities. Mechanistic studies suggested a hydroalumination reaction followed by a stereoselective fluoride elimination.