In contrast, side-products from alkyne hydration were not observed with either internal or terminal aliphatic alkynes. Focusing on these substrates, we optimized the reaction temperature, solvent, reaction time, catalyst loading and absolute concentration for formation of the difluoroalkane product. Under the optimized conditions 1-fluoroheptane (2 equiv.) and 1-dodecyne (1 equiv.) react to form a mixture of internal heptene isomers (79%) and 2,2-difluorododecyne (76%) catalyzed by 10 mol% BF3-OEt2 in CHCl3 at 80 ºC (Figure ). A control reaction that omitted the 1-fluoroheptane gave <2% yield of the HF transfer product.