the presence of a base did not give the expected esters but 2-chloro-1,1-difluoroprop-2-enyl methanesulfonates (4) through a novel [3,3] sigmatropic rearrangement. Reaction of 4 with diethylzinc in the presence of tetrakis(triphenylphosphine) palladium gave 1-alkyl- or 1-aryl-2-chloro-3-fluoropenta-1,3-dienes in moderate to good yields through a CC bond formation followed by dehydrofluorination.
We have reported the Grignard reaction of Halothane, 2-bromo-2-chloro-1,1,1-trifluoroethane (1), with ketones gave unexpected products, α-(1-bromo-1-chloro-2,2,2-trifluoroethyl)alcohols (4) at a low temperature. However, this reaction hardly proceeded with aldehydes. Now, we found the reaction of 1 with aldehydes in the presence of zinc gave not only products of type 4, but α-(1-chloro-2,2,2-trifluoroethyl)alcohols