A novel titanium tetrahalide-mediated carbon-carbon bond-forming reaction: regioselective synthesis of substituted (E,Z)-1,5-dihalo-1,4-dienes.
Reactions of aldehydes with 2 equiv of alkyne in the presence of TiX(4) (X = Cl, Br) regioselectively generated 1,5-dihalo-1,4-dienes in moderate to good yields with high (E,Z)-stereoselectivity. [reaction: see text]