Addition of acid chloride derivatives with alkynes is a useful reaction, affording β-chloroalkenyl ketones, which allow numerous synthetic applications, in particular, the synthesis of heterocyclic compounds.(1) These reactions have been made possible by using Lewis acids like AlCl 3 . However, as is anticipated by the use of Lewis acid catalysts, the major products are usually (E)-isomers with some exceptions forming mixtures of (E)- and (Z)-isomers(2) and the ...