Regio- and Stereoselective Hydrochlorination/Cyclization of 1, n -Enynes by FeCl 3 Catalysis.

A highly regio- and stereoselective hydrochlorination/cyclization of enynes has been reported by FeCl 3 catalysis. A variety of enynes undergo this cyclization transformation with acetic chloride as the chlorine source and H 2 O providing protons via a cationic pathway. This protocol provides a cheap, simple, stereospecific, and effective cyclization to afford heterocyclic alkenyl chloride compounds as Z isomers with high yields (≤98%) and regioselectivity.