cis-chloropalladation of 1,6-enynes.

A PdCl(2)-catalyzed cis-chloropalladation-cyclization reaction of various 1,6-enyne substrates was developed. This Pd-catalyzed enyne cyclization reaction represents a new route for the synthesis of stereodefined alpha-halomethylene-gamma-butyrolactones, lactams, tetrahydrofurans, and cyclopentanes. A mechanism involving a neighboring coordination group is proposed to explain the experiment results.