Regioselective alkylzirconation of internal alkynes

Described herein is the carbometallation of unsymmetrically 1,2-disubstituted alkynes with alkylzirconocene complexes, which are generated by hydrozirconation of alkenes. High regioselectivity is achieved when the two substituents of the alkynes are sterically different enough, giving rise to the regio- and stereodefined trisubstituted alkenes.