New zirconium-mediated approach toward regio- and stereocontrolled synthesis of trans-enediynes.

[reaction: see text] The coupling reactions of alpha-alkynylated zirconacyclopentene based on 1,4-bis(trimethylsilyl)-1,3-butadiyne with unsaturated compounds are described, which provide an efficient, regio- and stereocontrollable synthesis of trans-enediynes in a one-pot procedure. An interesting alkynyl group shift from alpha- to beta-position of the zirconium center during the reaction was observed, which was accountable for the novel transformations to trans-enediynes.