Reactivity and selectivity of 1,3-diyn-6-enes in electrophilic transition metal-catalyzed reactions.

[Structure: see text] 1,3-diyne is an excellent source of alkynyl metal carbene species upon activation with an electrophilic metal catalyst. The products from this bond reorganization process suggest that the metal carbene species, generated from the preferential participation of an acetate over an alkene in the first step, undergo an efficient metallotropic [1,3]-shift followed by termination via cyclopropanation.