Rhodium-Catalyzed Homocoupling of gamma-Alkylated tert-Propargylic Alcohols

An unprecedented rhodium-catalyzed homocoupling reaction of gamma-alkylated tert-propargylic alcohols is reported, and 2-alkynylated buta-1,3-diene or 2-alkynylated hexa-1,3,5-triene are generated selectively. Multiple beta-eliminations, including sequential beta-carbon, beta-hydrogen, and beta-oxygen eliminations from the corresponding rhodium intermediates, are assumed to be involved during the reaction process.