Alkylacetylenes from Alkynylboron Dihalides and Secondary Alkohols

Significance

Functionalized alkynes are important intermediates in various fields of organic synthesis. This method offers a mild and general alternative for the preparation of secondary alkylacetylenes from the terminal ones and benzylic alcohols. Compared to the conventional alkylation or elimination protocols, often giving products contaminated with allenes, this method has no such drawback due to the milder conditions used. α-Aryl benzylic, propargylic and allylic alcohols are all suitable substrates. Diarylcarbinols can be prepared from ArCHO and ArLi in situ, and used further without isolation to obtain substituted benz­hydrylacetylenes.