Electrophilic alkynylation: the dark side of acetylene chemistry

Abstract

In addition to the well-established nucleophilic alkynylation, the use of electrophilic alkynes can expand tremendously the scope of acetylene transfer reactions. The use of metal catalysis has recently led to a rebirth of this research area. Halogenoalkynes, hypervalent alkynyliodoniums, acetylene sulfones and in situ oxidized terminal acetylenes are the most often used reagents for electrophilic alkynylation. Heteroatoms such as N, O, S and P can be now efficiently alkynylated. For C–C bond formation, electrophilic acetylenes can be coupled with different organometallic reagents. Recently, the first breakthrough in direct C–H and CC bond alkynylation has also been reported. Finally, sulfonyl acetylenes are efficient for alkyne transfer on carbon-centered radicals.