Copper-CatalyzedC(sp)-C(sp3) Coupling of Terminal Alkynes with Alkylsilyl Peroxides via a Radical Mechanism

A copper-catalyzed C(sp)-C(sp(3)) coupling reaction between terminal alkynes and alkylsilyl peroxides is reported. In the presence of a copper catalyst and 4-dimethylaminopyridine, the reaction smoothly affords a variety of internal alkynes by coupling alkylsilyl peroxides and terminal alkynes. Mechanistic studies suggest that the reaction proceeds via a radical mechanism, whereby the alkyl radicals are generated from the alkylsilyl peroxides. The present transformation represents a rare example of a radical-mediated C(sp)-C(sp(3)) coupling reaction of terminal alkynes.