Copper-Catalyzed Regio- and Stereoselective 1,1-Dicarbofunctionalization of Terminal Alkynes

The copper-catalyzed highly regio- and stereoselective 1,1-dicarbofunctionalization of terminal alkynes is realized for the first time. Using a removable, bidentate 8-aminoquinoline auxiliary, the three-component, selective 1,1-arylalkylation of alkynes with α-haloacetamides and organoboronic acids by the addition of both alkyl and aryl groups to the terminal carbon of alkynes was achieved. Mechanistic investigations suggest that the reaction likely proceeds via the copper-catalyzed cross-coupling of terminal alkynes with α-haloamides, rearrangement, transmetalation, syn-carbocupration, and protonolysis.