Redox-Divergent Reactivity of a Gallium(I) Ambiphile toward an Allene, a Diyne, and Ph3PCN2.

Main-group element compounds featuring a low-valent metal center typically undergo oxidative addition reactions with organic substrates, while processes without a change of the oxidation state remain rare. Here, we present a study of the ability of our recently reported gallanediyl 1 to undergo carbometalation reactions with an allene and a diyne. In either case, selective 1,2-syn-addition reactions with retention of the low oxidation state and the singly bonded nature of the gallium center are observed. In contrast, with the diazophosphorus ylide Ph3PCN2 an oxidative cycloaddition reaction takes place and gives rise to the C, Ga, N, P-heterocycle 4. These advances hint toward the utilization of low-valent main-group element compounds in catalytic transformations that are hitherto limited to noble metals.