Iron-Catalyzed Cleavage of Allene C=C Double Bond

While the oxidative cleavage of olefins is well established, the radical-mediated, chemo- and regioselective cleavages of allene C(sp)–C(sp ² ) and C(sp ³ )–C(sp ² ) bonds remain unresolved challenges in synthetic chemistry. These challenges primarily stem from the high reactivity of the unique twisted orthogonal π-systems and the regioselectivity issues associated with adjacent C = C double bonds. Herein, we present base metal-catalyzed cleavage of allenic C(sp)–C(sp ² ) double bonds and C(sp ³ )–C(sp ² ) single bonds utilizing air as an oxidant. These transformations, initiated by hydrogen atom abstraction (HAA) from the allenic C(sp²)-H bonds, lead to the formation of a diverse range of remotely functionalized ketones, alkylated heteroaryls, alkylated nitriles, and deuterated products, all with remarkable site selectivity. In this strategy, the α-silyl effect plays a key role in activating allenic C(sp ² )-H bond thus initiating the HAA from allenes and achieving the desired regioselectivity.