Bismuth Meets Olefins: Ethylene Activation and Reversible Alkene Insertion into Bi─N Bonds

Abstract Owing to its fundamental properties as the parent olefin, its outstanding industrial relevance, and the challenges associated with its activation, ethylene remains a benchmark substrate, especially in main group chemistry. Here we report the unprecedented activation of ethylene and related simple α‐olefins by well‐defined cationic bismuth complexes. The polarization of a substrate by a softly Lewis‐acidic central atom and a nucleophilic functional group positioned in a constrained geometry is for the first time exploited in the activation of ethylene and related olefins by compounds of a heavy p‐block element. Mechanistic investigations point toward a coordination‐insertion‐reaction mechanism. The bonding properties of the cationic bismuth species facilitate unprecedented reversible reactivity patterns and unusual characteristics in chemoselectivity.