α’‐Selective Selenium‐catalyzed Allylic C−H Amination of Enol Derivatives

A transition metal‐free Se‐catalyzed C−H amination protocol for α’‐amination of enol derivatives has been developed. This reaction can be used to functionalize a wide variety of oxygen‐ and halogen‐substituted alkenes spanning a vast range of nucleophilicities, giving α’‐aminated enol derivatives with high regioselectivity. Amination of E/Z mixtures of alkenes proceeds stereoconvergently to give the (Z)‐enol derivatives exclusively. Mechanistic studies revealed that the relative reactivity and α’‐regioselectivity of these transformations is determined by substantial resonance donation to the heteroatom‐bound carbon in the transition state. These products participate in traditional reactions of enol derivatives, allowing for efficient functionalization of both α‐ and α’‐positions from a single enol derivative with high diastereocontrol. A selenium catalyst allows C−H amination of a wide range of potentially cross‐reactive enol derivatives with unique selectivity for the α’‐position, thereby unlocking the reactive potential of both ketone α‐positions. Stereoconvergent formation of Z enol derivatives from E/Z mixtures eliminates the need for selective enolization methods. Resonance donation from the oxygen in the ene transition state is responsible for the high regioselectivity.