Asymmetric Conjugate Addition of Organoboron Reagents to Common Enones Using Copper Catalysts

Copper complexes of phosphoramidites efficiently catalyzed asymmetric addition of arylboron reagents to acyclic enones. Importantly, rare 1,4-insertion of arylcopper(I) was identified which led directly to O-bound copper enolates. The new mechanism is fundamentally different from classical oxidative addition/reductive elimination of organocopper(I) on enones.