Copper‐Mediated/Catalyzed Oxyalkylation of Alkenes with Alkylnitriles

A copper-promoted oxyalkylation of alkenes with alkylnitriles has been developed. The protocol provides rapid access to phthalides (γ-lactones) or isochromanones (δ-lactones) via the formation of a C(sp(3) )C(sp(3) ) and a C(sp(3) )O bond with the generation of up to two quaternary carbon atoms. Mechanistic studies suggest that this reaction is initiated by the formation of the C(sp(3) )C(sp(3) ) bond rather than the C(sp(3) )O bond. Catalytic conditions were subsequently developed using carboxylic acid as an internal nucleophile.