Photo-induced nickel-mediated cross-electrophile coupling for alkylated allenes via electron donor–acceptor complexes

Abstract

Herein, a highly regioselective alkylation of propargylic carbonates for trisubstituted allenes with alkyl N-hydroxyphthalimide (NHP) esters was developed via a nickel-mediated radical cross-electrophile coupling process. Electron donor–acceptor (EDA) complex photoactivation strategies have emerged as a versatile way for alkyl radicals. This method features mild conditions and a broad substrate scope and the involvement of primary alkyl radicals represents the first direct approach for primary alkylated allenes. Preliminary mechanistic studies indicated that this transformation proceeded through a radical–radical coupling process.