Photoredox/nickel dual-catalyzed regioselective alkylation of propargylic carbonates for trisubstituted allenes

Herein, a highly regioselective alkylation of propargylic carbonates for trisubstituted allenes with alkyl 1,4-dihydropyridine derivatives (1,4-DHPs) is developed via a photoredox/nickel dual-catalyzed process, which represents the first direct approach to access alkylated allene products without alkyl organometallic reagents. This method features a broad substrate scope and mild conditions. A hypothetical mechanism with an alkyl radical and an allenyl Ni(iii) species is proposed. Benzylation products were also obtained to be the complement building blocks for the potential synthesis of pharmaceuticals.

Automated summary

A highly regioselective alkylation method for trisubstituted allenes with alkyl 1,4-dihydropyridine derivatives has been developed through a photoredox/nickel dual-catalyzed process, providing alkylated allene products without the need for alkyl organometallic reagents. The method shows a broad substrate scope and mild reaction conditions, with potential applications in pharmaceutical synthesis.