Engaging Alkenes in Metallaphotoredox: A Triple Catalytic, Radical Sorting Approach to Olefin-Alcohol Cross-Coupling
Qinyan Cai, Iona M. McWhinnie, Nathan W. Dow, Amy Chan, David W. C. MacMillan
Abstract
Metallaphotoredox cross-coupling is a well-established strategy for generating clinically privileged aliphatic scaffolds via single-electron reactivity. Correspondingly, expanding metallaphotoredox to encompass new C( sp 3 )-coupling partners could provide entry to a novel, medicinally relevant chemical space. In particular, alkenes are abundant, bench-stable, and capable of versatile C( sp 3 )-radical reactivity via metal-hydride hydrogen atom transfer (MHAT), although metallaphotoredox methodologies invoking this strategy remain underdeveloped. Importantly, merging MHAT activation with metallaphotoredox could enable the cross-coupling of olefins with feedstock partners such as alcohols, which undergo facile open-shell activation via photocatalysis. Herein, we report the first C( sp 3 )–C( sp 3 ) coupling of MHAT-activated alkenes with alcohols by performing deoxygenative hydroalkylation via triple cocatalysis. Through synergistic Ir photoredox, Mn MHAT, and Ni radical sorting pathways, this branch-selective protocol pairs diverse olefins and methanol or primary alcohols with remarkable functional group tolerance to enable the rapid construction of complex aliphatic frameworks.