Photoredox-Catalyzed Round-Trip C-H Alkylation of Alcohols

The photoredox-catalyzed C-H alkylation of alcohols was intricated with a round-trip radical cascade leading to a remarkable skeletal remodeling of the alcohol substrates. The reaction conditions involving the use of a carbon dioxide atmosphere, proved essential for broadening the substrate scope and achieving high levels of structural diversification. Mechanistic investigations revealed that the in-situ generation of hydrogen carbonate salts plays a pivotal role in orchestrating the radical cascade, facilitating key steps in the transformation. This work highlights the strategic value of CO₂ as a transient additive to modulate reaction pathways in photoredox catalysis and unlock otherwise elusive reactivity.