Generation and Radical-Radical Cross-Coupling of Alkenyloxy Radical.

Alkene-attached oxygen radicals are rarely used, as highly reactive oxygen radicals are incompatible with the alkene moiety. The direct radical-radical cross-coupling of O radicals is also challenging (limited to N-O bond formation) because of the lack of suitable persistent radical species. This study demonstrated the feasibility of using Breslow intermediate radical (BIR) as a persistent radical to capture unstable π-conjugated O radicals and allow the C-O radical-radical cross-coupling.