The transient carbonation of polyols under a CO2 atmosphere enables their C−H monoalkylation by photoredox catalysis. This reactivity results from an unprecedented C−H activation through intramolecular hydrogen bonding.
A system for in situ regeneration of SmI2 from SmI3 is described which allows the annulation of ketones to γ-lactones, the deoxygenation of oxiranes to olefins and radical π-cyclization to be conducted with 10 mole % SmI2.