Visible-Light-Promoted Reduction of Epoxides, Hydroxysulfonates and Halohydrines with Alkyltitanium Alkoxides

Alkyltitanium alkoxides generally serve as nucleophiles in the reactions with carbonyl compounds and cross-coupling. Their application as reductants is known but remains underdeveloped. Here, we report that irradiation with visible light makes these organometallic compounds efficient reducing agents for the dehalogenation of 1,2- and 1,3-haloalcohols. This was utilized for the reduction of epoxides and hydroxysulphonates, which started with the in situ formation of haloalkoxies and followed by the photochemical dehalogenation step. Ester, amide, alkyne, sulphone, and remote bromide groups were stable under the reaction conditions.