Anti-Markovnikov hydro- and deuterochlorination of unsaturated hydrocarbons using iron photocatalysis

Hydrochlorination of unsaturated hydrocarbons is a fundamental reaction scheme in organic synthesis, with the traditional acid-mediated approaches proceeding in Markovnikov selectivity and direct access to anti-Markovnikov hydrochlorination products being a longstanding pursuit. Previous efforts were restricted to multistep syntheses, stoichiometric chlorine and hydride sources, and/or highly oxidative photocatalysis, resulting in limited scope, and low regioselectivity in some cases. Thus, the development of redox-neutral hydrochlorination with high anti-Markovnikov regioselectivity compatible with both alkenes and alkynes remains important. Here we report a photocatalytic anti-Markovnikov hydro- and deuterochlorination of unsaturated hydrocarbons enabling access to diverse alkyl and alkenyl chlorides regio- and stereo-selectively. Broad scope (125 examples), mild conditions and regio- and isotopo-divergent syntheses are demonstrated. Critical to success is leveraging ligand-to-metal charge transfer (LMCT) photoreactivity of earth-abundant iron and hydrogen atom transfer (HAT) reactivity of redox-active thiol. This cooperative system offers a powerful strategy for anti-Markovnikov hydrofunctionalization of unsaturated hydrocarbons.