Vitamin B12 and hydrogen atom transfer cooperative catalysis as a hydride nucleophile mimic in epoxide ring opening

Epoxide ring-opening reactions have long been utilized to furnish alcohol products that are valuable in many subfields of chemistry. While many epoxide-opening reactions are known, the hydrogenative opening of epoxides via ionic means remains challenging because of harsh conditions and reactive hydride nucleophiles. Recent progress has shown that radical chemistry can achieve hydrogenative epoxide ring opening under relatively mild conditions; however, these methods invariably require oxophilic metal catalysts and sensitive reagents. In response to these challenges, we report a new approach to epoxide ring-opening hydrogenation using bio-inspired Earth-abundant vitamin B12 and thiol-centric hydrogen atom transfer (HAT) co-catalysis to produce Markovnikov alcohols under visible light irradiation. This powerful reaction system exhibits a broad substrate scope, including a number of electrophilic and reductively labile functionalities that would otherwise be susceptible to reduction or cleavage by hydride nucleophiles, and preliminary mechanistic experiments are consistent with a radical process. [Display omitted] •VB12 and thiol HAT co-catalysis enables hydrogenative epoxide ring opening•VB12 and TRIP thiol combine for an Earth-abundant co-catalytic system•Exceptionally mild conditions indicated by broad substrate scope•Mechanistic inquiries suggest a radical process with MeOH-driven thiol regeneration Here, Funk et al. develop a mild synthetic method for hydrogenative epoxide ring opening. The co-catalytic system uses Earth-abundant vitamin B12 and TRIP thiol to efficiently produce Markovnikov alcohols with good yield and broad functional group tolerance.