Funk Brian E, Pauze Martin, Lu Yen-Chu, Moser Austin J, Wolf Gemma, West Julian G
Department of Chemistry, Rice University, Houston, TX 77030, USA.
Lead contact.
Cell Rep Phys Sci. 2023 Apr 19;4(4). doi: 10.1016/j.xcrp.2023.101372. Epub 2023 Apr 12.
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 B 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.
环氧开环反应长期以来一直被用于制备在许多化学子领域中都很有价值的醇类产物。虽然已知许多环氧开环反应，但通过离子方式对环氧化物进行氢化开环仍然具有挑战性，因为条件苛刻且存在活性氢化物亲核试剂。最近的进展表明，自由基化学可以在相对温和的条件下实现环氧氢化开环；然而，这些方法总是需要亲氧金属催化剂和敏感试剂。为应对这些挑战，我们报道了一种新的环氧开环氢化方法，该方法利用受生物启发的、地球上储量丰富的维生素B和以硫醇为中心的氢原子转移（HAT）共催化，在可见光照射下生成马氏醇。这个强大的反应体系具有广泛的底物范围，包括许多亲电和亲核还原不稳定的官能团，否则这些官能团易被氢化物亲核试剂还原或裂解，初步的机理实验与自由基过程一致。
