A hydroxyl-assisted, organophotoredox/cobalt dual catalyzed annulation of 2-propynolphenols to form 2-hydroxymethyl-benzo[b]furans was developed by employing 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) as photosensitizer and CoCl₂(PPh₃)₂/5,5′-dimethyl-2,2′-bipyridine as cobalt catalytic precursor. Various substrates and functional groups were tolerated. The practical applications of this reaction were further demonstrated by enlarged gram-scale and various derivations for complex heterocycles. Primary mechanistic studies suggested the involvement of cobalt-hydride mediated hydrogen atom transfer (HAT) process.

中文翻译：

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双钴和光氧化还原催化使 2-丙炔酚的氧化还原中性环化成为可能

通过使用 1,2,3,5-四(咔唑-9-基)-4,6, 开发了羟基辅助的有机光氧化还原/钴双催化环化 2-丙炔酚以形成 2-羟甲基-苯并 [ b ] 呋喃-二氰基苯 (4CzIPN) 作为光敏剂和 CoCl ₂ (PPh ₃ ) ₂ /5,5'-二甲基-2,2'-联吡啶作为钴催化前体。可以容忍各种底物和官能团。该反应的实际应用通过扩大的克级规模和复杂杂环的各种衍生得到进一步证明。主要机理研究表明参与了钴氢化物介导的氢原子转移 (HAT) 过程。