Cobalt‐Catalyzed Photo‐Semipinacol Rearrangement of Unactivated Allylic Alcohols

• Published in: Angewandte Chemie International Edition Vol. 63; no. 35; pp. e202407827 - n/a
• Main Authors: Lindner, Henry, Carreira, Erick M.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 26-08-2024
• Edition: International ed. in English
• Subjects: Alcohols; Aromatic compounds; Carbamates (tradename); Cobalt; Esters; Ethers; Halides; Ketones; Nitriles; Photocatalysis; Photochemicals; Radical methods; Synthetic methods; Synthetic Methods; Photocatalysis; Radical methods
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202407827

We report a photochemical method for the semipinacol rearrangement of unactivated allylic alcohols. Aliphatic as well as aromatic groups participate as migrating groups, yielding a variety of α,α‐disubstituted ketones. The reaction proceeds under mild conditions and is compatible with ethers, esters, halides, nitriles, carbamates, and substituted arenes. The operationally simple and fully catalytic conditions prescribe 1 mol % benzothiazinoquinoxaline as organophotocatalyst, 0.5 mol % Co‐salen, and 10 mol % lutidinium triflate and, importantly, display reactivity complementary to procedures employing Brønsted acid. We showcase the utility of the protocol in late‐stage drug diversifications.
A photo‐semipinacol rearrangement of unactivated allylic alcohols is reported. Aliphatic as well as aromatic groups participate as migrating groups, yielding a variety of α,α‐disubstituted ketones. The operationally simple conditions prescribe 1 mol % benzothiazinoquinoxaline as organophotocatalyst, 0.5 mol % Co‐salen, and 10 mol % lutidinium triflate and, importantly, display reactivity complementary to procedures that employ Brønsted acid.