Cobaltkatalysierte Photochemische Semipinakol‐Umlagerung Nichtaktivierter Allylalkohole

Abstract

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.