Radhoff Niklas, Studer Armido
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany.
Nat Commun. 2022 Jun 2;13(1):3083. doi: 10.1038/s41467-022-30817-3.
The arylation of carboxylic acid derivatives via Smiles rearrangement has gained great interest in recent years. Both radical and ionic approaches, as well as radical-polar crossover concepts, have been developed. In contrast, a reversed polar-radical crossover approach remains underexplored. Here we report a simple, efficient and scalable method for the preparation of sterically hindered and valuable α-quaternary amides via a polar-radical crossover-enolate oxidation-aryl migration pathway. A variety of easily accessible N-alkyl and N-arylsulfonamides are reacted with disubstituted ketenes to give the corresponding amide enolates, which undergo upon single electron transfer oxidation, a 1,4-aryl migration, desulfonylation, hydrogen atom transfer cascade to provide α-quaternary amides in good to excellent yields. Various mono- and di-substituted heteroatom-containing and polycyclic arenes engage in the aryl migration reaction. Functional group tolerance is excellent and substrates as well as reagents are readily available rendering the method broadly applicable.
近年来，通过斯迈尔斯重排实现羧酸衍生物的芳基化反应备受关注。自由基和离子型方法以及自由基-极性交叉概念均已得到发展。相比之下，极性-自由基反向交叉方法仍未得到充分探索。在此，我们报道了一种简单、高效且可扩展的方法，通过极性-自由基交叉-烯醇盐氧化-芳基迁移途径制备空间位阻较大且有价值的α-季铵酰胺。多种易于获得的N-烷基和N-芳基磺酰胺与二取代烯酮反应生成相应的酰胺烯醇盐，这些烯醇盐经单电子转移氧化、1,4-芳基迁移、脱磺酰化、氢原子转移级联反应，以良好至优异的产率提供α-季铵酰胺。各种单取代和二取代的含杂原子芳烃及多环芳烃均可参与芳基迁移反应。官能团耐受性良好，底物和试剂易于获得，使得该方法具有广泛的适用性。
