Photocatalytic Vicinal Aminopyridylation of Methyl Ketones by a Double Umpolung Strategy
作者:Honggu Im、Wonjun Choi、Sungwoo Hong
DOI:10.1002/anie.202008435
日期:2020.9.28
umpolung strategy for the vicinal aminopyridylation of ketones was developed using pyridinium N−N ylides. The inversion of the polarity of the pyridinium N−N ylides by single‐electron oxidation successfully enables radical‐mediated 1,3‐dipolar cycloadditions with enolsilanes formed in situ from ketones, followed by homolytic cleavage of the N−N bond. Intriguingly, the nucleophilic amino and electrophilic
使用吡啶鎓N-N烷基化物开发了光催化的双邻位酮酮酮联氨化策略。通过单电子氧化使吡啶鎓N-N基团的极性反转成功地实现了自由基介导的1,3-偶极环加成反应,与由酮原位形成的烯醇硅烷相继发生,随后均化裂解了N-N键。有趣的是,可将ylides中的亲核氨基和亲电吡啶基分别安装在亲核α位置和亲电羰基碳上,这通常是由于其固有的极性驱动反应性而无法实现的。该方法适用范围广,并且通过复杂的生物相关分子的后期功能化进一步证明了该方法的实用性。而且,该策略可以成功地应用于酰胺。