首次描述了在过苯甲酸叔丁酯叔-丁酯 (TBPB) 存在下，通过酮的α-C(sp3)–H 官能化进行烯酰胺自由基环化的一种新的高效且实际可行的方法。该方法可在不含催化剂、配体或碱的温和条件下，以极好的收率合成得到宽范围的关键和有用苯并噁嗪，并且具有广泛的官能团耐受性。此外，机理研究表明，该转化设计 α-羰基自由基。

A new, efficient, and practical radical cyclization of olefinic amides with ketones through α-C(sp3)–H functionalization in the presence of tert-butyl peroxybenzoate (TBPB) is described for the first time. This protocol assembles a wide range of pivotal and useful benzoxazines in good to excellent yields under mild, catalyst-free, ligand-free, and base-free conditions with wide functional group tolerance. Moreover, the mechanistic study indicates that the α-carbonyl radical is involved in this transformation.