Electrochemical oxidative cascade cyclization of olefinic amides and alcohols leading to the synthesis of alkoxylated 4H-3,1-benzoxazines and indolines†
Synthesis technologies can be used directly and selectively to construct two different heterocycles from one substrate. Herein, we introduce a mild and efficient electrochemical oxidative strategy to construct alkoxylated 4H-3,1-benzoxazines and indolines. High atom efficiency and transition metal- and oxidant-free conditions are the striking features of this protocol. In a simple undivided cell, various olefinic amides and alcohols react to generate 40 examples of benzoxazines and indolines. This radical cascade reaction provides a facile method for constructing C–O bonds in one step. Furthermore, most of the compounds exhibit good inhibitory activity on tumour cell lines.