ABSTRACT 4 H ‐3,1‐Benzoxazines represent important six‐membered heterocyclic compounds in organic chemistry, and the intramolecular cyclization of olefinic amides with various radical species or electrophiles has been established as an efficient strategy for the synthesis of 4 H ‐3,1‐benzoxazines. Recently, increasing efforts have been devoted to developing more efficient and sustainable synthetic approaches toward 4 H ‐3,1‐benzoxazines under various reaction conditions. In this review, we provided an overview of the recent progress for the construction of 4 H ‐3,1‐benzoxazines via annulation of olefinic amides. A series of different substituted 4 H ‐3,1‐benzoxazines were synthesized through cyclization of olefinic amides with different radical species or electrophiles are surveyed herein. We also discussed the substrate scope and mechanistic details of these reactions.
Niu et al. (Wed,) studied this question.