A base-mediated [2 + 4] annulation of in situ formed azaoxyallyl cations with in situ generated aza-oQMs has been realized. This one-pot cycloaddition process assembled the corresponding 1,4-dihydro-2H-benzo[d][1,3]oxazines in moderate to good yields (up to 99% yield).
![Graphical abstract: Base-mediated [2 + 4] cycloadditions of in situ formed azaoxyallyl cations with N-(2-chloromethyl)aryl amides](http://hg.y866.cn/compound/lib/scimg/usr/1/C8OB02176G.jpg)
