Iodine‐Catalyzed, Stereo‐ and Regioselective Synthesis of 4‐Arylidine‐4H‐benzo[d][1,3]oxazines and their Applications for the Synthesis of Quinazoline 3‐Oxides

Abstract 4‐Benzylidene‐2‐aryl‐4 H ‐benzo[ d ][1,3] oxazines have been synthesized with high stereoselectivity and regioselectivities from 2‐alkynylbenzamides in the presence of a catalytic amount of I 2 . In the reaction mechanism, iodine plays a key role in two different aspects as a catalyst, such as to activate the alkyne with the iodinium donor which triggers the cascade, and then as a proper acid source to facilitate catalyst recovery. The benzoxazines have been exploited as potential substrates for the synthesis of quinazoline 3‐oxide derivatives directly in one step.