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

• Published in: Advanced synthesis & catalysis 2012-08, Vol.354 (11-12), p.2218-2228
• Main Authors: Lee, Wen-Chun, Shen, Ho-Chuan, Hu, Wan-Ping, Lo, Wei-Sheng, Murali, Chebrolu, Vandavasi, Jaya Kishore, Wang, Jeh-Jeng
• Format: Article
• Language: English
• Subjects: 6-exo-dig cyclization; Catalysis; Catalysts: preparations and properties; Chemistry; Exact sciences and technology; General and physical chemistry; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Heterocyclic compounds with several n hetero atoms in the same ring, in separated rings or in fused rings; iodine; Kinetics and mechanisms; Organic chemistry; Preparations and properties; quinazoline 3-oxides; Reactivity and mechanisms; regioselectivity; stereoselectivity; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1615-4150; 1615-4169
• DOI: 10.1002/adsc.201200018

4‐Benzylidene‐2‐aryl‐4H‐benzo[d][1,3] oxazines have been synthesized with high stereoselectivity and regioselectivities from 2‐alkynylbenzamides in the presence of a catalytic amount of I2. 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.