Lewis base-catalyzed cascade [4 + 2]-annulation reaction of -alkoxy acrylamides and acyl isothiocyanates: facile access to 2-imino-1,3-thiazinone derivatives

• Published in: Organic & biomolecular chemistry Vol. 21; no. 46; pp. 92 - 929
• Main Authors: Wang, Zhaoxue, Tian, Ge, Shi, Yuying, Liu, Wanxing, Xu, Xiangdong, Li, Xiaojing, Wu, Lingang, Xie, Lei
• Format: Journal Article
• Published: 29.11.2023
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/d3ob01440a

A formal [4 + 2]-cycloaddition reaction of N -alkoxy acrylamides and acyl isothiocyanates was developed via a Lewis base-catalyzed cascade aza-nucleophilic addition/thio-Michael addition process under mild conditions. This study provides a facile approach for preparing 2-imino-1,3-thiazinone derivatives in moderate to excellent yields and enriches the field of heterocyclic acrylamide chemistry. The reported method features metal-free reaction conditions, high atom economy, and easy operation. Moreover, the reaction was successfully scaled up and derivatization reactions were successfully performed. A Lewis base-catalyzed cascade aza-nucleophilic addition/thio-Michael addition reaction of N -alkoxy acrylamides with acyl isothiocyanates has been developed to afford various 2-imino-1,3-thiazinone derivatives in 40-97% yields.