<scp>Palladium‐Catalyzed</scp> Tandem Carbonylative <scp>Aza‐Wacker‐Type</scp> Cyclization of Nucleophile Tethered Alkene to Access Fused <scp><i>N</i>‐Heterocycles</scp>
Lijun Shi, Mingshan Wen, Fuwei Li
Abstract
Main observation and conclusion Although tandem reactions offer rapid access to structurally complex molecules in one‐pot reaction, the selectivity issue needs to be addressed particularly when incompatible step reactions are involved. Herein, we report the selective synthesis of fused N ‐heterocycles from nucleophile‐tethered alkenylamide and carbon monoxide via palladium (Pd)‐catalyzed tandem carbonylative aza‐Wacker‐type cyclization. The electron‐deficient nature of amide N—H and the intramolecular coordination of Pd with alkene accelerate the aminopalladation and effectively prevent the side oxidative carbonylation of diamine moiety to form urea. It is also found that the reported acyl Pd chloride intermediate may not be involved in this tandem cyclization. This work not only provides an efficient synthetic route to fused 1,4‐diazepanones and 1,4‐diazepanes but also inspires further development of tandem reactions for the diverse synthesis of heterocycles.