Synthesis of 2,3-Dihydro-1H-azepine and 1H-Azepin-2(3H)-one Derivatives From Intramolecular Condensation between Stable Tertiary Enamides and Aldehydes
Wenju Zhu, Liang Zhao and Mei-Xiang Wang*
*MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China, Email: wangmxmail.tsinghua.edu.cn
W. Zhu, L. Zhao, M.-X. Wang, J. Org. Chem., 2015, 80, 12047-12057.
see article for more reactions
Under very mild conditions employing BBr3 as a Lewis acid catalyst and P2O5 as an additive, tertiary enamides that contain a formyl group underwent highly efficient and scalable intramolecular cyclic condensation to afford diverse 2,3-dihydro-1H-azepine and 1H-azepin-2(3H)-one derivatives in very good yields.
see article for more examples