Cascade cyclization of glycine derivatives with β-ketoesters for polysubstituted 1,4-dihydropyridines by visible light photoredox catalysis
2020
Zhu, Xiao | Zhu, Zhi-Qiang | Guo, Dong | Liu, Shan | Ji, Jiu-Jian | Tang, Juan | Yuan, En | Xie, Zong-Bo | Le, Zhang-Gao
Visible light photocatalytic cascade cyclization reaction between glycine derivatives and β-ketoesters using Ir (ppy)₃ as a catalyst and dicumyl peroxide (DCP) as an oxidant was described. A series of N-aryl glycine esters proceeded the cyclization smoothly with β-ketoesters at room temperature, affording the desired 1,4-dihydropyridines (1,4-DHPs) in satisfactory yields. A possible mechanism for the cascade cyclization reaction by visible light photoredox catalysis was also proposed. This protocol not only provides an efficient and convenient approach to synthetize various 1,4-dihydropyridines, but also has potential utilities for the construction of bioactive molecules.
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