Ugi Four-Component Reaction Based on the in situ Capture of Amines and Subsequent Modification Tandem Cyclization Reaction: "One-Pot" Synthesis of Six- and Seven-Membered Heterocycles

The tandem reaction strategy of Ugi four-component reaction and its subsequent modification reaction based on in situ capture of amines to prepare three types of six- and seven-membered nitrogen-heterocycles are reported. According to this strategy, amines were synthesized in situ and immediately worked as the substrate for the Ugi four-component reaction reaction and subsequent modification tandem reaction. Starting from cheap and easily available nitro compounds, the application scope of substrates has been expanded and the problems of amines of easy oxidation, poor stability and versatility have been solved. Furthermore, due to the atom economy and versatility, the tandem reaction strategy has become a new approach for the synthesis of nitrogen-hete- rocycles. In addition, based on a series of conditional control experiments, a plausible mechanism for the reaction is proposed.