Amine-functionalized MCM-41 as an efficient catalyst for the synthesis of sulfur/dinitrogen-fused heterocycles via [3+3] cycloaddition in water

Abstract

The sulfur/dinitrogen-containing heterocycle is an important chemical motif and is found widely in natural products, drug molecules, catalysts and functional materials. Herein, we report efficient, recoverable, amine-functionalized mesoporous materials for the [3+3] cycloaddition of 1,4-dithiane-2,5-diol with azomethine imines in water. A series of desired thiazine heterocyclic compounds was achieved in high yields (82%–98%) in a short time at room temperature. Notably, the best result was observed with 0.05 g of MCM-41–NH₂ that could promote the reaction to 83% yield in 15 min in the gram-scale experiments. Moreover, combined with the good recycling results, the stability of the amine-functionalized MCM-41 and the practicability of the protocol were proved. Finally, a possible mechanism was also discussed.