Synthesis of Nitro-Containing Compounds through Multistep Continuous Flow with Heterogeneous Catalysts

Synthesis of β-nitrostyrene derivatives and their following reactions through two-step continuous-flow protocols with heterogeneous catalysts are described. In the first step to provide β-nitrostyrenes from aromatic aldehydes and nitromethane, readily available amino-functionalized silica gel was employed as a catalyst and gave the products continuously for at least 100 h with high selectivity. In the second step, reactions of β-nitrostyrenes, solid bases, immobilized bases, solid acids, and chiral supported metals and nonmetals were used as catalysts, and seven kinds of nitro-containing organic compounds could be effectively synthesized through the two-step continuous-flow systems.