Assembly of Nitrated Isoxazoles via a Multicomponent Cascade Reaction Using Benzoxathiazine-2,2-dioxides as C1 Synthons

A novel multicomponent cascade reaction involving benzoxathiazine-2,2-dioxides, styrenes, and sodium nitrite has been developed. This method provides a facile and practical one-pot route to nitrated isoxazoles under transition-metal-free conditions. Notably, it first utilizes benzoxathiazine-2,2-dioxides as C1 synthons and exhibits excellent regioselectivity. Moreover, the introduced phenolic hydroxyl groups in the products offer promising handles for further structural diversification, enhancing their potential for active drug development.