Formation of quinazolin-4(3H)-ones from N-sulfonoketenimines and 2-aminobenzamides

Quinazolin-4(3H)-one structures are highly valued in synthetic chemistry due to their incorporation into diverse natural products and drug molecules. Here, we present a new approach for constructing quinazolin-4(3H)-ones utilizing the reactive N-sulfonoketenimines, generated in situ from terminal alkynes and sulfonyl azides and 2-aminobenzamides in the presence of CuI and Et₃N. The reaction proceeded smoothly in MeCN at room temperature to afford the target compounds in good efficiency and amenable to gram-scale synthesis.