Sulfonylation of 2-haloquinolines with sulfonyl hydrazides in water for accessing 2-sulfonyl quinolines under catalyst-, reductant-, and additive-free conditions

A catalyst-, reductant-, and additive-free sulfonylation of 2-haloquinolines with sulfonyl hydrazides in water was successfully realized. The reactions proceeded efficiently with both wide substrate scope and high functional group compatibility, leading to the corresponding 2-sulfonyl quinolines in synthetically useful yields. In addition, the protocol could be subjected to scale-up synthesis and be applied to the late-stage modification of biologically active complex molecules. Especially noteworthy is that analytically pure product could also be conveniently obtained through simple workup involving filtration and washing with alcohol, without resorting to cumbersome solvent extraction and column chromatography.