A novel and efficient strategy for the direct synthesis of benzo[f ]indazoles via copper-catalyzed cascade reaction of sulfonyl hydrazides with 1,3-enynes under mild conditions has been developed. This method achieves the formation of two C−N bonds and one C−C bond in one pot, providing a series of benzo[f ]indazoles in moderate to good yields with good functional group tolerance and remarkable regioselectivity.

A novel copper-catalyzed cascade reaction of arylsulfonylhydrazones derived from ortho-alkynyl arylketones was accomplished. This reaction provides concise access to diversified cinnolines in good yields. The mechanistic investigations have disclosed involvement of the key alkynyl amination, 1,4-aryl migration, desulfonylation, and diazo radical cyclization cascade in the transformation.

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α,β-Unsaturated carbonyl compounds are significant moieties in many biological molecules and have attracted considerable attention in organic synthetic chemistry. A Pd-catalyzed cascade cyclization for the synthesis of (E)-α,β-unsaturated carbonyl compounds with the sequential formation of C−C bonds was developed. This method offers high efficiency, good functional group tolerance, and moderate to excellent yields and generally displays high stereoselectivity.