Ruthenium-catalyzed α-carbonyl sulfoxonium ylide annulations with aryl substituted pyrazoles via C-H/N-H bond functionalizations.

An efficient method for the construction of various pyrazolo[5,1-a]isoquinolines has been achieved via Ru(ii)-catalyzed α-carbonyl sulfoxonium ylide annulations with aryl substituted pyrazoles. This oxidant-free transformation occurred through pyrazole-directed C-H activation, Ru-carbene insertion, and acid-promoted carbonyl condensation processes, enabling dual C-C and C-N bond formation. A broad substrate scope with respect to both coupling components worked efficiently with high yields.