Synthesis of Dihydropyrazoles via Palladium-Catalyzed Cascade Heterocyclization/Carbonylation/Arylation of ,-Unsaturated N-Tosyl Hydrazones

A Pd-catalyzed heterocyclization/carbonylation/arylation cascade reaction between beta,gamma-unsaturated N-Ts hydrazones and commercially available arylboronic acids as coupling partners is described, producing 2-pyrazoline-ketone derivatives in 11-78% yield. A detailed statistical analysis of reactivity patterns of boronic acids provided key information about the limitations of the method, highlighting the challenges of degradation pathways. Our methodology offers a tool for synthesizing diverse 2-pyrazoline-ketone derivatives, expanding the toolbox of accessible N-N-heterocycles.