A Pd-catalyzed heterocyclization/carbonylation cascade reaction encompassing the formation of 3 new bonds, affording dihydropyrazole-esters in moderate to excellent yields and good functional group tolerance is described, comprising a new methodology for direct access to esterified heterocycles using alcohols as readily available feedstock. Optimization was carried out along with a phosphine/base parameterization study, providing important structure-reactivity insights for pyridinebases, mono-and bisphosphines.

Herein, we report the synthesis of 3-carbonyl-trisubstituted furans via Pd-catalyzed oxidative cycloisomerization reactions of 2-alkenyl-1,3-dicarbonyl scaffolds, using molecular oxygen as the sole oxidant to regenerate active palladium catalytic species, featuring good functional tolerance and mild reaction conditions. Deep investigation of intermediates and transition states of the reaction mechanism were conducted via experimental and DFT studies, providing a detailed mechanistical profile. The new developed methodology presents a greener alternative to Wacker-type cycloisomerizations and avoids the use of stoichiometric amounts of oxidants and strong acid additives.

Herein, we report a fully detailed mechanistical study involving an organocatalyzed 1,3-dipolar cycloaddition via a enolate or stabilized vinylogous carbanion intermediates and azide for the synthesis of 1,2,3-triazoles. A detailed...