Synthesis of Substituted Pyrazoles via Tandem Cross-Coupling/Electrocyclization of Enol Triflates and Diazoacetates

The synthesis of 3,4,5-trisubstituted pyrazoles via a tandem catalytic cross-coupling/electrocydization of enol triflates and diazoacetates is presented. The initial scope of this methodology is demonstrated on a range of differentially substituted acyclic and cyclic enol triflates as well as an elaborated set of diazoacetates to provide the corresponding pyrazoles with a high degree of structural complexity.