Silver(I)-Catalyzed Tandem Sigamatropic Rearrangement/1,3-H Shift/6π Aza-electrocyclization of N-Propargylic Hydrazones: A Mild Synthetic Route to 1,6-Dihydropyridazines.

A highly efficient AgOTf catalyzed [3,3] sigmatropic rearrangement/1,3-H shift/6π aza-electrocyclization cascade reaction of N-propargylic hydrazones has been developed. This method provides a new mild synthetic route to various polysubstituted 1,6-dihydropyridazines including the 3-CF3-substituted ones with high selectivity.

Synthesis of 4-Arylidenepyrazolones by a Gold-Catalyzed Cyclization/Arylidene Group Transfer Cascade of N-Propioloyl Hydrazones.

An efficient gold-catalyzed cyclization/arylidene group transfer cascade reaction of N-propioloyl hydrazones has been developed. This method provides a novel approach for the synthesis of various functionalized 4-arylidenepyrazolones.