Pyrazole synthesis via a cascade Sonogashira coupling/cyclization of N-propargyl sulfonylhydrazones.

An efficient approach for the preparation of pyrazoles via a Pd(ii)/Cu(i)-catalyzed Sonogashira coupling/cyclization of N-propargyl sulfonylhydrazones has been established. In this study, we firstly report the strategic use of a Sonogashira reaction to construct pyrazole rings in a one step operation. With a broad range of functional group tolerance, bioactive 3-CF3 pyrazoles can also be synthesized easily through this domino coupling/cyclization sequence.

Highly Regio- and Stereoselective Heterogeneous Hydrosilylation of Terminal Alkynes over Cobalt-Metalated Porous Organic Polymer.

A cobalt/POL-PPh3 catalyzed ( E)-selective hydrosilylation of alkynes with PhSiH3 has been developed for the synthesis of ( E)-ß-vinylsilanes with high regio- and stereoselectivity and wide functional group tolerance. It is the first report of using porous organic polymer as a recyclable regio- and stereoselective and efficient ligand in hydrosilylation reactions in which the polymer could be recycled numerous times in a continuous flow system without loss of activity and selectivity. The earth-abundant base-metal catalyst, coordinated by heterogeneous recyclable ligand, shows promise for industrial application.