Oxidative mono- and di- vinylation of 1-phenylpyrazole: Aqueous Rh(III)- catalyzed cross dehydrogena

Catal. Commun. 2019, 129, 105727

A water-mediated, green strategy for carbon-carbon dehydrogenative coupling between phenylpyrazole and alkene was developed using a Rh(III) catalyst under aerobic and very mild reaction conditions. The reaction offers temperature controlled selectivity for mono and di-vinylation products as well as the chemoselective formation of both the products. Moreover, an excellent functional group tolerance with high yields of vinylated products for symmetric as well as asymmetric di-vinylated products was observed. In contrast to previously published reports, our Rh-catalyst works efficiently at low mol% and in a comparable reaction time. This represents the first account of this reaction using an environmentally benign solvent.