Gold(I)-Catalyzed Reaction of 1-(1-Alkynyl)-cyclopropyl Ketones with Vinyldiazo Ketones for Divergent Synthesis of Substituted Furanyl Heterocycles

Gold(I)-catalyzed reactions between 1-(1-alkynyl) cyclopropyl ketones and vinyldiazo ketones to produce substituted [(furan-3-yl)ethyl]-1H-pyrazol-5-yl)methanones are described. In this reaction sequence, we postulate vinyldiazo ketones to undergo a thermal cyclization to produce pyrazole intermediates that attack gold-containing all-carbon 1,4-carbon dipoles to afford the observed products. An atypical N(1)-regioselectivity is also rationalized in this reaction model.

Automated summary

Gold(I)-catalyzed reactions between 1-(1-alkynyl) cyclopropyl ketones and vinyldiazo ketones to produce substituted [(furan-3-yl)ethyl]-1H-pyrazol-5-yl)methanones are described. In this reaction sequence, the vinyldiazo ketones undergo a thermal cyclization to produce pyrazole intermediates that attack gold-containing all-carbon 1,4-carbon dipoles, resulting in the formation of the observed products. The atypical N(1)-regioselectivity in this reaction model is also explained.