No abstract

A general and expeditious approach for the copper mediated synthesis of multi‐functionalized dihydropyrazoles from N‐sulfonylhydrazones and sulfoxonium ylides has been achieved under aerobic oxidative conditions. The formal [4+1] cycloaddition reaction exhibits many notable features and can be easily scaled up to gram scale.

General comments, general procedure, optimization details, analytic data, and NMR spectra PDF)Accession Codes CCDC 2010044 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing data_

A nickel-promoted cascade annulation reaction for the facile synthesis of 3H-1,2,4-triazol-3-ones from readily available hydrazonoyl chlorides and sodium cyanate has been developed. The transformation occurs through a cascade nickel-promoted intermolecular nucleophilic addition–elimination process, intramolecular nucleophilic addition, and a hydrogen-transfer sequence. The method has been successfully applied for the construction of the core skeleton of the angiotensin II antagonist.

A low cost FeCl 3-mediated cascade annulation of trifluoroacetimidoyl chlorides and hydrazides for the efficient synthesis of 5trifluoromethyl-1,2,4-triazoles has been developed. The transformation proceeds through a cascade base-promoted intermolecular CÀ N bond formation and FeCl 3-mediated intramolecular dehydration sequence under mild conditions. The protocol exhibits many notable features and can be readily scaled up to gram scale.