Substituent-Controllable Cascade Regioselective Annulation of β-Enaminones with N-Sulfonyl Triazoles for Modular Access to Imidazoles and Pyrroles

Abstract

A controllable synthesis of trisubstituted imidazoles and pyrroles has been developed through rhodium(II)-catalyzed regioselective annulation of N-sulfonyl-1,2,3-trizaoles with β-enaminones. The imidazole ring was formed through a 1,1-insertion of the N-H bond to α-imino rhodium carbene, followed by a subsequent intramolecular 1,4-conjugate addition. This occurred when the α-carbon atom of the amino group was bearing a methyl group. Additionally, the pyrrole ring was constructed by utilizing a phenyl substituent and undergoing intramolecular nucleophilic addition. The mild conditions, good tolerance towards functional groups, gram-scale synthesis capability, and ability to undergo valuable transformations of the products qualify this unique protocol as an efficient tool for the synthesis of N-heterocycles.

Stereochemical and Computational NMR Survey of 1,2,3-Triazoles: in Search of the Original Tauto-Conformers

“…The derivatives of azoles, in particular, 1,2,3-triazoles hold a special place in heterocyclic chemistry and find extensive applications in diverse fields of agriculture, materials science, chemical biology, and medicinal chemistry. Readily available 1,2,3-triazoles, with a wide range of various activities, have long been used as high-energy materials, ionic liquids, medicinal products, radiosensitizers, universal bases in peptide nucleic acids, plasticizers, dyes, plant growth regulators, pesticides and herbicides, synthons for fine organic synthesis, and precursors for nanocomposites. − 1,2,3-Triazole derivatives are successfully employed to create numerous drug scaffolds exhibiting anti-HIV, anticancer, antiviral, antibacterial, anti-inflammatory, antiproliferative, aticholinesterase, antioxidant, antifungal activity, etc. ,− ,,,− ,− The therapeutic effects of many compounds containing a 1,2,3-triazole moiety are also well-known.…”