K₂S₂O₈/TEMPO-Induced Cascade Oxidative Cyclization/1,2-Migration of Electron-Deficient Groups: Strategy for the Construction of 1H-Pyrrol-2(3H)-ones

Abstract

A KSO/TEMPO-induced oxidative cyclization of N-unprotected enaminoesters and enaminones that gave 1 H-pyrrol-2(3 H)-ones in good yields with broad functional group compatibility is reported. This method provides easy access to 1,2-carbon migration of ester or acyl group under transition-metal-free conditions.

The Utility of Oxoammonium Species in Organic Synthesis: Beyond Alcohol Oxidation

“…by Gao and Guan et al in 2018. 222 In 2018, Lancaster and Lin et al reported the electrochemical azidooxygenation of alkenes mediated by a TEMPO-N3 charge-transfer complex. 223 The authors proposed the electrochemically generated TEMPO + forms a charge-transfer complex with azide (TEMPO-N3), which facilitates the generation of an azidyl radical (•N3) after extensive mechanistic studies.…”

Gold-catalyzed reactions using N-propargyl β-enaminones

“…[29][30][31][32][33] Enaminones are gaining increasing interest because of their unique properties and their importance in organic synthesis as versatile building blocks. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] The nucleophilic addition of a variety of functional groups both inter-and intramolecularly toward enaminones utilizing cationic gold (I) and gold (III) complexes have become the most popular in recent years. [49][50][51] This review covers the recent developments in gold-catalyzed reactions using N-propargyl β-enaminones to construct interesting molecules.…”

Construction of the 2-Amino-1,3-selenazole Skeleton via PhICl2/KSeCN-Mediated Selenocyanation/Cyclization

“…Recently, our group realized the synthesis of the biologically interesting SeCN-containing isocoumarins via the PhICl 2 /KSeCN-mediated electrophilic selenocyanation of o -(1-alkynyl)­benzoates . On the contrary, enaminones are also important building blocks that can undergo various β-functionalization/cyclizations, allowing for the construction of a series of heterocyclic skeletons, including 2 H -azirine, − oxazole, − thiazole, , pyridine, and pyrrolone. , Inspired by the enriched convertibility of the selenocyano group combined with our continuous impetus for developing a novel method for β-functionalization of enaminones, we were interested in investigating the reaction between enaminones with PhICl 2 and KSeCN, for the purpose of finding a new way to access the pharmaceutically interesting 1,3-selenazole skeleton (Scheme d).…”