Cobalt-catalyzed modular assembly toward multi-functionalized furan derivatives

Abstract

A cobalt-catalyzed modular [3+2] assembling of unsaturated hydrocarbons and β-dicarbonyls is reported. This protocol features mild reaction conditions and a broad substrate scope, providing facile entries toward diverse multi-functionalized dihydrofuran...

Electrocatalytic [3 + 2] Annulation for the Synthesis of Polysubstituted Furans

“…On the basis of these mechanistic probe experiments and previously relevant literature, ,, we propose our speculation on the [3 + 2] annulation process (Figure , D). Anodic oxidation of Fc produced Fc + species, which with the assistance of NaOAc oxidized the β-keto compound to carbon-centered radical 61 and regenerated the Fc catalyst.…”

“…In addition, the You and Roy group also made their contributions in this area using a gold or nickel catalyst . More recently, the group of Ye described a Co­(salen) complex-mediated [3 + 2] assembly to prepare multifunctionalized furan derivatives by employing stoichiometric NFSI as both the oxidant and the HAT reagent . However, these literature precedents still suffer from certain limitations such as the requirement of noble transition metals, excess strong oxidants, harsh conditions, and narrow substrate scope.…”

Synthesis of Polysubstituted Furans: An Update Since 2019

“…Emphasizing on cobalt-catalyzed reactions, [75,76] Ye et al in 2022 reported a multi-functionalized dihydrofuran and furan derivatives 111 from unsaturated hydrocarbons 105 and β-dicarbonyls 106 by cobalt-catalyzed [3 + 2] cycloaddition reactions in good to moderate yields. [77] Mechanistically, single-electron transfer between Co(salen) and N-fluorobenzenesulfonimide produces an organometallic cobalt fluoride as well as a nitrogen-center radical which readily abstracts a hydrogen atom from β-dicarbonyl to generate a radical intermediate 107. The carbocation species 109 is formed by the subsequent radical addition across an alkene 108 followed by another single-electron oxidation.…”

Electrochemically enabled (3+2) cycloaddition of unbiased alkenes and β-dicarbonyls

“…Despite high yields for biased alkenes, coupling of unbiased alkene and b-ketoester delivers the desired products in low yields. 38 Internal alkene cyclooctene also underwent the reaction efficiently to provide the corresponding dihydrofuran This journal is © The Royal Society of Chemistry 2024 4wa in 54% yield as a diastereomeric mixture (anti : syn = 2 : 1). The structure of the syn isomer was confirmed by single crystal XRD studies (CCDC 2326943 †).…”