Photocatalytic aerobic α-thiolation/annulation of carbonyls with mercaptobenzimidazoles

Abstract

A concise aerobic photocatalysis using a blue LED combined with a Lewis acid has been developed to enable α-thiolation/annulation of carbonyls.

Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis

“…Thiyl radical addition across an intermediate aluminum enolate provides access to thiazolidine-containing products ( Scheme 220 ). 598 This reaction utilized molecular oxygen as a terminal oxidant as well as a stoichiometric LA additive to activate the carbonyl substrate to enolate formation. Optimal conditions used RB as a photocatalyst, AlCl 3 as the LA, and MeCN as the solvent under an atmosphere of O 2 with blue-light irradiation.…”

Visible‐Light Cercosporin Catalyzed Sulfenylation of Electron‐Rich Compounds with Thiols under Transition‐Metal‐Free Conditions

“…Recently Huang and group has developed method which describes the α-aryl thiolation via organophotoredox catalysis of ketones. [34] To extend our studies in synthesizing organosulfur compounds, more efficient and greener methods are required to access and as a continuation of this, our effort is in the development of a visible-light promoted sulfenylation of indoles, active methylene compounds and aromatic electron rich compounds with thiols catalyzed by cercosporin as photocatalyst at room temperature. Cercosporin, a naturally occurring perylenequinoid pigment has gained importance owing to its excellent property of strong light absorption to convert itself to an excited state and also because of its ability to generate active oxygen species.…”

“…Lei and Zhu reported oxidative coupling from 1,3‐diketones/cyclic ketones and β‐dicarbonyl thioethers/α‐thio‐β‐dicarbonyl compounds to generate C−S bond. Recently Huang and group has developed method which describes the α‐aryl thiolation via organophotoredox catalysis of ketones . To extend our studies in synthesizing organosulfur compounds, more efficient and greener methods are required to access and as a continuation of this, our effort is in the development of a visible‐light promoted sulfenylation of indoles, active methylene compounds and aromatic electron rich compounds with thiols catalyzed by cercosporin as photocatalyst at room temperature.…”

Visible‐Light‐Triggered Quantitative Oxidation of 9,10‐Dihydroanthracene to Anthraquinone by O2 under Mild Conditions

“…[33][34][35] In particular,t he selectiveo xidation of organic compoundsb ydioxygen (O 2 )o ra ir under visible light is believed to be user-and environmentally friendly,and thus, of great academic and practical significance. [36,37] Herein, we report an atom-efficient and ecofriendly photo-oxidation protocol for the synthesis of AQ from DHA withouta ny extra catalysts or additives under ambient temperature and pressure, which can fully meet the requirements ofg reen chemistry principles. This protocol can achieve quantitative conversion of DHA to AQ (100 %y ield) under 10 hv isible-light irradiation and ap ure O 2 atmosphere.…”

“…In recent years, light‐triggered chemical reactions have emerged as powerful synthesis techniques for the production of fine chemicals under mild reaction conditions . In particular, the selective oxidation of organic compounds by dioxygen (O 2 ) or air under visible light is believed to be user‐ and environmentally friendly, and thus, of great academic and practical significance . Herein, we report an atom‐efficient and ecofriendly photo‐oxidation protocol for the synthesis of AQ from DHA without any extra catalysts or additives under ambient temperature and pressure, which can fully meet the requirements of green chemistry principles.…”