Visible-Light Photoredox Catalysis

Batch to flow deoxygenation using visible light photoredox catalysis

Herein we report a one-pot deoxygenation protocol for primary and secondary alcohols developed via the combination of the Garegg-Samuelsson reaction, visible light-photoredox catalysis, and flow chemistry. This procedure is characterized by mild reaction conditions, easy-to-handle reactants and reagents, excellent functional group tolerance, and good yields.

Switching the activity of a photoredox catalyst through reversible encapsulation and release

Reversible encapsulation of [Ru(bpy)(3)](2+) within a self-assembled hexameric resorcin[4]arene capsule turns off the photocatalytic aerobic oxidation of an aliphatic sulfide. Upon addition of a competitive cationic guest, the Ru(II) catalyst is released into solution where its catalytic activity is restored.

Visible-light-mediated α-arylation of enol acetates using aryl diazonium salts

Visible light mediates efficiently the α-arylation of enol acetates by aryl diazonium salts under mild conditions using [Ru(bpy)(3)]Cl(2) as a photoredox catalyst. The broad scope of the reaction toward various diazonium salts and enol acetates was explored. The application of this reaction in the concise synthesis of 2-substituted indoles was demonstrated.

Visible light photocatalytic synthesis of benzothiophenes

The photocatalytic reaction of o-methylthio-arenediazonium salts with alkynes yields substituted benzothiophenes regioselectively through a radical annulation process. Green light irradiation of eosin Y initiates the photoredox catalysis. The scope of the reaction was investigated by using various substituted diazonium salts and different alkynes.

A visible-light-mediated oxidative C-N bond formation/aromatization cascade: photocatalytic preparation of N-arylindoles

Indoles: A joint effort of light and air We have developed a mild aerobic oxidation protocol using visible light photocatalysis to synthesize structurally diverse N -arylindoles. The procedure employs 4 mol% [Ru(bpz)3](PF6)2, 18W LED light, and is performed open to the atmosphere. Readily prepared o -stryryl anilines are converted to a variety of indoles via a cascade sequence composed of oxidation of anilines, C-N bond formation, and aromatization. A 1,2-carbon shift can be also incorporated into this cascade event to further extend the substrate scope of the method. bpz = 2, 2′-Bipyrazine