Photoredox catalysis by [Ru(bpy)3]2+ to trigger transformations of organic molecules. Organic synthesis using visible-light photocatalysis and its 20th century roots

Abstract

Reactions triggered by light constitute a treasure trove of unique synthetic methods that are available to chemists. Photoinduced redox processes using visible light in conjunction with sensitizing dyes offer a great variety of catalytic transformations useful in the realm of organic synthesis. The recent literature amply shows that this preparative toolbox is expanding substantially. This review discusses historical and contemporary work in the area of photoredox catalysis with [Ru(bpy)3]2+. Elegant examples from the most recent literature document the importance of this fast developing area of research. The photoredox chemistry has also emerged as a promising bond-making and bond-breaking tool for chemical biology and materials chemistry. A review with 96 references.

Visible light sensitive photoinitiating systems: Recent progress in cationic and radical photopolymerization reactions under soft conditions

“…The photocatalysts are mainly based on ruthenium or iridium thanks to their intense visible light absorption, long lived excited states and suitable redox potentials. Thus they can work through either an oxidation or a reduction cycle to produce reactive species, e.g., radicals or cations [112][113][114]116,[119][120][121][122][123][124]. Several ruthenium or iridium complexes have been introduced into the photoinitiating systems in the polymer photochemistry field (see Table 2).…”

Amine α-heteroarylation via photoredox catalysis: a homolytic aromatic substitution pathway

“…13 In this context, we have recently demonstrated that photoredox catalysis can be employed to mediate the α-arylation of amines using electron-deficient benzonitrile coupling partners. 14 In this protocol, activation of the amine α-C–H bond is achieved via single-electron oxidation followed by α-deprotonation to generate the critical α-amino radical 1 (Scheme 1).…”

Photocatalytic α‐Oxyamination of Stable Enolates, Silyl Enol Ethers, and 2‐Oxoalkane Phosphonic Esters

“…On the basis of these results, the following mechanism is proposed: After excitation of the photocatalyst by blue . [40] The oxidant is reduced to sulfate and a sulfate radical anion that is capable of accepting an additional electron. [41] Regeneration of the photocatalyst is achieved by oxidizing TEMPO (2) to corresponding oxoammonium ion 2Ј.…”