Applications of red light photoredox catalysis in organic synthesis

Abstract

Photoredox catalysis has emerged as an efficient and versatile approach for developing novel synthetic methodologies. Particularly, red light photocatalysis catches more attention due to its intrinsic advantages of low energy,...

Electronic Structures and Photoredox Chemistry of Tungsten(0) Arylisocyanides

“…10 mol % W­(CNDipp) 6 or W­(CNDippPh OMe 3 ) 6 , we found 56% and 33% conversions to product, corresponding to TONs of 5 and 3, respectively (Table , entries 6 and 7). Although modest, these results unambiguously establish W­(CNAr) 6 complexes as rare examples of molecular NIR photoredox catalysts − and dual photocatalysts initiated by both one- and two-photon excitation …”

Orange Light-Driven C(sp2)–C(sp3) Cross-Coupling via Spin-Forbidden Ir(III) Metallaphotoredox Catalysis

“…Para-(3), meta- (7,8), and ortho-substituted (10) aryl bromides are equally tolerated in good to excellent yields. Branched (15), cyclic (17), and heteroatom-containing (16) Katritzky salts are also amenable coupling partners. Drug-like scaffolds such as Nmethyl isoindolinone (8) and mexiletine derivative 18 are similarly competent.…”

“…The increased prominence of photoredox catalysis has facilitated the construction of valuable motifs such as the C­(sp 2 )–C­(sp 3 ) bond. − Ru and Ir photocatalysts (PCs) that absorb UV or blue light (380–450 nm) are capable of generating alkyl radicals from a variety of precursors. − Accordingly, many C­(sp 3 ) radical precursors have been activated by judicious PC selection and metallaphotoredox methods (Scheme A). − While visible light metallaphotoredox catalysis is a powerful new platform in organic synthesis, some recent efforts have sought to develop PCs activatable by comparably lower-energy orange or red light irradiation (590–740 nm). − The advantages of low-energy light include increased bulk solution penetration, biological compatibility, and lessened off-cycle reactivity caused by photoexcitation of cocatalysts and/or substrates. − …”

Shining a Light on the Advances, Challenges and Realisation of Utilising Photoredox Catalysis in Pharmaceutical Development

“…These can include cost (when available on scale), reduced toxicity, stability to N‐ and S‐based functional groups and greater structural diversity offering wider potential application. More energy (shorter wavelength) is usually required for activating organic PRCs due to their highly reductive properties, [46] although recent efforts include development and utilisation of PRCs that are active under red and NIR light [47] …”

“…More energy (shorter wavelength) is usually required for activating organic PRCs due to their highly reductive properties, [46] although recent efforts include development and utilisation of PRCs that are active under red and NIR light. [47] Despite the potential benefits, there are presently few examples in the literature of organic PRCs used for large-scale processes. AstraZeneca recently reported the successful use of an organic PRC for the preparation of a key intermediate to ceralasertib.…”