Visible‐Light Photoredox Catalysis in Flow

Abstract

Photoredox catalysis: A variety of organic transformations mediated by visible‐light‐active photoredox catalysts have been conducted in a photochemical flow reactor. The reactor design is very simple and can be easily implemented in any laboratory (see picture). In addition, this reactor afforded a marked increase in the reaction rate compared to those observed in typical batch (round bottom flask) reactors.

Chemical reaction engineering, process design and scale-up issues at the frontier of synthesis: Flow chemistry

“…Examples of batch cyclisation reactions were proposed with much higher yield in continuous mode with respect to batch [90]. In other cases, some synthetic routes have been appealed as too slow in batch mode, therefore abandoned, whereas in continuous mode the applicative possibilities change dramatically.…”

Protecting group-free, selective cross-coupling of alkyltrifluoroborates with borylated aryl bromides via photoredox/nickel dual catalysis

“…This strategy, combined with the ability for orthogonal cross-coupling in the presence of a variety of sp 2 -hybridized boronic acid derivatives, including MIDA boronates, presents an opportunity for greatly expanding the capabilities of this potentially important technology. The ability of the orthogonal cross-couplings to be performed without intermediate purification bodes favorably for application in an automated fashion, and the compatibility of photoredox chemistry with continuous flow reactors has been previously established (32).…”

Design Consideration of Continuous-Flow Photoreactors

“…A mirrored Erlenmeyer flask was positioned above the reactor in order to reflect the incident light back onto the tubing. 68 Several processes, including C-C bond formation, one-pot deoxygenation of primary and secondary alcohols 69 and dehalogenation of alkyl, alkenyl and aryl iodides, 70 have been investigated by having recourse to this device, with satisfactory yields and short residence times (down to 1 min). As an example, aryl iodide 26 was reduced to 27 in 88% yield with a 40-min residence time in the presence of 0.05 mol% of an Ir-based catalyst, with a 120-fold improvement compared to the conversion rate obtained under batch conditions (Figure 1.22).…”