Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

Autor: Wei-Hsin Hsu, Susanne Reischauer, Peter H. Seeberger, Bartholomäus Pieber, Dario Cambié
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Beilstein Journal of Organic Chemistry, Vol 18, Iss 1, Pp 1123-1130 (2022)
Druh dokumentu: article
ISSN: 1860-5397
DOI: 10.3762/bjoc.18.115
Popis: Metallaphotoredox catalysis is a powerful and versatile synthetic platform that enables cross-couplings under mild conditions without the need for noble metals. Its growing adoption in drug discovery has translated into an increased interest in sustainable and scalable reaction conditions. Here, we report a continuous-flow approach to metallaphotoredox catalysis using a heterogeneous catalyst that combines the function of a photo- and a nickel catalyst in a single material. The catalyst is embedded in a packed-bed reactor to combine reaction and (catalyst) separation in one step. The use of a packed bed simplifies the translation of optimized batch reaction conditions to continuous flow, as the only components present in the reaction mixture are the substrate and a base. The metallaphotoredox cross-coupling of sulfinates with aryl halides was used as a model system. The catalyst was shown to be stable, with a very low decrease of the yield (≈1% per day) during a continuous experiment over seven days, and to be effective for C–O arylations when carboxylic acids are used as nucleophile instead of sulfinates.
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