Weak Brønsted base-promoted photoredox catalysis for C H alkylation of heteroarenes mediated by triplet excited diaryl ketone

Li, Lifan; Song, Xuyan; Qi, Mei-Fang; Sun, Bing

doi:10.1016/j.tetlet.2022.153846

Cited by 3 publications

(1 citation statement)

References 38 publications

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“…To date, many photochemical protocols have been developed for the Minisci reaction, both with the use of metal complex photocatalysts [ 60 , 77 , 78 , 79 , 80 ] and organic photocatalysts [ 81 , 82 , 83 ]. In some specific cases, the Minisci reaction proceeds without a photocatalyst [ 84 , 85 , 86 , 87 ].…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Photocatalysis as a Potent Tool for Organic Synthesis: Cross-Dehydrogenative C–C Coupling of N-Heterocycles with Ethers Employing TiO2/N-Hydroxyphthalimide System under Visible Light

et al. 2023

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Despite the obvious advantages of heterogeneous photocatalysts (availability, stability, recyclability, the ease of separation from products and safety) their application in organic synthesis faces serious challenges: generally low efficiency and selectivity compared to homogeneous photocatalytic systems. The development of strategies for improving the catalytic properties of semiconductor materials is the key to their introduction into organic synthesis. In the present work, a hybrid photocatalytic system involving both heterogeneous catalyst (TiO2) and homogeneous organocatalyst (N-hydroxyphthalimide, NHPI) was proposed for the cross-dehydrogenative C–C coupling of electron-deficient N-heterocycles with ethers employing t-BuOOH as the terminal oxidant. It should be noted that each of the catalysts is completely ineffective when used separately under visible light in this transformation. The occurrence of visible light absorption upon the interaction of NHPI with the TiO2 surface and the generation of reactive phthalimide-N-oxyl (PINO) radicals upon irradiation with visible light are considered to be the main factors determining the high catalytic efficiency. The proposed method is suitable for the coupling of π-deficient pyridine, quinoline, pyrazine, and quinoxaline heteroarenes with various non-activated ethers.

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