Univ. Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, 38000, Grenoble, France.
University of Bern, Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP), Freiestrasse 3, 3012, Bern, Switzerland.
Chemistry. 2023 May 16;29(28):e202300303. doi: 10.1002/chem.202300303. Epub 2023 Apr 4.
Several types of Quantum Dots (QDs) (CdS, CdSe and InP, as well as core-shell QDs such as type I InP-ZnS, quasi type-II CdSe-CdS and inverted type-I CdS-CdSe) were considered for generating α-aminoalkyl free radicals. The feasibility of the oxidation of the N-aryl amines and the generation of the desired radical was evidenced experimentally by quenching of the photoluminescence of the QDs and by testing a vinylation reaction using an alkenylsulfone radical trap. The QDs were tested in a radical [3+3]-annulation reaction giving access to tropane skeletons and that requires the completion of two consecutive catalytic cycles. Several QDs such as CdS core, CdSe core and inverted type I CdS-CdSe core-shell proved to be efficient photocatalysts for this reaction. Interestingly, the addition of a second shorter chain ligand to the QDs appeared to be essential to complete the second catalytic cycle and to obtain the desired bicyclic tropane derivatives. Finally, the scope of the [3+3]-annulation reaction was explored for the best performing QDs and isolated yields that compare well with classical iridium photocatalysis were obtained.
几种类型的量子点（QD）（CdS、CdSe 和 InP，以及核壳 QD，如 I 型 InP-ZnS、准 II 型 CdSe-CdS 和倒置 I 型 CdS-CdSe）被考虑用于生成α-氨基烷基自由基。通过猝灭 QD 的光致发光和通过使用烯基砜自由基捕获剂测试乙烯基化反应，实验证明了 N-芳基胺的氧化和所需自由基的生成的可行性。QD 用于自由基[3+3]环化反应中，可得到托烷骨架，这需要完成两个连续的催化循环。几种 QD，如 CdS 核、CdSe 核和倒置 I 型 CdS-CdSe 核壳，被证明是该反应的有效光催化剂。有趣的是，向 QD 添加第二个较短的链配体似乎对于完成第二个催化循环并获得所需的双环托烷衍生物是必不可少的。最后，探索了最佳性能的 QD 的[3+3]环化反应的范围，并获得了与经典铱光催化相当的分离产率。
