An Asymmetric Dehydrogenative Diels–Alder Reaction for the Synthesis of Chiral Tetrahydrocarbazole Derivatives
作者:Xiang Wu、Hai-Jie Zhu、Shi-Bao Zhao、Shu-Sen Chen、Yun-Fei Luo、You-Gui Li
DOI:10.1021/acs.orglett.7b03251
日期:2018.1.5
An asymmetric dehydrogenative Diels–Alder reaction of 2-methyl-3-phenylmethylindoles and α,β-unsaturated aldehydes has been established. The successful in situ generation of the indole ortho-quinodimethane intermediate and the iminium activation of enals are the keys to success, providing various tetrahydrocarbazole derivatives with up to >99% ee.
Efficient copper-catalyzed synthesis of C3-alkylated indoles from indoles and alcohols
作者:Ngoc-Khanh Nguyen、Duong Ha Nam、Ban Van Phuc、Van Ha Nguyen、Quang Thang Trịnh、Tran Quang Hung、Tuan Thanh Dang
DOI:10.1016/j.mcat.2021.111462
日期:2021.4
A highly efficient copper(II) catalyst system for alkylation of indoles with alcohols via hydrogen borrowing method has been developed to afford C3-alkylated indoles in good to excellent yields. Cu(OAc)2 in the combination with dppm ligand has been found to be the most suitable catalyst system for this alkylation reaction.
Cobalt-catalysed CH-alkylation of indoles with alcohols by borrowing hydrogen methodology
作者:Bei Zhou、Zhuang Ma、Asma M. Alenad、Carsten Kreyenschulte、Stephan Bartling、Matthias Beller、Rajenahally V. Jagadeesh
DOI:10.1039/d2gc00469k
日期:——
interesting class of heterocyclic compounds widely used in organic synthesis and medicinal chemistry. Key for this synthesis is the use of specific cobalt-nanoparticles supported on N-doped carbon, which were conveniently prepared by the pyrolysis of a templated material generated in situ by mixing cobalt-nitrate, zinc-nitrate, 2,6-diaminopyridine, and colloidal silica, and subsequent removal of silica
报道了吲哚与醇的一般多相钴催化 CH-烷基化。利用这种直接的借氢方法,一系列取代和官能化的吲哚很容易与包括甲醇在内的苄醇、杂环醇和脂肪醇偶联,以制备 >65 个取代的吲哚,产率从良好到优异。所得产物代表了广泛用于有机合成和药物化学的一类有趣的杂环化合物。该合成的关键是使用负载在 N 掺杂碳上的特定钴纳米颗粒,这些纳米颗粒是通过混合硝酸钴、硝酸锌、2,6-二氨基吡啶和胶体二氧化硅,然后除去二氧化硅。
An efficient route to 2,3-disubstituted indoles via reductive alkylation using H2 as reductant
An efficient route to 2,3-disubstituted indoles was developed via reductive alkylation of 2-substitutedindoles using hydrogen as a clean and atom economic reductant under ambient pressure.
98% ee using a strong Brønsted acid as the activator. This methodology was applied in the facile synthesis of biologically active products containing a chiral indoline skeleton. The mechanism of Pd-catalyzed asymmetric hydrogenation was investigated as well. Isotope-labeling reactions and ESI-HRMS proved that an iminium salt formed by protonation of the C═C bond of indoles was the significant intermediate