react with alkynoic acids (AAs) to achieve gold‐catalyzed highly selective cascade reactions to furnish novel indole‐fused skeletons. Furthermore, with this powerful gold catalytic system, a library of indole/pyrrole/thiophene/benzene/naphthalene/pyridine‐based nitrogen‐containing heterocyclic compounds (NCHCs) with scaffold diversity and molecular complexity was constructed rapidly using various amine
scope. In addition, this is the first example of the generation of an indole/thiophene/pyrrole/pyridine/naphthalene/benzene-fused N-heterocycle library through gold catalysis in water from readily available materials. Notably, the discovery of antibacterial molecules from this library demonstrates its high quality and potential for the identification of active pharmaceutical ingredients.
Au(I)-Catalyzed Cascade Reaction Involving Formal Double Hydroamination of Alkynes Bearing Tethered Carboxylic Groups: An Easy Access to Fused Dihydrobenzimidazoles and Tetrahydroquinazolines
作者:Nitin T. Patil、Anil Kumar Mutyala、Pediredla G. V. V. Lakshmi、Balakrishna Gajula、Balasubramanian Sridhar、Gurava Reddy Pottireddygari、Tadikamalla Prabhakar Rao
DOI:10.1021/jo1013228
日期:2010.9.3
A process involving gold(I)-catalyzed formal double hydroamination of alkynes, bearing a tethered carboxylic group, for the synthesis of fused dihydrobenzimidazoles and tetrahydroquinazolines has been developed. A series of transition metal catalysts have been screened for this transformation, and a catalyst system consisting of Ph3PAuCl (1 mol %) and AgOTf (1 mol %) was found to be the best. The procedure entails the reaction of easily accessible starting materials such as alkynoic acids and 1,2-diaminobenzenes/2-aminobenzylamines in the presence of the catalyst in 1,2-dichloroethane at 100 degrees C. In the case of alpha-substituted alkynoic acids, the corresponding products were obtained in high diastereoselectivities; the structure of the diastereomers has been unambiguously characterized by NMR techniques. The mechanism of the reaction is discussed, and the origin of the diastereoselectivities is addressed. It was observed that under the microwave irradiation conditions, the reaction time is significantly shortened (0.5 h).
Catalyst-free one-pot cascade cyclization: An efficient synthesis of isoindolobenzoxazinones and isoindoloquinazolinones derivatives
作者:Wenzhong Li、Baibai Wan、Ran Shi、Si Chen、Jiazhu Li、Fangzhen Wang、Hexu Niu、Xin-Ming Xu、Wei-Li Wang
DOI:10.1016/j.tet.2021.132571
日期:2022.1
A practical and efficient catalyst-free cascade cyclization reaction of 2-acylbenzoic acids with various amino alcohols or diamines was developed. This protocol provides a powerful and straightforward method for the one-pot synthesis of diverse isoindolobenzoxazinones, isoindoloquinazolinones and their derivatives. The synthetic strategy evades the use of catalyst, shows a broad substrate scope and