Wang Zhiqiang, Liu Zhenrong, Shao Ting, Li Zheng
College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070, P. R. China.
J Org Chem. 2024 May 17;89(10):7182-7186. doi: 10.1021/acs.joc.4c00573. Epub 2024 May 2.
A concise method for the facile construction of 3-methyl-2-substituted benzo[]furans and 3-methyl-2-substituted benzo[]thiophenes using low-cost, abundant, and easy-to-use solid calcium carbide instead of flammable and explosive gaseous acetylene as an original alkyne source, -bromophenyl ethers or -bromophenyl thioethers as substrates through an intramolecular carbanion-yne cyclization in a 5- manner, and subsequent double-bond isomerization is described. The simultaneous formation of two C-C bonds is realized in a one-step route. The wide substrate scope, high yield, and simple workup manipulations are also merits of this method. The synthetic strategy can also be suitable for the gram scale.
描述了一种简洁的方法，该方法使用低成本、丰富且易于使用的固体碳化钙替代易燃、易爆的气态乙炔作为原始炔烃源，以溴苯醚或溴苯硫醚为底物，通过分子内碳负离子-炔环化反应，以5-方式简便地构建3-甲基-2-取代苯并呋喃和3-甲基-2-取代苯并噻吩，并随后进行双键异构化。该一步路线实现了两个C-C键的同时形成。底物范围广、产率高以及后处理操作简单也是该方法的优点。该合成策略也适用于克级规模。
