benzo[b]furans and 3-methyl-2-substituted benzo[b]thiophenes using low-cost, abundant, and easy-to-use solid calcium carbide instead of flammable and explosive gaseous acetylene as an original alkyne source, o-bromophenyl ethers or o-bromophenyl thioethers as substrates through an intramolecular carbanion-yne cyclization in a 5-exo-dig manner, and subsequent double-bond isomerization is described.
一种使用低成本、丰富且易于使用的固体
碳化钙来简便构建 3-甲基-2-取代苯并[ b ]
呋喃和 3-甲基-2-取代苯并[ b ]
噻吩的简明方法描述了以易燃易爆的气态
乙炔为原始
炔烃源,以邻
溴苯醚或邻
溴苯硫醚为底物,通过5- exo-dig方式进行分子内碳负离子-炔环化,以及随后的双键异构化。两个C-C键的同时形成是通过一步路线实现的。该方法的优点还包括底物范围广、产率高和后处理操作简单。该合成策略也适用于克级。