4,4'-二烷基-4-乙炔基联环己烷(1)和它的偶联衍生物1,4-双((4,4'-二烷基-联环己)-4-基)丁二炔(2)、1,4-双(2-((4,4'-二烷基-联环己)-4-基)乙炔基)芳烃(3)是具有某种特性的重要液晶化合物.文章介绍了以4,4'-二烷基联环己基-4-甲腈(4)为起始原料的化合物的合成.首先,化合物(4)与甲基锂发生加成反应,水解后制得关键中间体甲基酮化合物(5),接着甲基酮化合物(5)与格氏试剂在特定的条件下反应,高收率地制得炔类化合物(1),关于本反应可能的机理文中也进行了阐述.化合物(1)通过氧化自偶联制得化合物(2).化合物(1)与二卤代芳烃在Pd(0)催化系统下发生偶联制得化合物3,这些化合物的制备具有短的合成步骤和高的反应收率,是高效的合成方法;其中化合物(1)的制备方法从未见诸于以前的任何文献报道.
4,4'-dialkyl-4-ethynylbicyclohexyl (1) and their coupled derivatives 1,4-bis ( ( 4,4'-dialkyl-bicyclohex)-4-yl) butadiyne (2), 1,4-bis ( 2-( ( 4,4'-dialkyl-bicyclohex)-4 yl ) ethynyl )arene(3) are very important liquid crystal compounds with some special characters. In this paper, the preparations of these compounds were developed in which 4,4'-dialkylbicyclohexyl-4-carbonitrile(4) is used as the starting material. Firstly, key intermediate 4-aceto-4,4'-dial-kyl-bicyclohexyl (5) was synthesized in good yield through the addition of methyl lithium to compound 4 followed by hydrolyzation, Then, the compound 1 was prepared in excellent yield through the reaction of compound 5 with Grignard reagent whose presumed mechanism was proposed. Acetylene compound 2 was synthesized through the oxidative self-coupling of compound 1, and the preparation of acetylene compound 3 was advanced through the coupling of compound 1 with aryldibromide in the Pd(0) catalyst system. These preparations have high yields and short procedure which are high efficient synthesis methods, and the preparation method of compound 1 is never reported in any literatures heretofore.
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