Synthetic Applications of 3,4-Bis(trimethylsilyl)thiophene: Unsymmetrically 3,4-Disubstituted Thiophenes and 3,4-Didehydrothiophene<sup>,</sup>
作者:Xin-Shan Ye、Henry N. C. Wong
DOI:10.1021/jo962191n
日期:1997.4.1
modification of 3,4-dibromothiophene; and (c) intermolecular thiazole-alkyne Diels-Alder reaction. 3,4-Bis(trimethylsilyl)thiophene (1a) can function as a versatile building block for the construction of unsymmetrically 3,4-disubstituted thiophenes utilizing its stepwise regiospecific mono-ipso-substitution followed by palladium-catalyzed cross-coupling reactions. In this manner, thiophenes 15, 16, 17a-j
3,4-双(三甲基甲硅烷基)噻吩(1a)通过三种途径合成:(a)1,3-偶极环加成;(b)3,4-二溴噻吩的修饰;(c)分子间噻唑-炔Diels-Alder反应。3,4-双(三甲基甲硅烷基)噻吩(1a)可利用其逐步的区域特异性单-ipso取代,然后进行钯催化的交叉偶联反应,来构建不对称的3,4-二取代的噻吩。以这种方式,制备了噻吩15、16、17a-j,19a,b,20、22a-c,23a,b,24a-d,25a-c和27a-j。噻吩-3,4-二基二聚体28和噻吩-3,4-二基四聚体29也是通过钯催化的有机硼氧烷自偶联反应实现的。苯乙烯基噻吩31,通过经由环硼氧烷26c将C-Si键转化为C-Sn键而形成的化合物进行羰基化偶联和锂化,然后用亲电试剂淬灭,从而也提供不对称的3,4-二取代的噻吩33和36a-c。此外,3,4-双(三甲基甲硅烷基)噻吩(1a)可以用作生成高应变环状枯烯3,4-di