Synthesis of 2,3-Disubstituted Benzo[<i>b</i>]thiophenes via Palladium-Catalyzed Coupling and Electrophilic Cyclization of Terminal Acetylenes
作者:Dawei Yue、Richard C. Larock
DOI:10.1021/jo011016q
日期:2002.3.1
alkyl-substituted terminal acetylenes undergo this coupling and cyclization to produce excellent yields of benzo[b]thiophenes. (Trimethylsilyl)acetylene also undergoes this coupling/cyclization process with I(2), NBS, and the sulfur and selenium electrophiles to afford the corresponding 2-(trimethylsilyl)benzo[b]thiophenes. However, cyclization of the silyl-containing thioanisole using Br(2) affords
通过在钯催化剂的存在下,将末端乙炔与市售的邻-碘硫代苯甲醚偶联,然后对所得的邻-(1-炔基)硫代苯甲醚衍生物进行亲电环化反应,已以高收率制备了2,3-二取代的苯并[b]噻吩。I(2),Br(2),NBS,pO(2)NC(6)H(4)SCl和PhSeCl已被用作亲电子试剂。芳基,乙烯基和烷基取代的末端乙炔经过这种偶联和环化反应,可产生优异的苯并[b]噻吩收率。(三甲基甲硅烷基)乙炔也与I(2),NBS以及硫和硒亲电试剂进行这种偶联/环化过程,得到相应的2-(三甲基甲硅烷基)苯并[b]噻吩。但是,使用Br(2)对含甲硅烷基的硫代苯甲醚环化,可得到2,3-二溴苯并[b]噻吩。