A Practical, One-Pot Synthesis of Highly Substituted Thiophenes and Benzo[<i>b</i>]thiophenes from Bromoenynes and <i>o</i>-Alkynylbromobenzenes
作者:Verónica Guilarte、Manuel A. Fernández-Rodríguez、Patricia García-García、Elsa Hernando、Roberto Sanz
DOI:10.1021/ol201970m
日期:2011.10.7
An efficient synthesis of thiophenes and benzo[b]thiophenes has been developed from easily available bromoenynes and o-alkynylbromobenzene derivatives. This novel one-pot procedure involves a Pd-catalyzed C–S bond formation using a hydrogen sulfide surrogate followed by a heterocyclization reaction. Moreover, in situ functionalization with selected electrophiles further expands the potential of this
由容易获得的溴代炔和邻炔基溴苯衍生物已开发出噻吩和苯并[ b ]噻吩的有效合成方法。这种新颖的一锅法涉及使用硫化氢替代物进行钯催化的C–S键形成,然后进行杂环化反应。此外,用选定的亲电试剂进行原位官能化进一步扩大了该方法在制备相应的高度取代的硫杂环化合物方面的潜力。
Access to Substituted Thiophenes through Xanthate-Mediated Vinyl C(sp<sup>2</sup>)-Br Bond Cleavage and Heterocyclization of Bromoenynes
Using inexpensive and safe EtOCS2K as a thiol surrogate and tetrabutylphosphonium bromide and H2O as a mixed solvent, the reaction provided a range of substituted thiophenes in moderate to good yields. In addition, 2,3,4,5-tetrasubstituted thiophenes were able to be prepared under mild reaction conditions by electrophilic heterocyclization with NH4I and EtOCS2K in good yields.