Tandem versus single C–C bond forming reaction under palladium–copper catalysis: regioselective synthesis of α-pyrones fused with thiophene
作者:Sirisilla Raju、Venkateswara Rao Batchu、Nalivela Kumara Swamy、R. Vasu Dev、Bukkapattanam R. Sreekanth、J. Moses Babu、K. Vyas、P. Rajender Kumar、K. Mukkanti、Pazhanimuthu Annamalai、Manojit Pal
DOI:10.1016/j.tet.2006.07.095
日期:2006.10
α-pyrone fused with thiophene. This includes one-pot and regioselective synthesis of 4,5-disubstituted and 5-substituted thieno[2,3-c]pyran-7-ones, 6,7-disubstituted and 6-substituted thieno[3,2-c]pyran-4-ones. The synthesis of thieno[2,3-c]pyran-7-ones involves palladium mediated cross coupling of 3-iodothiophene-2-carboxylic acid with terminal alkynes in a simple synthetic operation. The coupling–cyclization
我们在本文中报道了用于与噻吩融合的α-吡喃酮的快速构建的高度方便的方案。这包括4,5-二取代和5-取代的噻吩并[2,3 - c ] pyran-7- one ,6,7-二取代和6-取代的噻吩并[3,2- c ] pyran的一锅法和区域选择性合成。-4-ones。噻吩并[2,3 - c ]吡喃-7-的合成涉及钯介导的3-碘噻吩-2-羧酸与末端炔烃的简单合成操作中的交叉偶联。最初在多种溶剂中存在Pd(PPh 3)2 Cl 2和CuI的条件下研究了偶联-环化反应。5-取代的4-炔基噻吩并[2,3- c当在DMF中进行反应时,以高产率分离出] pyran-7-one。类似地,通过钯催化的2-溴噻吩-3-羧酸与末端炔的交叉偶联,合成了6-取代的7-炔基噻吩并[3,2- c ]吡喃-4-酮。在钯催化剂的存在下,串联的C–C键形成反应可以合理地在这种明显的三组分反应中形成偶联产物。该偶联-环化-偶联过