Palladium-Catalyzed Double Reductive Cyclization of 2,3-Dinitro-1,4-dialkenylbenzenes. Synthesis of 1<i>H</i>,8<i>H</i>-Pyrrolo[3,2-<i>g</i>]indoles
作者:Nurul H. Ansari、Serge Banini、Matthew M. Cummings、Björn C. G. Söderberg
DOI:10.1021/acs.joc.9b03290
日期:2020.3.20
8H-pyrrolo[3,2-g]indole has been developed. The key and ultimate step is a double palladium-catalyzed, carbon monoxide mediated reductive cyclization of 1,4-dialkenyl-2,3-dinitrobenzenes. The cyclization precursors were prepared by a double Kosugi–Migita–Stille cross coupling of 1,4-dibromo-2,3-dinitrobenzene with an alkenyltin reagent to give symmetrical products. Unsymetrical cyclization precursors were
已开发出一条灵活的路线,可同时生成对称和不对称的 1 H ,8 H -吡咯并 [3,2- g ] 吲哚。关键和最终步骤是双钯催化、一氧化碳介导的 1,4-二烯基-2,3-二硝基苯的还原环化。环化前体是通过 1,4-二溴-2,3-二硝基苯与烯基锡试剂的双重 Kosugi-Migita-Stille 交叉偶联制备的,得到对称产物。使用 4-iodo-2,3-dinitrophenyl trifluoromethanesulfonate 作为起始材料,通过两个连续的交叉偶联制备不对称环化前体。