Donor–Acceptor Bicyclopropyls as 1,6-Zwitterionic Intermediates: Synthesis and Reactions with 4-Phenyl-1,2,4-triazoline-3,5-dione and Terminal Acetylenes
作者:Konstantin V. Potapov、Dmitry A. Denisov、Valeriia V. Glushkova、Roman A. Novikov、Yury V. Tomilov
DOI:10.1021/acs.joc.0c02293
日期:2020.12.4
the presence of Lewis acids was used as a synthetic equivalent of 1,6-zwitterions. Opening of both cyclopropane rings in 2′-aryl-1,1′-bicyclopropyl-2,2-dicarboxylates (D–A bicyclopropyl, ABCDs) in the presence of GaI3 + Bu4N+GaI4– results in 5-iodo-5-arylpent-2-enylmalonates as products of HI formal 1,6-addition to the bicyclopropyl system. The use of GaCl3 or GaBr3 as a Lewis acid and terminal aryl
通过在路易斯酸存在下结合供体基团和受体基团而活化的双环丙基体系被用作1,6-两性离子的合成等价物。在存在GaI 3 + Bu 4 N + GaI 4的情况下,在2'-芳基-1,1'-双环丙基-2,2-二羧酸酯(DA双环丙基,ABCD)中打开两个环丙烷环–产生5-碘-5-芳基戊二烯基丙二酸酯作为双环丙基系统中HI正式1,6-加成的产物。使用GaCl 3或GaBr 3作为路易斯酸,如末端的芳基或烷基乙炔作为1,6-两性离子拦截剂,可使烷基取代基生长,得到相应的无环7-氯(溴)-庚-2,6-二烯基丙二酸酯。Yb(OTf)3催化ABCD与4-苯基-1,2,4-三唑啉-3,5-二酮(PTAD)的反应也导致两个环丙烷环的打开。反应产物是四氢哒嗪衍生物-(7,9-二氧代-1,6,8-三氮杂双环[4.3.0]非-3-烯-2-基甲基)丙二酸酯-在丙二酸基团中包含一个以上的PTAD部分。