Catalyzed Tandem C–N/C–C Bond Formation for the Synthesis of Tricyclic Indoles using Ir(III) Pyrazolyl-1,2,3-Triazolyl Complexes
作者:Chin Min Wong、Khuong Q. Vuong、Mark R. D. Gatus、Carol Hua、Mohan Bhadbhade、Barbara A. Messerle
DOI:10.1021/om300792b
日期:2012.11.12
C–C bond formation step. The C–N bond formation leading to the formation of indoles was found to proceed via two reaction pathways with 2-(hydroxyalk-1-ynyl)aniline substrates: (a) hydroamination and (b) hydroalkoxylation–Lewis acid mediated isomerization. Pathway (b) is likely to be the main pathway in the formation of indoles starting with 2-(hydroxyalk-1-ynyl)aniline substrates 17S, 18S, and 20S.
通过Cu(I)催化的1-炔丙基吡唑与4-取代的苯基之间的惠斯根环加成反应,制备了一系列新的吡唑基-1,2,3-三唑基N - N'双齿供体配体(2a - c,3a - d)叠氮化物。取代基的吸电子能力遵循趋势PhCH 2 < p -CH 3 Ph 1000 h –1。然而,铱(III)配合物5 - 8被发现是用于串联C-N和C-C键形成的唯一的活性催化剂,因为铑(I)配合物是不为C-C键形成的活性催化剂步。发现导致吲哚形成的C–N键的形成是通过与2-(羟基烷基-1-炔基)苯胺底物的两个反应途径进行的:(a)加氢胺化和(b)加氢烷氧基化-路易斯酸介导的异构化。途径(b)可能是从2-(羟基烷-1-炔基)苯胺底物17S,18S和20S开始形成吲哚的主要途径。