Rhodium(III)-Catalyzed CH Activation and Indole Synthesis With Hydrazone as an Auto-Formed and Auto-Cleavable Directing Group
作者:Liyao Zheng、Ruimao Hua
DOI:10.1002/chem.201304302
日期:2014.2.17
An efficient, practical, and external‐oxidant‐free indolesynthesis from readily available aryl hydrazines was developed, by using hydrazone as a directing group for RhIII‐catalyzed CHactivation and alkyne annulation. The hydrazone group was formed by in situ condensation of hydrazines and CO source, whereas its NN bond was served as an internal oxidant, for which we termed it as an auto‐formed
valuable molecules requires a multistep sequence. Therefore, a simple, one-step protocol to access libraries of polyaromatic indole scaffolds is highly desirable. Herein we describe the direct synthesis of polysubstituted indolo[2,1-a]isoquinoline analogues via a double C–H annulation cascade using triazene as an internally cleavable directing group. Evidence from HRMS and theoretical calculations suggests
Ruthenium(II)-Catalyzed Oxidative Double C–H Activation and Annulation Reaction: Synthesis of Indolo[2,1-<i>a</i>]isoquinolines
作者:Somadrita Borthakur、Bipul Sarma、Sanjib Gogoi
DOI:10.1021/acs.orglett.9b02871
日期:2019.10.4
The first metal-catalyzed double aryl C(sp2)-H bond activation of antipyrine and alkyne annulation reaction is reported. This Ru(II)-catalyzed reaction was accomplished in the presence of 20 mol % phosphine ligand tricyclohexylphosphine tetrafluoroborate to afford indolo[2,1-a]isoquinolines that are very important compounds because of their bioactivity and interesting optical properties.
Selective Synthesis of <i>N</i>-Unsubstituted and <i>N</i>-Arylindoles by the Reaction of Arynes with Azirines
作者:Manikandan Thangaraj、Sachin Suresh Bhojgude、Shailja Jain、Rajesh G. Gonnade、Akkattu T. Biju
DOI:10.1021/acs.joc.6b01472
日期:2016.9.16
transition-metal-free and temperature-dependent highly selective reaction of arynes with 2H-azirines allowing the synthesis of either N-unsubstituted or N-arylindoles has been developed. At 60 °C, arynes generated from 2-(trimethylsilyl)aryl triflates smoothly insert into 2H-azirines to form 2,3-diarylindoles with high selectivity. Interestingly, when the reaction was performed at −10 °C, the selectivity was switched
convenient Rh(III)-catalyzed double aryl C(sp2)–H bond and N–H activation and annulationreaction is reported for the synthesis of indolo[2,1-a]isoquinolines in the presence of the Cu(OAc)2 oxidant under heating conditions. Distinct from previous works with other arylamine donors, one molecule of 1,3-diarylurea can serve as a precursor of two molecules of arylamine in the reaction with diaryl-substituted