Regiocontrolled direct C4 and C2-methyl thiolation of indoles under rhodium-catalyzed mild conditions
作者:Saurabh Maity、Ujjwal Karmakar、Rajarshi Samanta
DOI:10.1039/c7cc07086a
日期:——
Rh(III)catalyzed general strategy was developed for the site selective remote C4 (sp2) and C2 (sp3)-methyl thiolation of indole core keeping the oxime directing group at the C3 position. The transformation was accomplished undermildconditions with wide scope and functional group tolerance. The directing group can easily be removed after operation. Methyl substitution at the C2 position of indole core
Novel and Simple Methodology for the Synthesis of 3-Acetylindoles and their N-Alkyl Derivatives Using TBAB as Phase Transfer Catalyst
作者:M. Venkatanarayana、Pramod K. Dubey
DOI:10.2174/157017811799304395
日期:2011.11.1
Using 5% aq. NaOH, a simple method for the transformation of 3-cyanoacetylindoles 2(a-e) into 3- acetylindoles 3 (a-e), in good yields, is reported. Tetrabutylammoniumbromide (TBAB) is found to be an efficient phase transfer catalyst for the synthesis of N-alkyl derivatives 5(a-t) of 3-acetylindoles 3(a-e) giving products in excellent yields. 2 (a-e) were themselves obtained from simple indoles 1 (a-e) by reaction with cyano acetic acid in the presence of propionic anhydride at 100 °C for 5-10 min. Partial hydrolysis of 2 (a-e) under hot acidic conditions yielded the corresponding carboxamides α-(3-indolecarboxoyl)acetamides 4(a-e). Which could be readily transformed into the respective 3(a-e) by refluxing with 5% aq. NaOH for 2-2.5 h.
A weak carbonyl coordination-guided regioselective C4 allylation of indoles is demonstrated using the versatile Morita-Baylis-Hillman adduct in the presence of Rh catalysts in a redox-neutral fashion. The substrate scope, functional group diversity, oxidant free character, mechanistic aspects, and synthetic utilities are important practical features.
coordination facilitated tunable reactivity between alkenylation and alkylation of indoles at the C4 C-H site is presented using readily accessible allylic alcohols in the presence of Rh catalysis by switching the additives or directing group. Exclusive site selectivity, functional group tolerance, and late-stage modifications are the important practical features.
Cascade Reaction to Selectively Synthesize Multifunctional Indole Derivatives by Ir
<sup>III</sup>
‐Catalyzed C−H Activation
作者:Xin‐Yue Chai、Hui‐Bei Xu、Lin Dong
DOI:10.1002/chem.202101602
日期:2021.9.15
way to synthesize with high selectivity a variety of functionalized indoles with potent biological properties has been developed. Notably, 2,4-dialkynyl indole products were obtained by direct double C−H bond alkynylation, whereas alkynyl at the C4 position could convert to carbonyl to generate 2-alkynyl-3,4-diacetyl indoles fast and effectively. Additionally, a one-pot relay catalytic reaction led to