Benzylic C(sp<sup>3</sup>)–C(sp<sup>2</sup>) cross-coupling of indoles enabled by oxidative radical generation and nickel catalysis
作者:Weonjeong Kim、Jangwoo Koo、Hong Geun Lee
DOI:10.1039/d0sc06666d
日期:——
effectively delivered from an aryl (pseudo)halide or an acid anhydride coupling partner, respectively. The developed method utilizes mild conditions and exhibits a wide substrate scope for both substituted indoles and C(sp2)-based reaction counterparts. Mechanisticstudies have shown that competitive hydrogen atom transfer (HAT) processes, which are frequently encountered in conventional methods, are not
among C–H bonds with comparable energetic and steric profiles remains a profound synthetic challenge. Herein, we unveil a site- and stereoselective benzylic C(sp3)–H alkenylation utilizing metallaphotoredox catalysis. Various linear and cyclic (Z)-all-carbon tri- and tetrasubstituted olefins can be smoothly obtained. This strategy can be applied to complex substrates with multiple benzylic sites, previously
Direct C-3 lithiation of 1-(triisopropylsilyl)indole
作者:Mai Matsuzono、Tsutomu Fukuda、Masatomo Iwao
DOI:10.1016/s0040-4039(01)01656-2
日期:2001.10
1-(Triisopropylsilyl)indole can be directly lithiated at 3-position with tort-BuLi-TMEDA in hexane at 0 degreesC for 3 h. The generated lithio species is reacted with a variety of electrophiles to give 3-substituted 1-(triisopropylsilyl)indoles in good yields. (C) 2001 Elsevier Science Ltd. All rights reserved.
Total Synthesis of Verruculogen and Fumitremorgin A Enabled by Ligand-Controlled C–H Borylation
作者:Yu Feng、Dane Holte、Jochen Zoller、Shigenobu Umemiya、Leah R. Simke、Phil S. Baran
DOI:10.1021/jacs.5b07154
日期:2015.8.19
Verruculogen and fumitremorgin A are bioactive alkaloids that contain a unique eight-membered endoperoxide. Although related natural products such as fumitremorgins B and C have been previously synthesized, we report the first synthesis of the more complex, endoperoxide-containing members of this family. A concise route to verruculogen and fumitremorgin A relied not only on a hydroperoxide/indole hemiaminal cyclization, but also on the ability to access the seemingly simple starting material, 6-methoxytryptophan. An iridium-catalyzed C-H borylation/Chan-Lam procedure guided by an N-TIPS group enabled the conversion of a tryptophan derivative into a 6-methoxytryptophan derivative, proving to be a general way to functionalize the C6 position of an N,C3-disubstituted indole for the synthesis of indole-containing natural products and pharmaceuticals.