Synthetic use of 1,1,2,2-tetraphenyldisilane for the preparation of biaryls through the intramolecular free radical ipso-substitution of N-(2-bromoaryl)arenesulfonamides
摘要:
Treatment of various N-methyl-N-(2-bromoaryl)arenesulfonamides (1a-g, 1i, and 1m) with 1,1,2,2-tetraphenyldisilane and AIBN under heating conditions gave the corresponding biaryl products (2a-g, 2i, and 2m) in moderate yields through the intramolecular radical ipso-substitution. However, N-H foe N-(2-brornoaryl)arenesulfonamides Ih and 2-bromoaryl arenesulfonate 1j did not give the corresponding biarys. 1,1,2,2-Tetraphenyldisilane is the most effective reagent for 1,5-ipso-substitution on the sulfonamides among typical radical reagents such as diphenylsilane, tributyltin hydride, tris(trimethylsilyl)silane, and 1,1,2,2-tetraphenyldisilane. Furthermore, 1,1,2,2 tetraphenyldisilane has the advantages of low toxicity, stability, and ease of preparation. (C) 2001 Elsevier Science Ltd. All rights reserved.
Stereoinversion of Unactivated Alcohols by Tethered Sulfonamides
作者:Paul T. Marcyk、Latisha R. Jefferies、Deyaa I. AbuSalim、Maren Pink、Mu‐Hyun Baik、Silas P. Cook
DOI:10.1002/anie.201812894
日期:2019.2.4
remains an undeveloped area of organic synthesis. Moreover, catalytic activation of this difficult electrophile with predictable stereo-outcomes presents an even more formidable challenge. Described herein is a simple iron-based catalyst system which provides the mild, direct conversion of secondary and tertiary alcohols to sulfonamides. Starting fromenantioenriched alcohols, the intramolecular variant
organosulfur compounds, limited examples of transition-metal-catalyzed thiol-ene reactions have been reported. However, in this work, a directing-group-assisted hydrothiolation of styrenes with thiols by photoredox/cobalt catalysis is found to proceed smoothly to afford Markovnikov-type sulfides with excellent regioselectivity.
One-Pot Synthesis of Indole-3-acetic Acid Derivatives through the Cascade Tsuji–Trost Reaction and Heck Coupling
作者:Dongsheng Chen、Yuanyuan Chen、Zhilong Ma、Lei Zou、Jianqi Li、Yu Liu
DOI:10.1021/acs.joc.8b01056
日期:2018.6.15
palladium-mediated cascade Tsuji–Trost reaction/Heck coupling of N-Ts o-bromoanilines with 4-acetoxy-2-butenonic acidderivatives using a Pd(OAc)2/P(o-tol)3/DIPEA system is described for a straightforward synthesis of indole-3-acetic acidderivatives. This methodology was successfully applied to synthesize various substituted indole/azaindole-3-acetic acidderivatives and Almotriptan, which is a drug for the acute
Tris(trimethylsilyl)silane and visible-light irradiation: a new metal- and additive-free photochemical process for the synthesis of indoles and oxindoles
作者:Gustavo Piva da Silva、Akbar Ali、Rodrigo César da Silva、Hao Jiang、Márcio W. Paixão
DOI:10.1039/c5cc06329a
日期:——
A combined tris(trimethylsilyl)silane and visible-light-promoted intramolecular reductive cyclization protocol for the synthesis of indoles and oxindoles has been developed.
Enantioselective Desymmetrization of Cyclobutanones Enabled by Synergistic Palladium/Enamine Catalysis
作者:Meng Wang、Jun Chen、Zongjia Chen、Changxu Zhong、Ping Lu
DOI:10.1002/anie.201711845
日期:2018.3.1
The enantioselective intramolecular α‐arylation of cyclobutanones has been established by combining palladium and enamine catalyst systems. Two different enantioselective control strategies have been developed for cyclobutanone substrates bearing O‐ or N‐tethered aryl bromides. Further synthetic applications are also reported.