中国科学院青海盐湖研究所机构知识库
Advanced  
ISL OpenIR  > 青海盐湖研究所知识仓储  > 期刊论文
题名: Mechanism of the Transition-Metal-Catalyzed Hydroarylation ofBromo-Alkynes Revisited: Hydrogen versus Bromine Migration
作者: Huang, Genping ;  Cheng, Bing ;  Xu, Liang ;  Li, Yahong ;  Xia, Yuanzhi
刊名: CHEMISTRY-A EUROPEAN JOURNAL
出版日期: 2012
卷号: 18, 期号:17, 页码:5401-5415
关键词: alkynes ;  cycloisomerization ;  density functional calculations
英文摘要: A comprehensive mechanistic study of the InCl3-, AuCl-, and PtCl2-catalyzed cycloisomerization of the 2-(haloethynyl)biphenyl derivatives of Furstner et al. was carried out by DFT/M06 calculations to uncover the catalyst-dependent selectivity of the reactions. The results revealed that the 6-endo-dig cyclization is the most favorable pathway in both InCl3- and AuCl-catalyzed reactions. When AuCl is used, the 9-bromophenanthrene product could be formed by consecutive 1,2-H/1,2-Br migrations from the Wheland-type intermediate of the 6-endo-dig cyclization. However, in the InCl3-catalyzed reactions, the chloride-assisted intermolecular H-migrations between two Wheland-type intermediates are more favorable. These Cl-assisted H-migrations would eventually lead to 10-bromophenanthrene through proto-demetalation of the aryl indium intermediate with HCl. The cause of the poor selectivity of the PtCl2 catalyst in the experiments by the Furstner group was predicted. It was found that both the PtCl2-catalyzed alkynevinylidene rearrangement and the 5-exo-dig cyclization pathways have very close activation energies. Further calculations found the former pathway would lead eventually to both 9- and 10-bromophenanthrene products, as a result of the Cl-assisted H-migrations after the cyclization of the Ptvinylidene intermediate. Alternatively, the intermediate from the 5-exo-dig cyclization would be transformed into a relatively stable Ptcarbene intermediate irreversibly, which could give rise to the 9-alkylidene fluorene product through a 1,2-H shift with a 28.1 kcal?mol-1 activation barrier. These findings shed new light on the complex product mixtures of the PtCl2-catalyzed reaction. A comprehensive mechanistic study of the InCl3-, AuCl-, and PtCl2-catalyzed cycloisomerization of the 2-(haloethynyl)biphenyl derivatives of Furstner et al. was carried out by DFT/M06 calculations to uncover the catalyst-dependent selectivity of the reactions. The results revealed that the 6-endo-dig cyclization is the most favorable pathway in both InCl3- and AuCl-catalyzed reactions. When AuCl is used, the 9-bromophenanthrene product could be formed by consecutive 1,2-H/1,2-Br migrations from the Wheland-type intermediate of the 6-endo-dig cyclization. However, in the InCl3-catalyzed reactions, the chloride-assisted intermolecular H-migrations between two Wheland-type intermediates are more favorable. These Cl-assisted H-migrations would eventually lead to 10-bromophenanthrene through proto-demetalation of the aryl indium intermediate with HCl. The cause of the poor selectivity of the PtCl2 catalyst in the experiments by the Furstner group was predicted. It was found that both the PtCl2-catalyzed alkynevinylidene rearrangement and the 5-exo-dig cyclization pathways have very close activation energies. Further calculations found the former pathway would lead eventually to both 9- and 10-bromophenanthrene products, as a result of the Cl-assisted H-migrations after the cyclization of the Ptvinylidene intermediate. Alternatively, the intermediate from the 5-exo-dig cyclization would be transformed into a relatively stable Ptcarbene intermediate irreversibly, which could give rise to the 9-alkylidene fluorene product through a 1,2-H shift with a 28.1 kcal?mol-1 activation barrier. These findings shed new light on the complex product mixtures of the PtCl2-catalyzed reaction.
收录类别: SCI
Citation statistics: 
内容类型: 期刊论文
URI标识: http://ir.isl.ac.cn/handle/363002/2060
Appears in Collections:青海盐湖研究所知识仓储(2014年之前)_期刊论文

Files in This Item: Download All
File Name/ File Size Content Type Version Access License
5401_ftp[2].pdf(1543KB)----开放获取
by-nc-sa
View Download

Recommended Citation:
Huang, Genping,Cheng, Bing,Xu, Liang,et al. Mechanism of the Transition-Metal-Catalyzed Hydroarylation ofBromo-Alkynes Revisited: Hydrogen versus Bromine Migration[J]. CHEMISTRY-A EUROPEAN JOURNAL,2012,18(17):5401-5415.
Service
 Recommend this item
 Sava as my favorate item
 Show this item's statistics
 Export Endnote File
Google Scholar
 Similar articles in Google Scholar
 [Huang, Genping]'s Articles
 [Cheng, Bing]'s Articles
 [Xu, Liang]'s Articles
CSDL cross search
 Similar articles in CSDL Cross Search
 [Huang, Genping]‘s Articles
 [Cheng, Bing]‘s Articles
 [Xu, Liang]‘s Articles
Related Copyright Policies
Null
Social Bookmarking
  Add to CiteULike  Add to Connotea  Add to Del.icio.us  Add to Digg  Add to Reddit 
文件名: 5401_ftp[2].pdf
格式: Adobe PDF
所有评论 (0)
暂无评论
 
评注功能仅针对注册用户开放,请您登录
您对该条目有什么异议,请填写以下表单,管理员会尽快联系您。
内 容:
Email:  *
单位:
验证码:   刷新
您在IR的使用过程中有什么好的想法或者建议可以反馈给我们。
标 题:
 *
内 容:
Email:  *
验证码:   刷新

Items in IR are protected by copyright, with all rights reserved, unless otherwise indicated.

 

 

Valid XHTML 1.0!
Copyright © 2007-2016  中国科学院青海盐湖研究所 - Feedback
Powered by CSpace