Platinum and Ruthenium Chloride-Catalyzed Cycloisomerization of 1-Alkyl-2-ethynylbenzenes: Interception of π-Activated Alkynes with a Benzylic C−H Bond
摘要:
Air-stable and commercially available alkynophilic metal salts, such as PtCl2, PtCl4, and [RuCl2(CO)(3)](2), catalyze the cycloisomerization of 1-alkyl-2-ethynylbenzenes to produce Substituted indenes even at all ambient temperature. Electrophilically activated alkynes can be intercepted by simple benzylic C-H bonds at primary, secondary, and tertiary carbon centers. Mechanistic studies, such as labeling studies and kinetic isotope and substituent effects, indicate that the cycloisomerization proceeds through the formation of a vinylidene intermediate and turnover-limiting 1,5-shift of benzylic hydrogen.
Synthesis of [1,2,3]-triazolo[1,5-a][1,4]benzodiazepines via an unprecedented one-pot Cu-catalyzed azidation–cyclization reaction
作者:Geert Hooyberghs、Hendrik De Coster、Dipak D. Vachhani、Denis S. Ermolat'ev、Erik V. Van der Eycken
DOI:10.1016/j.tet.2013.03.031
日期:2013.5
A novel three-step approach leading to [1,2,3]-triazolo[1,5-a][1,4]benzodiazepines in moderate to good yields has been developed. The key step is an unprecedented one-pot Cu-catalyzed azidation–cyclization reaction of ortho-bromobenzylpropargylamines.
已经开发出一种新颖的三步法,以中等到良好的产率产生[1,2,3]-三唑并[1,5- a ] [1,4]苯并二氮杂s。关键步骤是空前的一锅Cu催化邻溴代苄基炔丙基胺的叠氮化-环化反应。
The 1,7-cyclohexenonorbornadiene system
作者:Leo A. Paquette、Tina M. Kravetz、Pana Charumilind
DOI:10.1016/s0040-4020(01)87596-7
日期:1986.1
anion, namely 9, provides fulvenes of type 3 on workup. The use of 3 as a diene in Diels-Alder cycloadditions is demonstrated by the condensation of methylderivative 3a with dimethyl acctylenedicarboxylate and (E)-1,2-bis(phenylsulfonyl)ethylene. The question of face selectivity is raised. For the bissulfone adducts 21 and 22, reductive desulfonylation with 1–2% sodium amalgam delivers hydrocarbon
Platinum and Ruthenium Chloride-Catalyzed Cycloisomerization of 1-Alkyl-2-ethynylbenzenes: Interception of π-Activated Alkynes with a Benzylic C−H Bond
作者:Mamoru Tobisu、Hiromi Nakai、Naoto Chatani
DOI:10.1021/jo901045g
日期:2009.8.7
Air-stable and commercially available alkynophilic metal salts, such as PtCl2, PtCl4, and [RuCl2(CO)(3)](2), catalyze the cycloisomerization of 1-alkyl-2-ethynylbenzenes to produce Substituted indenes even at all ambient temperature. Electrophilically activated alkynes can be intercepted by simple benzylic C-H bonds at primary, secondary, and tertiary carbon centers. Mechanistic studies, such as labeling studies and kinetic isotope and substituent effects, indicate that the cycloisomerization proceeds through the formation of a vinylidene intermediate and turnover-limiting 1,5-shift of benzylic hydrogen.