A Transition-Metal-Catalyzed Enediyne Cycloaromatization
摘要:
The pentamethylcyclopentadienyl iron cation, generated from [(eta5-C5Me5)Fe(NCMe)3]PF6, triggers the room temperature cycloaromatization of acyclic and alicyclic enediynes, in the presence of either 1,4-cyclohexadiene or terpinene as the hydrogen-atom donor, to give metal-arene products in good to excellent yields. Photolysis of the metal-arene complexes liberates the arene from the metal in excellent yield. The first demonstration of a transition-metal-catalyzed cycloaromatization of conjugated enediynes has been achieved under photochemical conditions utilizing either [(eta5-C5Me5)Fe(NCMe)3]PF6 or [(eta5-C5Me5)Fe(eta6-1,2-(Prn)2C6H4)]PF6 as the catalyst precursor. The use of a metal and light has led to a convenient method for cycloaromatization of a trans-enediyne.
Kinetic evidence for the formation of discrete 1,4-dehydrobenzene intermediates. Trapping by inter- and intramolecular hydrogen atom transfer and observation of high-temperature CIDNP
作者:Thomas P. Lockhart、Paul B. Comita、Robert G. Bergman
DOI:10.1021/ja00404a018
日期:1981.7
LBL-11696 Pre print Submitted to the Journal of the American Chemical Society KINETIC EVIDENCE FOR THE FORMATION OF DISCRETE 1,4-DEHYDROBENZENE INTERMEDIATES. TRAPPING BY INTER- AND INTRAMOLECULAR HYDROGENATOMTRANSFER AND OBSERVATION OF HIGH-TEMPERATURE CIDNP. Thomas P. Lockhart. Paul B. Comita, and Robert C. Bergman September 1980 TWO-WEEK LOAN COPY Thi~ is a Library Circulating Copy wh1ch may b
LBL-11696 预印本已提交至美国化学学会杂志 离散 1,4-脱氢苯中间体形成的动力学证据。通过分子间和分子内氢原子转移的捕获和高温 CIDNP 的观察。托马斯·P·洛克哈特。Paul B. Comita 和 Robert C. Bergman 1980 年 9 月 两周借阅本 这是一本图书馆的流通本,可借阅两周。个人保留副本)> 致电技术人员。信息。Division )> 根据合同 W-7405-ENG-48 为美国能源部准备
Catalytic dehydroaromatization of n-alkanes by pincer-ligated iridium complexes
作者:Ritu Ahuja、Benudhar Punji、Michael Findlater、Carolyn Supplee、William Schinski、Maurice Brookhart、Alan S. Goldman
DOI:10.1038/nchem.946
日期:2011.2
important building blocks in the chemical industry. Benzene, toluene and xylenes are obtained from the high temperature thermolysis of alkanes. Higher alkylaromatics are generally derived from arene–olefin coupling, which gives branched products—that is, secondary alkyl arenes—with olefins higher than ethylene. The dehydrogenation of acyclic alkanes to give alkylaromatics can be achieved using heterogeneous
Selective Mono-Alkylation and Arylation of Dichlorobenzenes by Palladium-Catalyzed Grignard Cross-Coupling
作者:Tatsuo Katayama、Masayuki Umeno
DOI:10.1246/cl.1991.2073
日期:1991.11
Palladium(II)–phosphine complexes, especially PdCl2(dppf) where dppf stands for 1,1′-bis(diphenylphosphino)ferrocene, are effectivecatalysts for the cross-coupling of Grignardreagents with dichlorobenzenes to produce selectively mono-alkylated and arylated benzenes. The addition of ligands is also effective for the cross-coupling of Grignardreagents containing a β-hydrogen(s).
[EN] BENZOTHIAZOLE DERIVATIVES HAVING BETA-2-ADRENORECEPTOR AGONIST ACTIVITY<br/>[FR] DERIVES DE BENZOTHIAZOLE AYANT UNE ACTIVITE D'AGONISTE DU BETA-2-ADRENORECEPTEUR
申请人:NOVARTIS AG
公开号:WO2004016601A1
公开(公告)日:2004-02-26
Compounds of Formula (I) in free or salt or solvate form, wherein X has the meaning indicated in the specification, are useful for treating conditions that are prevented or alleviated by activation of the ß2-adrenoreceptor. Pharmaceutical compositions that contain the compounds and processes for preparing the compounds are also described.
Regioselective Bromomethylation of 1,2-Dialkylbenzenes
作者:Nupur Garg、T. Randall Lee
DOI:10.1055/s-1998-1634
日期:1998.3
This paper describes a systematic exploration of the regioselective bromomethylation of 1,2-dialkylbenzenes as a function of the reaction temperature and the chain length of the alkyl groups. At both 80 and 110 °C, bromomethyl groups can be introduced into the 4 and 5 positions of 1,2-dialkylbenzenes with high selectivity when the alkyl chains consist of two or more carbon atoms.