A parahydrogen based NMR study of Pt catalysed alkyne hydrogenation
作者:Marie Boutain、Simon B. Duckett、John P. Dunne、Cyril Godard、José M. Hernández、A. Jonathan Holmes、Iman G. Khazal、Joaquín López-Serrano
DOI:10.1039/b925196k
日期:——
A parahydrogen based NMR study of the platinum(II) bis-phosphine triflate catalysed hydrogenation of alkynes in methanol reveals that platinum bis-phosphine alkyl cations and methanol functionalised platinum bis-phosphine alkylether cations, are responsible for the observed alkene and vinylether products.
Dichotomous Reactivity in the Reaction of Triethyl- and Triphenylphosphane HBr Salts with Dimethyl Acetals: A Novel Entry to α-Alkoxy-Functionalized Ylides and General Synthesis of Vinyl Ethers and Alkoxy Dienes
作者:Priyabrata Das、James McNulty
DOI:10.1002/ejoc.201000601
日期:2010.7
discovery of dichotomousreactivity in the reaction of trialkyl- vs. triphenylphosphaneHBrsalts with acetals allows entry to functionalized α-methoxy phosphonium salts and a novel process for tertiary phosphane methylation. The new protocol opens a generalentry to the synthesis of vinylethers and differentially substituted 1,3-dienes via Wittig reactions of the functionalized ylides derived from
[(NHC)Au<sup>I</sup>]-Catalyzed Acid-Free Alkyne Hydration at Part-per-Million Catalyst Loadings
作者:Nicolas Marion、Rubén S. Ramón、Steven P. Nolan
DOI:10.1021/ja809403e
日期:2009.1.21
highly efficient [(NHC)Au(I)]-based (NHC = N-heterocyclic carbene) catalytic system for the hydration of an array of alkynes that operates under acid-free conditions and at very low catalystloadings (typically 50-100 ppm and as low as 10 ppm) was developed. Terminal and internal alkynes possessing any combination of alkyl and aryl substituents (alkyl/H, aryl/H, alkyl/alkyl, alkyl/aryl, and aryl/aryl)
Reduction of titanocene dichloride with dysprosium: access to a stable titanocene(<scp>ii</scp>) equivalent for phosphite-free Takeda carbonyl olefination
A new titanocene(ii) equivalent obtained from the reduction of titanocene dichloride with dysprosium allows phosphite-free and simplified Takeda carbonyl olefination reactions.
Functionalization of Alkynes Catalyzed byt-Bu-P4 Base
作者:Tatsushi Imahori、Chieko Hori、Yoshinori Kondo
DOI:10.1002/adsc.200404076
日期:2004.8
The addition of O- and N-nucleophiles to alkynescatalyzed by a phosphazene base, t-Bu-P4 base, was investigated. Alkynes were easily transformed to enol ethers and enamines in DMSO by the addition of nucleophiles. When phenylacetylene was reacted with diisopropylamine, a unique head-to-head dimerization of phenylacetylene was observed to give the enyne derivative. Terminal proton of phenylacetylene