Selective Dimerisation and Addition of Carboxylic Acids to Terminal Alkynes, Catalysed by Thermolysed Grubbs’ Catalyst: A Novel Synthesis of Enynes and Vinyl Esters
Carboxylic acids react with terminalalkynes in the presence of a catalytic amount of RuClx(p-cymene)(triazol-5-ylidene) to selective generate Z-alk-1-en-1-yl esters. The anti-Markovnikov and trans addition on the terminalalkyne gives access to Z-alkene derivatives of phenylacetylene, t-butylacetylene, 1-octyne, 4-pentynoic acid and 1,7-octadiyne. The dimerization of terminalalkynes catalyzed with the same
Atom transfer radical addition and enol-ester synthesis catalyzed by Ru–vinylidene complexes
作者:Tom Opstal、Francis Verpoort
DOI:10.1016/s0040-4039(02)02233-5
日期:2002.12
L) (L=PCy3 or N-heterocyclic carbenes) reveal themselves as a versatile catalyst for the atom transfer radicaladdition (ATRA) of polyhalogenated alkanes to olefins, such as methylmethacrylate, styrene and 1-octene. Furthermore, these systems are excellent catalysts for the nucleophilic addition of carboxylic acids to terminal alkynes and yielded exclusively alk-1-en-2-yl esters. These complexes can
Synthesis of Enol Esters and Dimerization of Terminal Alkynes Catalyzed by Neutral and Cationic Vinylidene Ruthenium Complexes
作者:Francis Verpoort、Tom Opstal
DOI:10.1055/s-2003-37106
日期:——
In the current study Ru(II) vinylidene complexes of the general type: Cl 2 Ru=C=C(H)R}(PR' 3 )L (R = Ph, SiMe 3 , R'=Ph, Cyclohexyl (Cy) and L = phosphine or N-heterocyclic carbene) are synthesized and tested for the addition of carboxylic acids to terminalalkynes. A careful choice of the catalytic system, substrate and carboxylic acid gives access to alk-1-en-2-yl esters, alk-1-en-1-yl esters or
Catalytic application of a Ru-alkylidene in the nucleophilic addition of several carboxylic acids on terminal alkynes and the homo-coupling of 1-alkynes
作者:Karen Melis、Dirk De Vos、Pierre Jacobs、Francis Verpoort
DOI:10.1016/s0022-328x(03)00074-3
日期:2003.4
Thermal treatment of Ru-alkylidene (4) bearing a triazol-5-ylidene (NHC) ligand (2) at 110 degreesC and addition of a terminal alkyne generates a ruthenium vinylidene. The thermolysed Ru-alkylidene catalyses the vinylation and dimerisation of 1-alkynes. The nucleophilic addition of acetic acid on terminal alkynes proceeds smoothly and regioselective towards the Markovnikov addition. The addition reaction can be tuned by changing the acidity of the carboxylic acid. At increasing acidity, higher conversion of the triple bond is obtained and the vinylation/dimerisation ratio increases. The direct coupling between two 1-alkynes shows a reactivity order, which decreases from 1-octyne > 1,7-octadiyne > phenylacetylene > 3,3 dimethyl-1-butyne. The regioselectivity is strongly dependent on the nature of the terminal alkyne. (C) 2003 Elsevier Science B.V. All rights reserved.