95865-57-9Relevant academic research and scientific papers
Selective Addition of Unsaturated Carboxylic Acids to Terminal Acetylenes Catalyzed by Bis(η5-cyclooctadienyl)ruthenium(II)-Tri-n-butylphosphine. A Novel Synthesis of Enol Esters
Mitsudo, Take-aki,Hori, Yoji,Watanabe, Yoshihisa
, p. 1566 - 1568 (1985)
Unsaturated carboxylic acids such as methacrylic acid, crotonic acid, vinylacetic acid, and sorbic acid and aromatic carboxylic acids reacted with terminal acetylenes in the presence of a catalytic amount of bis(η5-cyclooctadienyl)ruthenium-P-n
Regioselective Formation of Enol Esters from the Ruthenium-Catalyzed Markovnikov Addition of Carboxylic Acids to Alkynes
Jeschke, Janine,G?bler, Christian,Lang, Heinrich
, p. 476 - 484 (2016/01/25)
The ruthenium complexes [Ru(CO)2(P(p-C6H4-X)3)2(O2CPh)2] (1a, X = CF3; 1b, X = Cl; 1c, X = H; 1d, X = Me; 1e, X = OMe) were successfully applied in the regioselective Markovnikov addition of carboxylic acids to terminal alkynes, yielding valuable enol esters. Catalyst screening revealed a significant influence of phosphine's electronic nature on activity and selectivity. The highest activity was achieved with catalyst 1a, featuring the most electron-withdrawing phosphine ligand. Selectivity and activity could be further improved by the addition of catalytic amounts of AgOTf. Moreover, excellent selectivities with up to 99% of the Markovnikov product were achieved. The electronic influence of the substrates on the reaction rate was quantified by Hammett plots. By the use of electron-rich alkynes or highly acidic carboxylic acids, the reaction rate could be increased. Hence, the addition of highly acidic pentafluorobenzoic acid to electron-rich 4-methoxyphenylacetylene can even be carried out quantitatively at 25°C within 4 h. Furthermore, a broad range of simple as well as electronically or sterically challenging substrates could be isolated in good to excellent yields with high regioselectivity and under mild reaction conditions (25-70°C). The best reported activities and selectivities were obtained for the conversion of aromatic alkynes.
Asymmetric hydrogenation of 1-alkyl and 1-aryl vinyl benzoates: A broad scope procedure for the highly enantioselective synthesis of 1-substituted ethyl benzoates
Kleman, Patryk,Gonzlez-Liste, Pedro J.,Garca-Garrido, Sergio E.,Cadierno, Victorio,Pizzano, Antonio
, p. 4398 - 4408 (2015/02/05)
The enantioselective hydrogenation of enol esters of formula CH2=C(OBz)R with rhodium catalysts based on phosphine-phosphite ligands (P-OP) has been studied. The reaction has a broad scope, and it is suitable for the preparation of products pos
Highly enantioselective Rh-catalysed hydrogenation of 1-alkyl vinyl esters using phosphine-phosphoramidite ligands
Konrad, Tina Maria,Schmitz, Pascal,Leitner, Walter,Francio, Giancarlo
supporting information, p. 13299 - 13303 (2013/10/08)
MatPhos, a good mate for hard tasks: The asymmetric hydrogenation of 1-alkyl vinyl esters, thwarted so far by mediocre ee values and low activities, can now be achieved with MatPhos/Rh catalysts with ee values of 96-99 % for a variety of substrates at low catalyst loadings (0.1-1 mol %) and under mild conditions (5-20 bar H2, room temperature). After hydrolysis, the corresponding chiral secondary alkyl alcohols can be obtained in high enantiopurities providing a general and practical route to this important product class. Copyright
Highly enantioselective hydrogenation of 1-alkylvinyl benzoates: A simple, nonenzymatic access to chiral 2-alkanols
Kleman, Patryk,González-Liste, Pedro J.,García-Garrido, Sergio E.,Cadierno, Victorio,Pizzano, Antonio
supporting information, p. 16209 - 16212 (2013/12/04)
Going chiral! Highly enantioselective catalytic hydrogenations of enol esters 1 by using a Rh catalyst bearing a P?£?OP ligand are described (see scheme; NBD=norbornadiene). The catalytic system has a broad scope and allows the preparation of a wide range of chiral esters 2 bearing diverse alkyls or a benzyl group with high enantioselectivities. These esters can easily be converted in highly enantioenriched 2-alkanols. Copyright
Ruthenium(IV)-catalyzed markovnikov addition of carboxylic acids to terminal alkynes in aqueous medium
Cadierno, Victorio,Francos, Javier,Gimeno, Jose
experimental part, p. 852 - 862 (2011/04/15)
The dimeric bis(allyl)ruthenium(IV) complex [{RuCl(μ-Cl)( η3:η3-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) (5) and several mononuclear species trans-[RuCl2(η3: η3-C10H16)(L)] (L = two-electron-donor ligand) (6) derived from 5 have been checked as catalysts for the addition of carboxylic acids onto terminal alkynes using water as a green reaction medium. The best results in terms of activity and regioselectivity were obtained with the mononuclear derivative trans-[RuCl2(η3: η3-C10H16)(PPh3)] (6a), which was able to promote the selective Markovnikov addition of both aromatic and aliphatic carboxylic acids to a large variety of terminal alkynes, enynes, and diynes as well as propargylic alcohols. In this way, a wide number of enol esters and β-oxo esters could be synthesized in moderate to good yields under mild conditions (60 °C) in an aqueous medium.
Ruthenium-Catalyzed Selective Addition of Carboxylic Acids to Alkynes.A Novel Synthesis of Enol Esters
Mitsudo, Take-aki,Hori, Yoji,Yamakawa, Yasushi,Watanabe, Yoshihisa
, p. 2230 - 2239 (2007/10/02)
Carboxylic acids react with alkynes in the presence of a catalytic amount of bis(ν5-cyclooctadienyl)ruthenium/trialkylphosphine/maleic anhydride in toluene at 60-80 deg.C to give enol esters having a terminal methylene group in good to excellent yields with high regioselectivity.The deuterium distributions in the products of the reaction of acetic acid-d with 1-hexyne and ethyl propargyl carbonate were examined.Kinetic measurments revealed that the rate has first-order dependence on carboxylic acid, alkyne, and the initial concentration of the ruthenium catalyst.
