Regioselective Formation of Enol Esters from the Ruthenium-Catalyzed Markovnikov Addition of Carboxylic Acids to Alkynes
作者:Janine Jeschke、Christian Gäbler、Heinrich Lang
DOI:10.1021/acs.joc.5b02293
日期:2016.1.15
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
Ruthenium(IV)-Catalyzed Markovnikov Addition of Carboxylic Acids to Terminal Alkynes in Aqueous Medium
作者:Victorio Cadierno、Javier Francos、José Gimeno
DOI:10.1021/om1010325
日期:2011.2.28
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 propargylicalcohols. In this way, a wide number of enol esters and β-oxoesters could be synthesized in moderate to good yields under mild conditions (60 °C) in an aqueous medium.
Control over C–O and C–C bond formation: ruthenium catalyzed regiospecific addition of carboxylic acid to alkyne and stereoselective dimerization of alkyne
作者:Jyotsna Tripathy、Manish Bhattacharjee
DOI:10.1016/j.tetlet.2009.06.039
日期:2009.8
A cationic ruthenium(II) complex, [Ru(PPh3)2(CH3CN)3Cl][BPh4] (1), has been found to be an effective catalyst for stereoselective dimerization of alkynes in the presence of a base, and for regiospecificaddition of carboxylic acids to alkynes in presence of the Lewis acid, BF3·Et2O.
Carboxylic acid addition to terminal alkynes utilizing ammonium tagged Hoveyda-Grubbs catalyst supported on magnetically separable core/shell silica: A highly reusable and air compatible catalytic system
作者:Bengi Özgün Öztürk、Didar Gürcü、Solmaz Karabulut Şehitoğlu
DOI:10.1016/j.jorganchem.2019.01.005
日期:2019.3
core/shell silica gel was tested on carboxylicacid addition reactions to terminal alkynes using a variety of carboxylicacidderivatives under air atmosphere. The catalytic system was found to be compatible with air atmosphere and can tolerate even non-degassed solvents. The reaction parameters such as temperature, substrate/catalyst ratio and the effect of carboxylicacid on the selectivity and yield of
ruthenium catalyst (Ru/ZrO2) showed activity comparable to that of the ceria-supportedcatalyst. These catalysts were recyclable without a significant loss of activity, and the leaching of ruthenium species into the liquid phase was negligible after cooling the reaction mixture, which indicates marked superiority of the present solid oxide catalysts to conventional homogeneous catalysts.
发现二氧化铈负载的钌催化剂(Ru / CeO 2)对于将各种羧酸加成至末端炔烃是非常有效的,从而以中等至高收率得到了相应的烯醇酯。反应的主要产物是反马尔科夫尼科夫加合物的E-异构体。在所研究的二氧化铈负载的钌催化剂中,使用具有氯化物配体的钌前体制备的催化剂表现出高活性。氧化锆负载钌催化剂(Ru / ZrO 2)显示出与二氧化铈负载的催化剂相当的活性。这些催化剂是可循环使用的,而没有明显的活性损失,并且在冷却反应混合物后,将钌类物质浸入液相中的可能性可忽略不计,这表明本发明的固体氧化物催化剂相对于常规的均相催化剂具有明显的优越性。