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。
Ligand and Substrate Effects on Regio‐ and Stereoselective Ru(II)‐Catalyzed Hydroacyloxylations to Vinylic Esters
作者:Paul A. Beasley、Frank E. McDonald
DOI:10.1002/adsc.202301222
日期:2024.2.20
Two Ru(II)-catalytic systems were developed for anti-Markovnikov regioselective hydroacyloxylations of terminal alkynes to vinylic esters. [Ru(NCCH3)6][(BF4)2] favors (E)-vinylic ester products with arylacetylenes and select carboxylic acids, whereas a Ru scorpionate complex with two electron-withdrawing ligands favors (Z)-vinylic ester isomers.
Steric Control at the Wingtip of a Bis-N-Heterocyclic Carbene Ligand: Coordination Behavior and Catalytic Responses of Its Ruthenium Compounds
作者:Sayantani Saha、Tapas Ghatak、Biswajit Saha、Henri Doucet、Jitendra K. Bera
DOI:10.1021/om300469n
日期:2012.8.13
crystallization in air, where both ligands show normal C2/C2 coordination. Thus, the resulting complexes exhibit different structural and electronic characteristics, which are further reflected in their catalytic responses. The catalytic utilities of both compounds toward carboxylic acid addition onto terminal alkyne are evaluated in this work. The abnormally bound 1 shows higher activity and better selectivity
将亚甲基连接的双-NHC配体的N-取代基从正丁基改变为庞大的均二甲苯基使配体配位从正常/正常模式转变为正常/异常模式。均三级翼尖基团提供[Ru II(Mes NHC(CH 2)NHC Mes)(Mes NHC(CH 2)a NHC Mes)(CH 3 CN)2 ] [PF 6 ] 2(1),其中一个是配体表现出混合的C 2 / C 4与相同金属的结合,而第二个配体利用C 2 / C 2用于金属配位的碳。相反,正丁基类似物导致金属氧化,在空气中结晶时会提供Ru III络合物[Ru(n Bu NHC(CH 2)NHC n Bu)2 Cl 2 ] [PF 6 ](2)。两种配体均显示正常的C 2 / C 2配位。因此,所得的配合物表现出不同的结构和电子特性,这进一步反映在它们的催化反应中。在这项工作中,评估了这两种化合物对羧酸加成至末端炔烃的催化作用。异常绑定图1显示了与所有正常对应物2相比更高的活性和更好的选择性。