Group VIII carbamoyl complexes as catalysts for alkyne hydrocarboxylation and electrochemical proton reduction
作者:Chandan Kr Barik、Malcolm E. Tessensohn、Richard D. Webster、Weng Kee Leong
DOI:10.1016/j.jorganchem.2019.03.019
日期:2019.7
A series of group VIII carbamoyl complexes, [M(2-NHC(O)C5H4N)(CO)2(2-SC5H4N)] [where M = Fe, Ru and Os], was found to be efficient and regioselective catalysts for the intramolecular hydroxycarboxylation of α,ω-alkynoic acids, yielding exocyclic enol lactones for ring sizes up to 7 atoms, and endocyclic enol lactones for ring sizes up to 12 atoms. They also catalysed the regioselective intermolecular
发现了一系列的VIII族氨基甲酰基配合物,[M(2-NHC(O)C 5 H 4 N)(CO)2(2-SC 5 H 4 N)] [其中M = Fe,Ru和Os]是有效的区域选择性催化剂,可用于α,ω-链烷酸的分子内羟基羧化反应,可制得环尺寸最大为7个原子的环外烯醇内酯,而环尺寸最大可形成12个原子的内环烯醇内酯。他们还催化了炔丙醇和羧酸之间的区域选择性分子间羟基羧化反应,形成β-氧代酯。这些络合物还可以在质子还原中充当电催化剂,对其氧化还原电位的评估表明,铁络合物比钌或类似物的效率要高得多。
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。