Intensification of the use of ionic liquids as efficient reaction co-solvents in asymmetric hydrogenations

Ionic Liquids in Asymmetric Synthesis: An Overall View from Reaction Media to Supported Ionic Liquid Catalysis

“…In 2011, ar esearch group led by Kluson studied the effect of ionic liquid impurities on the reactione fficiency in the enantioselectiveh ydrogenation of methyl-3-oxobutanoate over the [RuCl{(R)-BINAP}(p-cymene)]Cl catalyst in an ethanol/[Bmim] [PF 6 ]b iphasic system. [38] The results show that only at race impurity in the ionic liquid decreases the ee value from 97 to 25-85 %d epending on the nature of the contamination of ap articular supply.T herefore, they demonstrate that the purity of the ionic liquid as the solvent is not anegligible issue.…”

Research Advances of the Chiral Binap-Ru(II) Catalysts in Asymmetric Hydrogenation Reactions

“…该结果与 Takaya 课 题组 [37] 对复杂 β-酮酯分子的一致. [45] 和乙醇-bmimPF 6 (41) [46] 混合相 中催化乙酰乙酸甲酯加氢, 发现这两种催化体系均表现 出非常优秀的对映体选择性. 2013 年, Leitner 课题组 [47] 2016 年, Baratta 课题组 [48] 在三乙胺存在下, 使用…”

Integration of a chiral phosphine ligand and ionic liquids: sustainable and functionally enhanced BINAP-based chiral Ru(ii) catalysts for enantioselective hydrogenation of β-keto esters

“…Ionic liquids (ILs) have attracted increasing attention as carriers for the separation, recovery and recycling of chiral catalysts because of their attractive properties, such as extremely low vapor pressure, high thermal and chemical stability, good solubility for transition metal catalysts, and structure designability. 3 In academia, some successful applications of ILs as catalyst carriers have been reported in the asymmetric hydrogenations of α-enamides 4 or imines, 5 α- 6 or β-ketoesters, 4 g ,6 a ,7 simple ketones, 8 α,β-unsaturated ketones, 9 2-arylacrylic acids, 10 itaconate esters 4 g ,11 and acetyltrimethylsilane. 12 However, a large amount of carrier IL was routinely used, which led to the reduction of catalytic activity and stereoselectivity 4 a , c – g ,7 b , d – f ,10,13 and violated green chemistry practices, 14 hindering the practical application of ILs.…”