Proton-Promoted Nickel-Catalyzed Asymmetric Hydrogenation of Aliphatic Ketoacids
Proton-Promoted Nickel-Catalyzed Asymmetric Hydrogenation of Aliphatic Ketoacids
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质子促进的镍催化脂肪族酮酸的不对称氢化
DOI：
10.1002/anie.202115983
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发表时间：
2022-02-16
影响因子：
16.6
通讯作者：
Fu, Yao
中科院分区：
文献类型：
--
作者：
Deng, Chen-Qiang;Liu, Jiao;Fu, Yao
发现了一种用于脂肪族γ-和δ-酮酸的不对称氢化的稳定且高活性的均相手性镍-膦络合物。当催化剂用量为0.0133mol%（S/C=7500）时，加氢反应可以顺利进行。用H-1 NMR和HRMS研究了Ni（OTf）（2）与（S，S）-Ph-BPE的配位化学和催化行为。机理研究表明，质子促进了底物C=O键的活化，并通过氢键控制立体选择性。合成了一系列γ-和δ-烷基取代的手性内酯，产率高达98%，对映体选择性高达99%ee。此外，该催化体系还表明，从生物质原料生产的乙酰丙酸转化为手性γ-戊内酯，而没有损失ee值。
A robust and highly active homogeneous chiral nickel-phosphine complex for the asymmetric hydrogenation of aliphatic gamma- and delta-ketoacids has been discovered. The hydrogenation could proceed smoothly in the presence of 0.0133 mol% catalyst loading (S/C=7500). The coordination chemistry and catalytic behavior of Ni(OTf)(2) with (S,S)-Ph-BPE were explored by H-1 NMR and HRMS. The mechanistic studies revealed that a proton promoted the activation of the substrate C=O bond and controlled the stereoselectivity through hydrogen bonds. A series of chiral gamma- and delta-alkyl substituted lactones were obtained in high yields with excellent enantioselectivities (up to 98 % yield and 99 % ee). In addition, this catalytic system also demonstrated that levulinic acid produced from a biomass feedstock was converted into chiral gamma-valerolactone without loss of ee value.