occurrence of chiral induction involving a hydrogen–hydrogen interaction between a hydride on the iridium atom and the substituent on the oxazoline ring of the ligand, and on the basis of the calculations, we proposed a catalytic cycle involving only Ir(III), which differs from the Ir(III)/Ir(V) catalytic cycle that operates in the hydrogenation of α,β-unsaturated carboxylic acids.
A highly efficient asymmetric hydrogenation of a series of γ-keto acid derivatives, including γ-keto acids, esters, and amides, using a Ni-(R,R)-QuinoxP* complex as the catalyst has been developed to afford chiral γ-hydroxy acid derivatives with excellent enantioselectivities, up to 99.9% ee. This method provides not only an economical one-pot approach for the synthesis of chiral γ-lactones but also
使用 Ni-( R , R )-QuinoxP* 配合物作为催化剂,开发了一系列 γ-酮酸衍生物(包括 γ-酮酸、酯和酰胺)的高效不对称氢化,以提供手性 γ-具有优异对映选择性的羟基酸衍生物,高达 99.9% ee。该方法不仅为合成手性 γ-内酯提供了一种经济的一锅法,而且还提供了 ( S )-去甲氟西汀(一种神经血清素再摄取抑制剂和药物合成的重要中间体)。
Proton‐Promoted Nickel‐Catalyzed Asymmetric Hydrogenation of Aliphatic Ketoacids
作者:Chen‐Qiang Deng、Jiao Liu、Jia‐Hao Luo、Li‐Jin Gan、Jin Deng、Yao Fu
DOI:10.1002/anie.202115983
日期:2022.4.4
A robust and efficient nickel–phosphine complex has been discovered for the asymmetric hydrogenation of aliphatic ketoacids. A proton promoted the activation of C=O bonds and controlled the stereoselectivity through hydrogen bonds to obtain the corresponding products in high yields with excellent enantioselectivities.
An asymmetric, SmI2-mediated approach to γ-butyrolactones using a new, fluorous-tagged auxiliary
作者:Johannes C. Vogel、Rebecca Butler、David J. Procter
DOI:10.1016/j.tet.2008.08.110
日期:2008.12
A new, fluorous-tagged chiral auxiliary has been developed for the asymmetric, SmI2-mediated coupling of aldehydes and alpha,beta-unsaturated esters. gamma-Butyrolactones are obtained in moderate to good isolated yield and in high enantiomeric excess. The fluorous tag allows the auxiliary to be conveniently recovered by fluorous solid-phase extraction (FSPE) and reused. (C) 2008 Elsevier Ltd. All rights reserved.