Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Esters with Chiral Iridium N,P Ligand Complexes
作者:David H. Woodmansee、Marc-André Müller、Lars Tröndlin、Esther Hörmann、Andreas Pfaltz
DOI:10.1002/chem.201202397
日期:2012.10.22
Enantioselective conjugate reduction of a wide range of α,β‐unsaturated carboxylicesters was achieved using chiral Ir N,P complexes as hydrogenation catalysts. Depending on the substitution pattern of the substrate, different ligands perform best. α,β‐Unsaturated carboxylicesters substituted at the α position are less problematic substrates than originally anticipated and in some cases α‐substituted
A highly enantioselective hydrogenation of exocyclic α,β-unsaturatedcarbonylcompounds catalyzed by Rh/bisphosphine-thiourea (ZhaoPhos) has been developed, giving the corresponding α-chiral cyclic lactones, lactams and ketones with high yields and excellent enantioselectivities (up to 99% yield and 99% ee). Remarkably, the hydrogen bond between the substrate and the catalyst plays a critical role
SpinPhox/Iridium(I)-Catalyzed Asymmetric Hydrogenation of Cyclic α-Alkylidene Carbonyl Compounds
作者:Xu Liu、Zhaobin Han、Zheng Wang、Kuiling Ding
DOI:10.1002/anie.201309521
日期:2014.2.10
cyclic carbonyl compounds bearing an α‐chiral carbon center are of interest in pharmaceutical sciences and asymmetric synthesis. Herein, SpinPhox/IrI catalysts have been demonstrated to be highly enantioselective in the asymmetric hydrogenation of the CC bonds in the exocyclicα,β‐unsaturated cyclic carbonyls, including a broad range of α‐alkylidene lactams, unsaturated cyclic ketones, and lactones. It
带有α-手性碳中心的旋光中型环状羰基化合物在制药科学和不对称合成中引起人们的兴趣。在本文中,SpinPhox / Ir I催化剂在环外α,β-不饱和环状羰基化合物(包括各种α-亚烷基内酰胺,不饱和环状酮)中的CC键的不对称氢化中被证明具有高度对映选择性。内酯。值得注意的是,该方法可以成功地用于具有六元或七元环的具有挑战性的α-烷基亚内酰胺底物的不对称氢化,从而提供相应的具有α-手性碳中心的旋光羰基化合物,其对映体过量通常非常好(高达ee的98% )。该协议的合成用途还已在抗炎药洛索洛芬及其类似物以及生物学上重要的ε-氨基己酸衍生物的不对称合成中得到证明。
Design of oxa-spirocyclic PHOX ligands for the asymmetric synthesis of lorcaserin <i>via</i> iridium-catalyzed asymmetric hydrogenation
Phosphine–oxazoline (PHOX) ligands are a very important class of privileged ligands in asymmetric catalysis. A series of highlyrigid oxa-spiro phosphine–oxazoline (O-SIPHOX) ligands based on O-SPINOL was synthesized efficiently, and their iridium complexes were synthesized by coordination of the O-SIPHOX ligands to [Ir(cod)Cl]2 in the presence of sodium tetrakis-3,5-bis(trifluoromethyl)phenylborate
Mechanism of the Asymmetric Hydrogenation of Exocyclic α,β-Unsaturated Carbonyl Compounds with an Iridium/BiphPhox Catalyst: NMR and DFT Studies
作者:Yuanyuan Liu、Ilya D. Gridnev、Wanbin Zhang
DOI:10.1002/anie.201309677
日期:2014.2.10
mechanism of the asymmetric hydrogenation of exocyclicα,β‐unsaturated carbonyl compounds with the (aS)‐Ir/iPr‐BiphPhox catalyst was studied by NMR experiments and DFT computational analyses. Computed optical yields of the asymmetric hydrogenation proceeding by an iridium(I)/iridium(III) mechanism involving a transition state stabilized through two intramolecular hydrogen bonds are in good accordance
通过NMR实验和DFT计算分析研究了(aS)-Ir / i Pr-BiphPhox催化剂对环外α,β-不饱和羰基化合物不对称氢化的机理。通过铱(I)/铱(III)机理进行的涉及通过两个分子内氢键稳定的过渡态的不对称氢化的计算光学收率与实验ee 值非常一致。