Enantioselective synthesis of optically active alkylphosphonates via Rh-catalyzed asymmetric hydrogenation of β-substituted α,β-unsaturated phosphonates
The Rh-catalyzed asymmetric hydrogenation of beta-substituted alpha,beta-unsaturated phosphonates using (S-c,S-p)-WalPhos as the chiral ligand is reported, in which a wide range of optically active beta-substituted alkylphosphonates were obtained in good yields and with good to excellent enantioselectivities (86-98% ee). In contrast to the Rh/(R-c,S-a)-FAPhos system previously reported by us, the present catalytic system shows a wider substrate scope, and can perform the hydrogenation under milder reaction conditions. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.
Cu-catalyzed asymmetric conjugate reduction of β-substituted α,β-unsaturated phosphonates: an efficient synthesis of optically active β-stereogenic alkylphosphonates
A series of chiral alkylphosphonates bearing beta-stereogenic center were synthesized in good enantioselectivities (up to 95% ee) via the CuH-catalyzed asymmetric conjugate reduction of beta-substituted alpha,beta-unsaturated phosphonates under optimal conditions using Cu(OAc)(2)center dot H2O as the copper source, (R)-SEGPHOS as the ligand. PMHS as the siloxane, and t-BuOH as the additive. (C) 2009 Elsevier Ltd. All rights reserved.
Inverting External Asymmetric Induction via Selective Energy Transfer Catalysis: A Strategy to β‐Chiral Phosphonate Antipodes
作者:Carina Onneken、Kathrin Bussmann、Ryan Gilmour
DOI:10.1002/anie.201911651
日期:2020.1.2
catalysts to the pro-chiral substrate. Although powerful, the strategy remains vulnerable to costs and availability of sourcing both catalyst enantiomers. Herein, a stereodivergent hydrogenation of α,β-unsaturated phosphonates is disclosed using a singleenantiomer of the catalyst. This enables generation of the R- or S-configured β-chiral phosphonate with equal and opposite selectivity. Enantiodivergence
Enantioselective Synthesis of Optically Active Alkanephos- phonates<i>via</i>Rhodium-Catalyzed Asymmetric Hydrogenation of β-Substituted α,β-Unsaturated Phosphonates with Ferrocene-Based Monophosphoramidite Ligands
series of chiral β-substituted alkanephosphonates was synthesized in high enantioselectivities via the first rhodium-catalyzedasymmetrichydrogenation of the corresponding β-substituted-α,β-unsaturated phosphonates using a ferrocene-derived monophosphoramidite ligand, with which up to 99.5% ee have been achieved for the hydrogenation of (E)-substrates and 98.0% ee for (Z)-substrates.