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.
作者:Hayashi, Tamio、Takahashi, Makoto、Takaya, Yoshiaki、Ogasawara, Masamichi、Durham, Timothy B.、Miller, J.
DOI:10.15227/orgsyn.079.0084
日期:——
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.
Rh-ImiFerroPhos complexes catalyzed asymmetric hydrogenation of β-substituted α,β-unsaturated hosphonates
A series of chiral ferrocenyl diphosphine ligands (ImiFerroPhos ligands) has been applied to the hydrogenation of beta-substituted alpha,beta-unsaturated phosphonates to generate a range of optically active beta-substituted alkylphosphonates in good yields with good enantioselectivity (up to 92% ee) under mild reaction conditions. (C) 2014, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.
Highly Enantioselective Rh-Catalyzed Hydrogenation of β,γ-Unsaturated Phosphonates with Chiral Ferrocene-Based Monophosphoramidite Ligands
An enantioselective synthesis of chiral alkylphosphonates bearing a beta-stereogenic center, based on the Rh-catalyzed asymmetric hydrogenation of corresponding beta-substituted beta,gamma-unsaturated phosphonates with a Ferrocene-based monophosphoramidite ligand Under the mild hydrogenation conditions, was developed, in which an ee value of up to 98% was obtained.