Unexpected Rearrangement of Diethyl (±)(S,S)-1,2-epoxy-2-Phenylpentylphosphonate by NH 3(aqu.) : An Easy Entry to Ethyl 1-Formyl-1-Phenylbutylphosphonate
摘要:
A simple reaction of diethyl (+/-)(SS)-1,2-epoxy-2-phenylpentylphosphonate with 28% NH3(aqu.) in MeOH led to the ethyl 1-formyl-1-phenylbutylphosphonate in excellent yield. The procedure consists simply in stirring the substrate and 28% NH3(aqu.) in MeOH, at 40degreesC.
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.
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.
A convenient stereoselective synthesis of disubstituted alk-1-enyl phosphonates
A stereoselective synthesis of disubstituted diethyl alk-1-enylphosphonates has been developed via syn addition of RMgX/CuCl to alk-1-inylphosphonates.
Dioxirane oxidation of substituted vinylphosphonates: a novel efficient route to 1,2-epoxyalkylphosphonates
A new stereoselective route to substituted 1,2-epoxyalkylphosphonates through oxidation of corresponding alk-1-enylphosphonates by 'in situ' generated ethylmethyldioxirane is described. (C) 1998 Elsevier Science S.A. All rights reserved.