A Convenient (E)-Stereoselective Synthesis of Alkenylphosphonates
摘要:
Diethyl (E)-alkenylphosphonates have been prepared stereoselectively by dehydration of the corresponding beta-hydroxyphosphonates using DCC/CuCl2 in refluxing toluene. Starting beta-hydroxyphosphonates were obtained in high yield from diethyl methylphosphonate.
A Convenient (E)-Stereoselective Synthesis of Alkenylphosphonates
摘要:
Diethyl (E)-alkenylphosphonates have been prepared stereoselectively by dehydration of the corresponding beta-hydroxyphosphonates using DCC/CuCl2 in refluxing toluene. Starting beta-hydroxyphosphonates were obtained in high yield from diethyl methylphosphonate.
A new entry to β-hydroxyphosphonates: the SmI2-mediated reaction of diethyl iodomethylphosphonate with carbonyl compounds
作者:Fulvia Orsini、Alessandro Caselli
DOI:10.1016/s0040-4039(02)01539-3
日期:2002.9
In the presence of samarium iodide α-halophosphonates react with aliphatic carbonylcompounds (aldehydes and ketones) to afford β-hydroxyphosphonates in fairly good yields under neutral and mild conditions. Lower yields are obtained with aromatic carbonylcompounds.
The dynamic kinetic resolution (DKR) of racemic alpha-chloro beta-ketoesters and alpha-chloro beta-ketophosphonates through ruthenium-mediated asymmetric hydrogenation is reported. The corresponding alpha-chloro beta-hydroxyesters and alpha-chloro beta-hydroxyphosphonates were obtained in good to high enantio- and diastereomeric excesses using, in particular, the atropisomeric ligand DIFLUORPHOS. This methodology allowed an efficient preparation of the anti phenylisoserine side chain of Taxotere (R) which has been used for the hemisynthesis of the cancer therapeutic agent itself. In addition, C-13 NMR in chiral oriented solvents was used to investigate the DKR effect. (C) 2010 Elsevier Ltd. All rights reserved.
Reformatsky reactions with SmI2 in catalytic amount
作者:Fulvia Orsini、Elvira Maria Lucci
DOI:10.1016/j.tetlet.2005.01.079
日期:2005.3
A substoichiometric protocol for Reformatsky-type addition of alpha-haloesters, alpha-haloketones, alpha-halonitriles, and alpha-halophosphonates to carbonyl compounds has been developed. beta-Hydroxyesters and beta-hydroxynitriles were obtained in good to excellent yields. (C) 2005 Elsevier Ltd. All rights reserved.
A Convenient (E)-Stereoselective Synthesis of Alkenylphosphonates
Diethyl (E)-alkenylphosphonates have been prepared stereoselectively by dehydration of the corresponding beta-hydroxyphosphonates using DCC/CuCl2 in refluxing toluene. Starting beta-hydroxyphosphonates were obtained in high yield from diethyl methylphosphonate.