Herein, a synthesis of 2-phosphonodihydrofurans and 2-phosphonodihydropyrroles via 5-endo cyclization of O-and N-propargylated compounds is described. The reaction is promoted by potassiumtert-butoxide and allows a fast access to interesting heterocycles which were easily converted into 2-arylated pyrroles under acidic conditions.
Studies on Organophosphorus Compounds, 53: A New Procedure for the Synthesis of 1-Alkyl or 1-Aryl-1-hydroxy-2-nitroethylphoshonates under PTC Conditions
A series of dialkyl 1-alkyl- or 1-aryl-1-hydroxy-2-nitroethyl-phosphonates and 1-hydroxy-1-(nitromethyl)alkylphosphonates was prepared by nucleophilic addition of nitromethane to dialkyl acylphosphonates in the presence of potassium carbonate and tetrabutylammonium bromide.
Organocatalytic Highly Enantioselective Nitroaldol Reaction of α-Ketophosphonates and Nitromethane
作者:Tanmay Mandal、Sampak Samanta、Cong-Gui Zhao
DOI:10.1021/ol070209i
日期:2007.3.1
[reaction: see text] The first organocatalytichighlyenantioselective nitroaldol reaction of alpha-ketophosphonates and nitromethane has been realized by using cupreine (2) or 9-O-benzylcupreine (3) as the catalyst. Both catalysts are highly reactive and highlyenantioselective. alpha-Hydroxy-beta-nitrophosphonates have been synthesized in good yields and excellent enantioselectivities (>or=90% ee) at a low
The aldol reactions of α-keto phosphonates and aldehydes were facilitated by an axially chiral biphenylprolinamide under mild conditions, affording the synthetically and pharmaceutically useful products in high yields and excellent enantioselectivities.
Palladium-Catalyzed Asymmetric Hydrogenation of<i>N</i>-Hydroxy-α-imino Phosphonates Using Brønsted Acid as Activator: The First Catalytic Enantioselective Approach to Chiral<i>N</i>-Hydroxy-α-amino Phosphonates
作者:Nataliya S. Goulioukina、Ilya A. Shergold、Grigorii N. Bondarenko、Mikhail M. Ilyin、Vadim A. Davankov、Irina P. Beletskaya
DOI:10.1002/adsc.201200170
日期:2012.10.8
The enantioselective synthesis of ring-substituted [N-(hydroxy)amino](phenyl)methylphosphonic esters via asymmetric hydrogenation of the corresponding N-hydroxy-α-imino phosphonates with up to 90% ee was developed using catalytic amounts of palladium(II) acetate and (R)-BINAP in 2,2,2-trifluoroethanol with a Brønsted acid as an activator.