241496-50-4Relevant articles and documents
The Synthesis of α-Aminophosphonates via Enantioselective Organocatalytic Reaction of 1-(N-Acylamino)alkylphosphonium Salts with Dimethyl Phosphite
Ku?nik, Anna,Pa?dzierniok-Holewa, Agnieszka,Stecko, Sebastian,Wal?cka-Kurczyk, Alicja,Walczak, Krzysztof
, (2020/01/28)
α-Aminophosphonic acids are phosphorus analogues of α-amino acids. Compounds of this type find numerous applications in medicine and crop protection due to their unique biological activities. A crucial factor in these activities is the configuration of the stereoisomers. Only a few methods of stereoselective transformation of α-amino acids into their phosphorus analogues are known so far and all of them are based on asymmetric induction, thus involving the use of a chiral substrate. In contrast, we have focused our efforts on the development of an effective method for this type of transformation using a racemic mixture of starting N-protected α-amino acids and a chiral catalyst. Herein, a simple and efficient stereoselective organocatalytic α-amidoalkylation of dimethyl phosphite by 1-(N-acylamino)alkyltriphenylphosphonium salts to enantiomerically enriched α-aminophosphonates is reported. Using 5 mol% of chiral quinine- or hydroquinine-derived quaternary ammonium salts provides final products in very good yields up to 98% and with up to 92% ee. The starting phosphonium salts were easily obtained from α-amino acid derivatives by decarboxylative methoxylation and subsequent substitution with triphenylphosphonium tetrafluoroborate. The appropriate self-disproportionation of enantiomers (SDE) test for selected α-aminophosphonate derivatives via achiral flash chromatography was performed to confirm the reliability of the enantioselectivity results that were obtained.
Asymmetric hydrogenation of α- And β-enamido phosphonates: Rhodium(I)/monodentate phosphoramidite catalyst
Zhang, Jinzhu,Li, Yang,Wang, Zheng,Ding, Kuiling
supporting information; experimental part, p. 11743 - 11747 (2012/01/03)
High efficiency and enantioselectivity have been achieved in the Rh I-catalyzed asymmetric hydrogenation of α- and β-enamido phosphonates using a monophosphoramidite as the chiral ligand (see scheme; cod=1,5-cyclooctadiene), thus affording the optically active amino phosphonates with a turnover frequency of up to 1800 h-1 and high ee values. Copyright
Readily available chiral phosphine-aminophosphine ligands for highly efficient Rh-catalyzed asymmetric hydrogenation of α-enol ester phosphonates and α-enamido phosphonates
Wang, Dao-Yong,Huang, Jia-Di,Hu, Xiang-Ping,Deng, Jun,Yu, Sai-Bo,Duan, Zheng-Chao,Zheng, Zhuo
, p. 2011 - 2014 (2008/09/20)
(Chemical Equation Presented) A new class of unsymmetrical hybrid phosphine-aminophosphine ligands has been prepared from commercially available, inexpensive (S)-1-phenylethylamine through a concise synthetic procedure. These ligands are not very sensitive to air and moisture, and displayed good enantioselectivities in the Rh-catalyzed asymmetric hydrogenation of various dimethyl α-benzoyloxyethenephosphonates bearing β-aryl, β-alkyl, and β-alkoxy substituents and N-benzyloxycarbonyl α-enamido phosphonates, in which up to 97% ee was obtained. A side-by-side comparison study disclosed that these new phosphine-aminophosphine ligands showed better enantioselectivity than BoPhoz ligands.
