3220-50-6Relevant articles and documents
Wet and dry processes for the selective transformation of phosphonates to phosphonic acids catalyzed by br?nsted acids
Li, Chunya,Saga, Yuta,Onozawa, Shun-Ya,Kobayashi, Shu,Sato, Kazuhiko,Fukaya, Norihisa,Han, Li-Biao
, p. 14411 - 14419 (2020/12/29)
A "wet"process and two "dry"processes for converting phosphonate esters to phosphonic acids catalyzed by a Bronsted acid have been developed. Thus, in the presence of water, a range of alkyl-, alkenyl-, and aryl-substituted phosphonates can be generally hydrolyzed to the corresponding phosphonic acids in good yields catalyzed by trifluoromethyl sulfonic acid (TfOH) at 140 °C (the wet process). On the other hand, with specific substituents of the phosphonate esters, the conversion to the corresponding phosphonic acids can be achieved under milder conditions in the absence of water (the dry process). Thus, the conversion of dibenzyl phosphonates to the corresponding phosphonic acids took place smoothly at 80 °C in toluene or benzene in high yields. Moreover, selective conversion of benzyl phosphonates RP(O)(OR′)(OBn) to the corresponding mono phosphonic acids RP(O)(OR′)(OH) can also be achieved under the reaction conditions. The dealkylation via the generation of isobutene of ditert- butyl phosphonate, and the related catalysis by TfOH took place even at room temperature to give the corresponding phosphonic acids in good to high yields. Nafion also shows high catalytic activity for these reactions. By using Nafion as the catalyst, phosphonic acids could be easily prepared on a large scale via a simple process.
Rh(I)-catalyzed enantioselective hydrogenation of α-substituted ethenylphosphonic acids
Dong, Kaiwu,Wang, Zheng,Ding, Kuiling
supporting information; experimental part, p. 12474 - 12477 (2012/09/05)
A class of chiral Rh(I) catalysts containing monodentate phosphorous acid diesters tautomerized from the corresponding secondary phosphine oxides was discovered by serendipitous hydrolysis of phosphoramidite ligands. The evolved catalysts demonstrated unprecedented enantioselectivities (98-99% ee) and high catalytic activities (as low as 0.01 mol% catalyst loading) in asymmetric hydrogenations of a wide variety of α-aryl-/alkyl-substituted ethenylphosphonic acids, providing a facile approach to the corresponding enantiopure phosphonic acids with significant biological importance.
Synthesis of biologically active 1-arylethylphosphonates
Gulyukina,Dolgina,Bondarenko,Beletskaya,Bondarenko,Henry,Lavergne,Ratovelomanana-Vidal,Genet
, p. 573 - 587 (2007/10/03)
A convenient and inexpensive general preparation method for 1-arylethylphosphonic acids and their esters was developed involving in reduction of the corresponding 1-ethenylphosphonates by ammonium formate in the presence of palladium on carbon. A homogeneous enantioselective hydrogenation of 1-arylethenylphosphonic acids in the presence of chiral ruthenium catalysts provided optically active 1-arylethylphosphonic acids of enantiomeric purity up to 86%. The preliminary data on biological activity testing of the 1-arylethylphosphoic acids synthesized evidence that some among the compounds obtained are low-toxic substances with the properties of immunosuppressors of the central type of action.
