17045-47-5Relevant academic research and scientific papers
Scalable Enantiomeric Separation of Dialkyl-Arylphosphine Oxides Based on Host–Guest Complexation with TADDOL-Derivatives, and their Recovery
Bagi, Péter,Fogassy, Elemér,Herbay, Réka,Holczbauer, Tamás,Keglevich, Gy?rgy,Mátrav?lgyi, Béla,Madarász, János,Székely, Gy?rgy,Varga, Bence
supporting information, (2020/03/23)
Several dialkyl-arylphosphine oxides were prepared, and the enantioseparation of the corresponding racemates was elaborated with host–guest complexation using TADDOL-derivatives. The crystallization conditions were optimized and two separate crystallization methods, one in organic solvent, and the other in water, were found to yield five examples of phosphine oxides with enantiomeric excess values higher than 94 %. A gram scale resolution was performed, and both enantiomers of the methyl-phenyl-propyl-phosphine oxide were separated with (R,R)- or (S,S)-spiro-TADDOL. The intermolecular interactions responsible for the enantiomeric recognition between the chiral host and guest molecules were investigated by single-crystal X-ray diffractional structural determinations. The similarities in the structural patterns of a few diastereomeric crystals were checked by powder X-ray diffraction, as well. Organic solvent nanofiltration (OSN) was used as a scalable technique for the decomposition of the corresponding phosphine oxide–spiro-TADDOL molecular complexes, and for the recovery of the phosphine oxide enantiomers and resolving agents.
Stereoselective catalytic synthesis of P-stereogenic oxides via hydrogenative kinetic resolution
Fernández-Pérez, Héctor,Vidal-Ferran, Anton
supporting information, p. 7019 - 7023 (2019/09/30)
A highly stereoselective catalytic method for the preparation of structurally diverse P-stereogenic oxides has been developed. The approach relies on the ability of rhodium complexes derived from an enantiopure P-OP ligand to kinetically resolve racemic α,β-unsaturated phosphane oxides by hydrogenation of the C= C motif and formation of highly enantioenriched (or even enantiopure) P-stereogenic oxides. The practicality of the methodology has been demonstrated by the preparation of potentially functional P-chiral molecules for catalytic enantioselective synthesis.
Enantioselective preparation of P-chiral phosphine oxides
Adams, Harry,Collins, Rebecca C.,Jones, Simon,Warner, Christopher J. A.
, p. 6576 - 6579 (2012/01/15)
A highly efficient chiral auxiliary-based strategy for the asymmetric synthesis of P-chiral phosphine oxides in >98:2 er has been developed. The methodology involves the highly stereoselective formation of P-chiral oxazolidinones that then undergo displacement with a variety of Grignard reagents to prepare the desired phosphine oxides.
Synthesis of P-chiral, non-racemic phosphinylacetates via enzymatic resolution of racemates
Kielbasinski,Zurawinski,Pietrusiewicz,Zablocka,Mikolajczyk
, p. 564 - 572 (2007/10/03)
A series of racemic methyl phosphinylacetates was hydrolyzed in the presence of porcine liver esterase (PLE) under the kinetic resolution conditions to give the corresponding P-chiral phosphinylacetic acids and recovered esters in high enantiomeric purity (72-100% ee). The Jones' active site model was applied to explain the enantioselectivity of this reaction.
PHOSPHORORGANISCHE VERBINDUNGEN 92 Zur Stereochemie und zum chemischen Verhalten optisch aktiver Amidophosphoniumsalze und optisch aktiver Phosphinigsaereamide
Horner, Leopold,Jordan, Manfred
, p. 225 - 234 (2007/10/02)
Optically active amides of phosphinous acids R1R2PNR2 4 (R1 = Ph, R2 = Me, R = Et) may be obtained in high yield from the corresponding chiral amidophosphonium salts 1R2R3PNR2>X(R1 = Ph, R2 = CH3, Et, R3 = Bz or allyl, R = Et) via cathodic fassion or cyanolysis, both processes proceeding under retention of configuration at phosphorus.The optically active amidophosphonium salts (e.g. ethyl-methyl-phenyl-diethylamidophosphonium iodide 10 or benzyl-ethyl-phenyl-diethylamidophosphonium bromide 12 were prepared: a.) from the optically active tertiary phosphines (e.g.R-(+)-benzyl-methyl-phenyl-phosphine 6 or S-(-)-ethyl-methyl-phenyl-phosphine 13 on treatment with aryl or alkyl azides and subsequent alkylation of the ensueing phosphine imine 7. b.) from the chiral phosphinous acid amide 4 on alkylation.Methods a) and b) proceed under retention of configuration at phosphorus. c.) treatment of chiral phosphines with N-haloamines results in racemic amidophosphonium salts. Optically active amidophosphonium salts (eg.S-(+)-benzyl-methyl-phenyl-diethylamidophosphonium bromide 8 or R-(-) 10) are converted to the corresponding phosphine oxides 9 or 11 under inversion of configuration on treatment with aqueous alkali.LiAlH4 removes the amino ligand, converting amidophosphonium salts (eg.S-(+) 12) to the optically active phosphine under retention of configuration.Treatment of S(+)-ethyl-phenyl-diethylamidophosphonium bromide 5 with benzaldehyde gives stilbene and chiral ethyl-phenyl-phosphinic acid diethylamide 17 under retention of configuration; 7 is also obtained from R-(-) 4 on oxidation with H2O2.R-(-) 4 gives optically active ethyl-phenyl-thiophosphine acid diethylamide 18 on treatment with sulphur.Optically active 4 undergoes spontaneous racemization at 130 deg either in the neat phase or dissolved in hydrocarbons, zero order kinetics being observed.The racemization is proposed to occur through a cyclic bimolecular association, since compounds with different groups at phosphorus and nitrogen exchange ligands (forming crossed the phosphinous acid amides in approximately equal quantities) after three hours at 200 deg C.Phosphinous acid amides (eg. 4) form chiral charge-transfer complexes with nitrobenzene, which undergo racemization quickly even at room temperature.Optically active 4. when used as co-catalyst with (RhCl-hexa-1,5-diene), enables the homogeneous hydrogenation of α-ethylstyrene to 2-phenylbutane to be carried out with an optical yield of 34percent.
