- Enantiodivergent Kinetic Resolution of 1,1′-Biaryl-2,2′-Diols and Amino Alcohols by Dipeptide-Phosphonium Salt Catalysis Inspired by the Atherton–Todd Reaction
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A highly enantiodivergent organocatalytic method is disclosed for the synthesis of atropisomeric biaryls via kinetic resolution inspired by a dipeptide-phosphonium salt-catalyzed Atherton–Todd (A-T) reaction. This flexible approach led to both R- and S-enantiomers by fine-tuning of bifunctional phosphonium with excellent selectivity factors (s) of up to 1057 and 525, respectively. The potential of newly synthesized O-phosphorylated biaryl diols was illustrated by the synthesis of axially chiral organophosphorus compounds. Mechanistic investigations suggest that the bifunctional phosphonium halide catalyst differentiates between the in-situ-generated P-species in the A-T process, mainly involving phosphoryl chloride and phosphoric anhydride, thus leading to highly enantiodivergent O-phosphorylation reactions. Furthermore hydrogen bonding interactions between the catalysts and phosphorus molecules were crucial in asymmetric induction.
- Chen, Yuan,Fang, Siqiang,Pan, Jianke,Ren, Xiaoyu,Tan, Jian-Ping,Wang, Tianli,Zhang, Hongkui
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supporting information
p. 14921 - 14930
(2021/05/10)
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- Copper-promoted oxidative-fluorination of arylphosphine under mild conditions
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An efficient method for the synthesis of phosphoric fluoride via oxidative coupling between hydrophosphine oxide and NaF is reported. DDQ serves as the oxidizing reagent as well as the hydrogen acceptor. The process involves a Cu(ii) catalysis and exhibits great functional group tolerance under mild reaction conditions. the Partner Organisations 2014.
- Liu, Na,Mao, Liu-Liang,Yang, Bin,Yang, Shang-Dong
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supporting information
p. 10879 - 10882
(2014/10/15)
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- New aspects connected with the synthesis of H-phosphinate anhydrides
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A novel reaction between sodium salt of phenylphosphinic acid PhP(O)(OH)H (1) and various phosphorus electrophiles, R2P(O)C1 (2; R = alkyl, aryl, alkoxy or aryloxy) has been described. The presented reaction showed a high selectivity (yield up to 96%) in the products of the symmetric phosphorus anhydrides, R2P(O)-O-(O)PR2(4), which preferentially come from the starting phosphorus electrophiles (2). The results demonstrate that the phosphorus-phosphorus mixed anhydrides, RPH(O)-O-(O)PR2(3) are unstable under basic condition and possibly decomposed with expulsion of a phosphinylidene (Ph-P=O) fragment (6).
- Nycz
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experimental part
p. 589 - 594
(2009/12/26)
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- Determination of water content in olive oil by 31P NMR spectroscopy
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A method for moisture determination in olive oil using 31P NMR spectroscopy is developed. This method is based on the replacement of the hydrogen atoms of water molecules with the tagging agents 2-chloro-4,4,5,5- tetramethyl-1,3,2-dioxaphospholane and diphenylphosphinic chloride. Both reagents were successful in determining moisture in olive oil. However, only the second reagent provided a clean and instantaneous reaction under mild condition with no side reactions as observed with the first reagent. A study comparison was made to assess the agreement between the present analytical NMR method and the well-established methods of Karl Fischer titration.
- Hatzakis, Emmanuel,Dais, Photis
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experimental part
p. 1866 - 1872
(2009/12/07)
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- Biomimetic building-up of the carbamic moiety: The intermediacy of carboxyphosphate analogues in the synthesis of N-aryl carbamate esters from arylamines and organic carbonates promoted by phosphorus acids
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The reaction of aromatic amines with dimethyl carbonate (DMC) or diphenyl carbonate (DPC) in the presence of organo-phosphorus acids [Ph2P(O)OH (1); (PhO)2P(O)OH (2); (BuO)2P(O)OH/(BuO)P(O)(OH)2 equimolar mixture (3)] affords carbamate esters, ArNHC(O)OR (R = Me, Ph) with high selectivity. The catalytic role played by the P-acid has been investigated and rationalized in terms of a reaction mechanism involving the intermediate formation of a carbonic-phosphinic(phosphoric) anhydride X2P(O)OC(O)OR (X = Ph, PhO; R = Me, Ph). The proposed mechanism shows intriguing analogies with the mechanism of formation of carbamate anion in living systems by carbamoyl phosphate synthetase (CPS) enzyme. Copyright
- Aresta, Michele,Berloco, Chlara,Quaranta, Eugenio
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p. 8073 - 8088
(2007/10/02)
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- THERMAL DISPROPORTIONATION OF DIPHENYLPHOSPHINE OXIDE AND 10H-PHENOXAPHOSPHINE 10-OXIDES
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Diphenylphosphine oxide at 175 deg and 0.1 torr for one hour produced diphenylphosphinic anhydride and diphenylphosphine along with a small amount of tetraphenyldiphosphine. 10H-Phenoxaphosphine 10-oxides reacted similarly under these conditions except that the product ratios varied with ring substitution. At 100 deg and 0.1 torr 2,8-difluoro-10H-phenoxaphosphine 10-oxide reacted differently than at 175 deg, producing the diphosphine monoxide at the lower temperature. The products were identified by 31P NMR spectroscopy.
- Levy, Jack B.,Hughes, Stefannie V.,Esancy, Michelle K.
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- (Diphenylphosphinoyl)oxyl: An Extremely Reactive Oxygen-Centered Radical
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The title radical, Ph2P(O)O., has been generated by laser flash photolysis (LFP) of the peroxide 2 (1) in CH3CN solution.It has a broad, structureless absorption extending from 400 to beyond 800 nm.Absolute bimolecular rate constants k for its reactions with various organic substrates have been measured by LFP.It has been found that Ph2P(O)O. is more reactive in hydrogen abstraction (e.g., cyclohexane, k= 2.4x1E8 M-1s-1) and addition (e.g., benzene, k= 9.1x1E8 M-1s-1) than any other organic oxygen-centered radical.Only HO. is (generally) more reactive.Although Ph2P(O)O. could not be directly detected by EPR spectroscopy , it was successfully spin-trapped with a nitrone and with alkenes and alkynes.The formation of Ph2P(O)O. in the photodecomposition but not in the thermal decomposition of 1 is supported by 31P NMR analyses of reaction products.Semiempirical AM1-PM3 calculations on H2P(O)O. are also reported.
- Korth, H.-G.,Lusztyk, J.,Ingold, K.U.
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p. 624 - 631
(2007/10/02)
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- A KINETIC STUDY OF PHOSPHINIC CARBOXYLIC MIXED ANHYDRIDES
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Using 32.4 MHz (31)P n.m.r. spectroscopy, disproportionation of a series of phosphinic carboxylic mixed anhydrides derived from protected α-amino acids has been studied both as a function of the substituents at phosphorus and structure of the α-amino acid being activated.It was found that the rates of disproportionation were insignificant from a preparative aspect compared with aminolysis at 0 deg C.
- Ramage, Robert,Atrash, Butrus,Hopton, David,Parrott, Maxwell J.
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p. 1617 - 1622
(2007/10/02)
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- The Behaviour of Oxalyl-bis(diphenylphosphane) Towards Oxygen
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In dependence of the solvent, oxalyl-bis(diphenylphosphane) (1) is oxidized with molecular oxygen either in a radical or an ionic mechanism to give - via the radicals PPh2 and the recombination products 2 (3) - the oxide 2 (4) and 2O (6), respectively.In both cases CO and CO2 are eliminated in nearly equal amounts. - Keywords: Oxidation of Oxalyl-bis(diphenylphosphane), Mechanism
- Lindner, Ekkehard,Kern, Herbert
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p. 790 - 792
(2007/10/02)
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- PHOSPHORORGANISCHE VERBINDUNGEN 93 Zur Chemie optisch aktiver Phosphinigsaereamide
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Optically active ethyl-phenyl-phosphinous acid diethylamide 1 was treated with HCl, HBF4, alcohols, thiols, carboxylic acids, esters, anhydrides, acid chloride, compounds with the structure element P-Cl and secondary phosphines to give in each case a racemic mixture of the corresponding, previously described, reaction products.Reaction of optically active 1 with para-cresol, para-cresyltrifluoro-acetate or 2,2,2-trifluoro-ethyl-trifluoro-acetate gives the corresponding optically active ester of ethyl phenyl phosphinous acid under retention of configuration.
- Horner, Leopold,Jordan, Manfred
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p. 235 - 242
(2007/10/02)
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