102808-70-8Relevant academic research and scientific papers
Resolutions involving metal complexation. Optical resolution and photochemical rearrangement of (±)-(2-mercaptoethyl)methylphenylphosphine
Leung, Pak Hing,Willis, Anthony C.,Wild, S. Bruce
, p. 1406 - 1410 (2008/10/08)
The asymmetric bidentate (±)-(2-mercaptoethyl)methylphenylphosphine has been resolved by the fractionial crystallization of a pair of diastereomeric thiolato-S-bridged dipalladium(II) complexes containing the deprotonated form of the ligand and ortho-metalated (R)-(1-(dimethylamino)ethyl)naphthalene. In order to recover the resolved ligand from the less soluble diastereomer of the dipalladium complex, the terminal palladium resolving unit was displaced with ethane-1,2-diamine, and the residual (thiolato)palladium(II) complex was treated with benzyl bromide; this gave a bromopalladium(II) complex containing (S)-(2-(benzylthio)ethyl)methylphenylphosphine bound through phosphorus only. The crystal and molecular structure of the bromopalladium complex has been determined. Crystal data: orthorhombic, P212121, a = 8.774 (1) A°, b = 17.908 (3) A°, c = 18.412 (4) A°, Z = 4, and R = 0.042. The geometry around the palladium is distorted square-planar with the tertiary phosphine-P stereocenter of S absolute configuration trans to the tertiary amine-N of the resolving ligand of R absolute configuration. Optically pure (R)-(2-(benzylthio)ethyl)methylphenylphosphine, [α]D -27.8° (c 1.6, dichloromethane), was displaced from the bromopalladium complex with (R*,R*)-(±)-1,2-phenylenebis(methylphenylphosphine) and was, in turn, converted by sodium in ammonia into a separable mixture of optically pure (R)-(2-mercaptoethyl)methylphenylphosphine, [α]D -17.0° (c 3.0, dichloromethane), and optically pure (R)-ethylmethylphenylphosphine, [α]D -7.3° (c 2.4, toluene). The (R)-(mercaptoethyl)phosphine rearranges in light with retention of configuration at phosphorus into optically pure (S)-ethylmethylphenylphosphine sulfide, [α]D -21.6° (c 2.0, methanol), by an intermolecular radical chain mechanism.
Optically Active Arsenic Macrocycles. Stereospecific Syntheses of Enantiomers and Diastereomers of 14-Membered trans As2S2 Chelating Macrocycles Containing Resolved Asymmetric Tertiary Arsine Donors
Kerr, Philip G.,Leung, Pak-Hing,Wild, S. Bruce
, p. 4321 - 4328 (2007/10/02)
The first optically active macrocycles containing arsenic, (R,R)- and (S,S)-1, have been synthesized by template dimerizations of the enantiomers of deprotonated (+/-)-(2-mercaptoethyl)methylarsine, (+/-)-3, on palladium(II) with
Resolutions involving metal complexation. Synthesis and resolution of (±)-(2-mercaptoethyl)methylphenylarsine. Crystal and molecular structure of (-)589-[Pd{(R)-CH3CH(1-C10H 6)NMe2-C2,N}{(S)-PhMeAsCH2CH 2S-As,μ-S}PdCl{(R)-CH3CH(1-C10H ...
Leung, Pak Hing,McLaughlin, George M.,Martin, John W. L.,Wild, S. Bruce
, p. 3392 - 3395 (2008/10/08)
Full title: Resolutions involving metal complexation. Synthesis and resolution of (±)-(2-mercaptoethyl)methylphenylarsine. Crystal and molecular structure of (-)589-[Pd{(R)-CH3CH(1-C10H 6)NMe2-C2,N}{(S)-PhMeAsCH2CH 2S-As,μ-S}PdCl{(R)-CH3CH(1-C10H 6)NMe2-C2,N}]·0.67CH2Cl 2. The asymmetric chelating agent (±)-(2-mercaptoethyl)methylphenylarsine has been resolved into its optical antipodes by the fractional crystallization of unusual μ-thiolato epimers containing two ortho-metalated [(R)-[1-(dimethylamino)ethyl]-naphthyl-C2,N]palladium(II) resolving units per bridging (methylphenylarsino)ethane-2-thiolato ligand. The least soluble epimer with [α]D -283° (CH2Cl2) crystallizes in the space group P212121, with a = 10.080 (2) A?, b = 14.157 (2) A?, c = 27.918 (4) A?, and Z = 4. The structure was solved by heavy-atom methods and refined by least-squares analysis to an R of 0.052 and Rw of 0.056 for 2347 reflections. The bridging thiolato atom and the coordinated arsenic atom both have the S absolute configuration in the dinuclear complex. Treatment of the dimer with diamino-1,2-ethane removes the terminal resolving unit and affords crystalline monomeric (-)589-[(R)-1-[1-(dimethylamino)ethyl]naphthyl-C 2,N][(S)-(methylphenylarsino)ethanethiolato-As,S]-palladium(II) from which optically pure (R)-(-)589-(2-mercaptoethyl)methylphenylarsine with [α]D -16.7° (CH2Cl2) was liberated by treatment with cyanide. The (S)-(+)589 enantiomer of the ligand was obtained in a state of 72% optical purity from the residual mixture of epimeric complexes and was subsequently brought to purity by fractional crystallization of the corresponding enantiomorphic dinuclear complexes containing (S)-dimethyl(1-(α-naphthyl)ethyl)amine.
