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Theorthometalated [1-(dimethylamino)ethyl]naphthalene platinum(II) complexhas been used successfully to promote the asymmetric cycloadditionreaction between 3,4-dimethyl-1-phenylphosphole and sulfoxide in highselectivity. The exo-cycloadduct coordinated to theplatinum template as bidentate chelates via their phosphorus and sulfuratoms. The dichloro platinum complexes could be crystallized and werestable in the solid state as well as in solution. Optically pure P–Sbidentate ligands could be liberated from these dichloro complexesby treatment with aqueous potassium cyanide. The study also highlightsthe difference in reactivity and mode of substrate activation betweenan earlier study involving a Pd analogue of the template and the currentresults. [ABSTRACT FROM AUTHOR]

The organopalladium complex containing ortho-metalated (S)-[1-(dimethylamino)ethyl]naphthalene as the chiral auxiliary has been used successfully to promote the asymmetric cycloaddition reaction between 3,4-dimethyl-1-phenylarsole and diphenylvinylphosphine oxide in high stereoselectivity (only one isomer). However, the neutral dichloro palladium complex obtained upon removal of the auxiliary is very unstable and instantly decomposed to produce the arsenic elimination reaction product (3,4-dimethyl-2,4-cyclohexadienyl)diphenylphosphine oxide. However when the same reaction was promoted by the analogous platinum complex, only one stereoisomer was again obtained, but the resulting dichloro platinum complex is very stable in the solid state as well as in solution and coordinates to the platinum center as a As−O bidentate ligand, as confirmed by 1H NMR and single-crystal X-ray analysis. The enantiomerically pure As ͡PO hetero-bidentate ligand could be readily liberated from the dichloro platinum complex as an air-sensitive solid by treatment of the complex with aqueous potassium cyanide. [ABSTRACT FROM AUTHOR]

The organopalladium complex containing ortho-metalated (S)-[1-(dimethylamino)ethyl]phenylene as the chiral auxiliary has been used as the chiral template to promote the asymmetric cycloaddition reaction between diphenylvinyiphos- phine and 3,4-dimethyl-1-phenylarsole. A diphenylphosphino-substituted asymmetrical heterobidentate arsanorbornene (As-P) ligand was obtained stereoselectively on the chiral palladium template in moderate yield. The chiral benzylamine auxiliary could be removed chemoselectively from the template by treatment with HCl to produce the neutral complex [(As-P)PdCl2]. In contrast to their reported P-P analogue, the arsenic donor in the dichloro complex could be eliminated stereospecifically under mild reaction conditions to generate the corresponding 1-(diphe- nylphosphino)-3,4-dimethyl-2,4-cyclohexadiene, which remained as a bidentate ligand at the PdCl2 unit via phosphorus and the η²-C4-C5 double bond. The arsenic-elimination process was found to be influenced by the halo ligand in [(As-P)PdX2]. A similar process was observed with the analogous dibromo complex, but the corresponding diiodo species did not show similar reactivity. All of the novel As-Pd complexes have been characterized by X-ray crystallography. [ABSTRACT FROM AUTHOR]