SYNTHESIS, RESOLUTION AND REACTION OF (+/-)-1-(DIMETHYL-ARSINO)-2-(METHYLPHENYLPHOSPHINO)BENZENE - CRYSTAL AND MOLECULAR-STRUCTURE OF [(S), (S)]-(+)(589)-(2-[1-(DIMETHYL-AMINO)ETHYL]PHENYL-C-1, N)[1-(DIMETHYLARSINO)-2-(METHYL-PHENYLPHOSPHINO)BENZENE-AS,P]PALLADIUM(II) HEXAFLUOROPHOSPHATE

Asymmetric bidentate (+/-)-1-(dimethylarsino)-2-(methylphenylphosphino)benzene has been prepared by the reaction of sodium dimethylarsenide with (+/-)-1-chloro-2-(methylphenylphosphino)benzene in tetrahydrofuran. Its resolution has been achieved by the separation by fractional crystallisation of a pair of internally diastereomeric palladium(II) complexes containing the racemic ligand and orthometallated (S)-dimethyl(1-phenylethyl)amine. The optically pure antipodes have alpha +/- 32 degrees (589 nm, dichloromethane). The absolute configuration of the R enantiomer of the ligand has been assigned by a crystal-structure determination of the least-soluble diastereomeric complex [(S),(S)]-(+)(589)-{2-[1-(dimethylamino)ethyl]pheny]-C-1,N}[1-(dimethylarsino)-2-(methylphenylphosphino)benzene-As,P] palladium (II) hexafluorophosphate. Chemoselective cleavage of the dimethylarsino moiety of the free benzene derivative occurs in the presence of lithium metal in tetrahydrofuran.