Stereoselective oxidative addition of methyl iodide to chiral cyclometallated platinum(II) compounds derived from (R)-(+)-1-(1-naphthylethylamine). Crystal structure of [PtMe{3-(R)-(C10H7)CHMeNCHC4H2S}PPh3]

The reaction of 3-(R)-(C10H7)CHMeNCHC4H3S (2a) with [Pt2Me4(μ-SMe2)2] in acetone gave the new chiral cyclometallated platinum(II) compound [PtMe{3-(R)-(C10H7)CHMeNCHC4H2S}SMe2] (3a). Addition of PPh3 produced compound [PtMe{3-(R)-(C10H7)CHMeNCHC4H2S}PPh3] (4a) which was characterized by X-ray diffraction methods. While oxidative addition of methyl iodide to 3a gave two pairs of diastereomers, the analogous reaction for 4a produced only one diastereomer of the platinum(IV) compound [PtMe2I{3-(R)-(C10H7)CHMeNCHC4H2S}PPh3] (7a). Subsequent isomerization of the resulting platinum(IV) compound gave a new pair of diastereomers in relative amounts 90 and 10%. Analogous proportions of final diastereomers were obtained for the oxidative addition of methyl iodide to the new chiral compounds [PtMe{3-(R)-(C10H7)CHMeNCHAr}PPh3] (Ar=C6H4 (4b), 2-FC6H3 (4c), 2-CF3C6H3 (4d)). The reaction of [Pt2Me4(μ-SMe2)2] with imines (R)-(C10H7)CHMeNCH(2-BrC6H4) (2e) and (R)-(C10H7)CHMeNCH(2,6-Cl2C6H3) (2f) produced intramolecular oxidative addition to yield platinum(IV) compounds with some degree of stereoselectivity.