The synthesis of endo-3-diphenylphosphino-(1 R)-(+)-camphor (L) and some of its complexes with palladium(II), platinum(II) and rhodium(I); crystal structures of L and cis-[PdCl 2L 2

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Treatment of (1 R)-(+)-camphor with LiBu n, followed by Ph 2PCl gives, as the main product, exo-3-diphenylphosphino- (1 R)-(+)-camphor ( 3a) together with some of the corresponding enolate anion 1. However, on storage the exo- phosphine 3a isomerises to the corresponding endo-phosphine 3b which becomes the main product and was isolated in 70% yield. The crystal structure of 3b was determined and detailed 13C and proton NMR data are given. In chloroform solution, in the presence of acetic acid as catalyst, the endo-phosphine 3b is partially converted back into the exo-isomer 3a over 2 days. The endo-phosphine 3b (L) with H 2O 2 gives the corresponding phosphine oxide 3c and with monoclinic sulfur the corresponding phosphine sulfide 3d. With [PdCl 2(NCPh) 2] the endo-phosphine 3b gives [PdCl 2L 2] which exists as a cis-trans mixture 4a and 4b in solution. We have determined the X-ray crystal structure of the cis-form 4b. Treatment of [PtCl 2(COD)] with L, gives cis-[PtCl 2L 2] ( 4c) but with [PtCl 2(NCMe) 2] the corresponding trans complex trans-[PtCl 2L 2] ( 4d) is formed. In compounds 4a-4d the PPh 2 groups are endo. The complexes of type [MCl 2L 2] (MPd or Pt) are also formed by treating the bis-camphorphosphine enolates [M(PPh 2C 10H 14O) 2] with HCl. The complexes of type cis-[Pt(CCR) 2(PPh 2C 10H 15O) 2] (RPh or C(Me)CH 2) with HCl give exclusively cis-[PtCl 2L 2]. Treatment of [Rh 2Cl 2(CO) 4] with the endo-phosphine 3b (L) gives trans-[RhCl(CO)L 2]. 1H, 31P and some 13C data are given. Crystals of endo-3-diphenylphosphino-(1 R)-(+)-camphor ( 3b) are orthorhombic, space group P2 12 12 1 with a=778.6(1), b=1138.8(1), c=2128.9(3) pm and Z=4, R=0.0329 for 1674 observed reflections. The structure shows that the PPh 2 is endo. Crystals of 4b are orthorhombic, space group P2 12 12 1, with a=1380.3(2), b=1785.1(3), c=1922.8(4) pm and Z=4, R=0.0425 for 4438 observed reflections. The structure shows that the PPh 2 groups are endo and that the phosphines are cis.