Asymmetric Hydroformylation Catalyzed by Homogeneous and Polymer-Supported Platinum Complexes Containing Chiral Phosphine Ligands

Article abstract of DOI:10.1021/ja00257a036

A complex of Pt(II) containing the chiral ligand (2S,4S)-N-(tert-butoxycarbonyl)-4-(diphenylphosphino)-2-<(diphenylphosphino)methyl>pirrolidine <(-)-BPPM> in the presence of stannous chloride catalyzed the hydroformylation of a variety of prochiral olefins.Although the branched/normal (b/n) ratios were low (ca. 0.5), high ee's were achieved in the hydroformylation of styrene (70-80percent), p-isobutylstyrene (80percent), 2-vinylnaphthalene (77percent), 2-ethenyl-6-methoxynaphthalene (81percent), 4-(2-thienylcarbonyl)styrene (78percent), vinyl acetate(82percent), N-vinylphthalimide (73percent), methyl methacrylate (60percent), and norbornene (60percent).When the hydroformylation of styrene, 2-ethenyl-6-methoxynaphthalene, and vinyl acetate with <(-)-BPPM>PtCl2/SnCl2 was carried out in the presence of triethyl orthoformate, enantiomerically pure acetals were obtained.The hydroformylation in the presence of ethyl orthoformate also could be carried out by using a catalyst containing the <(-)-BPPM>PtCl2/SnCl2 complex bound to 60-μm beads composed of cross-linked polystyrene.