PH-functional phosphines with 1,1 '-biphenyl-2,2 '-bis(methylene) and 1,1 '-binaphthyl-2,2 '-bis(methylene) backbones

The first PH-functional phosphines (1, 3, and 5) containing the 1,1'-binaph thyl-2,2'-bis(methylene) or 1,1'-biphenyl-2,2'-bis(methylene) backbone have been obtained by two-phase phosphination of 2,2'-bis(halomethyl)-1,1'-bina phthyls with PH3 or in a protected-group synthesis using P(SiMe3)(3) as the starting material. The 4,5-dihydro-3H-dinaphtho[2,1-c:1',2'-e]phosphepine (1) is configurationally stable, as indicated by the inequivalence of the t wo CH2 and naphthyl substituents in the C-13{H-1} NMR spectra. The X-ray cr ystal structure of 1.0.5C(6)H(5)CH(3) shows an intracyclic C-P-C angle of 9 9.5(2)degrees, the interplanar angle of the phosphepine ring system being 6 7.6(5)degrees. The borane adduct 7 of the secondary phosphine 1 has been em ployed for the syntheses of atropisomeric mono- and bidentate ligands (8-14 ) with the bulky 1,1'-binaphthyl moieties. Results of force field calculati ons on the conformations of 1, 3, and 14 are presented. The ability of thes e phosphines to form mononuclear and polynuclear complexes with transition- metal centers is discussed. Compound 14 exhibits a large variety of low-ene rgy conformations, and some of them seem to be capable of forming mononucle ar transition-metal complexes.