The axially dissymmetric diphosphines (-)-(R)-and (+)-(S)-(6,6'-dimethylbiphenyl-2,2'-diyl)bis(diphenylphosphine) ((-)-(R)-10 and (+)-(S)-10; 'BIPHEMP') have been synthesized, starting from (R)-and (S)-6,6'-dimethylbiphenyl-2.2'-diamine ((R)-and (S)-16), respectively, via Sundmeyer reaction, lithiation, and phosphinylation. Moreover, racemic 4,4'-dimethyl-and 4,4'-bis(dimethylamino)-substituted analogues 11 and 12, respectively, and the 6,6'-bridged analogue 1,l l-bis(diphenylphosphino)-5,7-dihydrodibenz[c, eloxepin (13) were synthesized and resolved into optically pure (R)-and (S)-enantiomers via complexation with di-p-chlorobis{. The molecular structures of the diphosphines (S)-10 and (R)-13 and of two derived cationic Rh (1) complexes, [Rh((S)-lO)(nbd)]BF, and [Rh((R)-13)(nbd)]BF4were determined by X-ray analyses. Absolute configurations were established for (+)-(S)-10 by X-ray analyses of both the free diphosphine and of the derived Rh(1) complex, and for (-)-(R)-l3 by X-ray analysis of the derived Rh(1) complex. Configurational assignments for the substituted BIPHEMP analogues 11 and 12 were achieved by means of 'H-NMR comparisons of the Pd(I1) complexes derived from the diphosphines and (R)-18, and by means of CD comparisons. The BIPHEMP ligand 10 and analogues 11, 12, and 13 are the first examples of optically active bis(triary1phosphines) containing the axially dissymmetric biphenyl moiety. All these new diphosphines proved to be excellent asymmetry-inducing ligands in Rh(1)-catalyzed isomerizations of N,N-diethylnerylamine affording citronella1 enamine of 98-99% ee.

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Bei der Reaktion von [C5H5CoCH3(CNCH3)PMe3]I (2) oder (3) mit Nitrilen RCN (R  CH3, C6H5, CH  CH2 CH  CHMe, CMe  CH2, c‐C3H5, NH2, NMe2, SMe) entstehen nahezu quantitative die Metalla‐Heterocyclen 4–12). Die Röntgenstrukturanalyse von 4a (R  CH3; X  I) beweist, daß der fünfgliedrige CoCNCN‐Heterocyclus völlig planar ist und auch die Kohlenstoffatome der Substituenten an C, N und C in der Ringebene liegen. Das Ring‐NCN‐Fragment ist aufgrund der Bindungslängen mit der N  C  N‐Gruppierung eines Amidins gut vergleichbar. Die Protonierung der Verbindungen 4–12 führt zu den [Amino(methyl)carben]cobalt(III)‐Komplexen (17–25), die mit NaOMe wieder zu 4–12 reagieren. Der acide Charakter der CoC(CH3)‐ und NH‐Protonen wird auch durch Deuterierungsexperimente belegt. Ausgehend von C5H5Co(CNCH3)PMe3/CH3CN/C 2C2H5I und C5H5Co(CNC6H5)PMe3/CH3 CN/CH3I wurden ebenfalls Metalla‐Heterocyclen mit den Ringbausteinen CoC(  CHCH3)N, CoC(C2H5)N, C(  CH2)N(C6H5)C und C(CH3)N(C6H5)C synthetisiert.