An enantiomerically pure P-stereo-genic bisphosphine: (S,S)-ethylene-bis[(2-methylphenyl)phenylphosphine] (o-tolyl-DiPAMP)

摘要

In connection with a research program involving the synthesis, structure determination, reactivity and ability to coordinate to metal centres of chiral bisphosphine ligands, we have synthesized and structurally characterized, by means of single-crystal X-ray diffraction analysis, the title compound {systematic name: (S,S)-(ethane-1,2-diyl)bis[(2-methylphenyl)-phenylphosphane], abbreviated as o-tolyl-DiPAMP}, C_(28)-H_(28)P_2. So far, neither the free bisphosphine (DiPAMP) nor analogues that incorporate the ethylenebisphosphine frame have had their crystal structures reported. The investigated compound forms crystals which are isostructural with the bisphosphine dioxide analogue [King et al. (2007). Acta Cryst. E63, o3278], despite the involvement of the dioxide in C-H...O(=P) hydrogen bonds and the lack of similar hydrogen bonds in the investigated crystal structure. In both molecules, the P-C-C-P chain is in a trans conformation, extended further at both ends by one of the two P-C_(ipso) bonds.