SYNTHESIS OF ENDO,ENDO-2,5-BIS((DIPHENYLPHOSPHINO)METHYL)BI-CYCLO[2.2.1]HEPTANE, A CHELATING DIPHOSPHINE WITH A NATURAL BITE ANGLE OF 120-DEGREES

One of the key intermediates in rhodium-catalyzed hy-droformylation reactions is a trigonal-bipyramidal rhodium diphosphine species. The two phosphines in (R3P)2-(CO)2RhH have the possibility of occupying two axial, two equatorial, or one axial and one equatorial position. Use of chelating ligands such as DIPHOS, (C6H5)2PCH2CH2-P(C6H5)2, which has a preferred bite angle (P-M-P). © 1990, American Chemical Society. All rights reserved.