New 1,1 '- or 1,2- or 1,3-bis(diphenylphosphino)ferrocenes

The syntheses of ferrocenyl phosphines with bulky substituents are reported using the reaction between FeCl2 and the suitably substituted cyclopentadi enyl salts, LiC5H3-1,3-(PPh2)(2), LiC5H3-1-PPh2-3-Bu-t, LiC5H2-1,2-(PPh2)(2 )-4-Bu-t. This strategy leads to bi-, tri- and tetraphosphines, which canno t be obtained by the other access paths used to prepare substituted ferroce nes. [C5H3-1,3(PPh2)(2)](C5H5)Fe, [C5H3-1-PPh2-3-Bu-t](2)Fe racemic and mes o and [C5H2-1,2-(PPh2)(2)-4-Bu-t](C5H5)Fe have been characterized by single -crystal X-ray diffraction studies. (C) 2000 Elsevier Science S.A. All righ ts reserved.