We report herein the asymmetric synthesis of C-2-symmetric fused diferrocen
yl diamine and diol ligands. The synthesis begins with the Cu(II)-mediated
coupling of the diastereomerically and enantiomerically pure lithiated deri
vative of Kagan's ferrocenyl acetal to yield, after deprotection, the C-2-s
ymmetric biferrocenyl dialdehyde 4. Conversion of dial 4 to a bis(methylimi
ne) followed by a SmI2 mediated aza-pinacol coupling, yielded the enantio-
and diastereomerically pure C-2-symmetric trans-diamine 1. The direct pinac
ol coupling of dialdehyde 4 by SmI2 yields the enantio- and diastereomerica
lly pure C-2-symmetric trans-diol 2. The former diamine was coordinated to
the Lewis acid (ArO)(2)TiCl2 (Ar = 4-vinyl-2,6-dimethylphenyl) and characte
rized by solution and X-ray methods. The diol ligand was reacted with (dppe
)Pt(CO3) to form a (dppe)Pt-II diolate, which was also characterized by sol
ution and solid-state means.