Synthesis and Characterization of Chiral bis-Ferrocenyl Triphosphine Ni(II) and Rh(III) Complexes and their Use as Catalyst Precursors for Acetalization Reactions

The new metal complexes wR.-S.-PigiphosxRhCH3CN.34Y3 YsPF6, 3a.; OTf, 3b.. and wR.-S.-Pigiphosx- NiCH3CN.4BF4.2 4. containing the chiral bis-ferrocenyl triphosphine ligand R.-S.-Pigiphos have been synthesized and used as catalyst precursors for the acetalization of aldehydes and ketones with glycols. The reactions occur in mild conditions and require the presence of molecular sieves as drying agent. The yields are generally excellent, but no significant diastereo- or enantioselectivity is observed.