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 {[(R)-(S)-Pigiphos]Rh(CH3CN)(3)}Y-3 (Y = PF6, (3a); OTf, (3b)) and {[(R)-(S)-Pigiphos]-Ni(CH3CN)}(BF4)(2) (4) containing the c hiral bis-fenocenyl triphosphine ligand (R)-(S)-Pigiphos have been synthesi zed and used as catalyst precursors for the acetalization of aldehydes and ketones with glycols. The reactions occur in mild conditions and require th e presence of molecular sieves as drying agent. The yields are generally ex cellent, but no significant diastereo- or enantioselectivity is observed. ( C) 1999 Elsevier Science B.V. All rights reserved.