Optically active transition-metal complexes: Part 124. Chiral 1-phospha[1]ferrocenophanes and 1,12-diphospha[1.1]ferrocenophanes — synthesis, characterization and ring-opening polymerization

The phosphorus(III)-bridged [1]ferrocenophanes 1,1′-ferrocenediylphenylphosphine (1), (−)-1,1′-ferrocenediylmenthylphosphine (2) and (−)-bornyl-1,1′-ferrocenediylphosphine (3) have been synthesized via the reaction of 1,1′-dilithioferrocene (TMEDA adduct) and Cl2PR (R=Ph, Men, Bor). Compounds 1 and 2 have been used as ligands in the preparation of the complexes Cp*Mn(CO)2[Fe(η5-C5H4)2PPh] (4) and (−)-trans-PdCl2[Fe(η5-C5H4)2PMen]2 (5). The new compounds 2–5 were characterized by multinuclear NMR, by MS, and 2, 4 and 5 by single-crystal X-ray diffraction. Remarkably, the cyclic dimer anti-exo,exo-1,12-dimenthyl-1,12-diphospha[1.1]ferrocenophane (6) could be isolated and structurally characterized. The thermal ring-opening polymerization of 1, 2 and 3 yielded the poly(ferrocenediylphosphines) 7, 8 and 9. Compounds 2 and 8 were used as chiral ligands in the Rh-catalyzed diastereoselective hydrogenation of folic acid.