D. Bhaduri et al., SYNTHESES AND REACTIONS OF IRON AND RUTHENIUM COMPLEXES OF AN OPTICALLY PURE FUSED CYCLOPENTADIENYL LIGAND, Organometallics, 13(6), 1994, pp. 2291-2298
Optically pure )-9,9-dimethyltricyClo[6.1.1.0(2,6)]deca-2,5-diene (HPC
p) reacts with Fe-(CO)5 and Ru3(CO)12, in the presence of the hydrogen
acceptor norbornene, to form the isomorphic and isostructural complex
es Cis-[PCPM(CO)2]2 (M = Fe (t), Ru (8)), in which the metal is coordi
nated exclusively to the exo face of PCp. These complexes react with i
odine to form PCPM(CO)2I (M = Fe(2), Ru(9)) Complex 2 reacts with 1-ph
enyl-3,4-dimethylphosphole (DMPP), diphenylvinylphosphine (DPVP), and
phenyldivinylphosphine (DVPP) to form two diastereomers of PCpFe(CO)(D
MPP)l (3a,b), PCpFe(CO)(DPVP)I, (4a,b), and PCpFe(CO)-(DVPP)I (5a,b),
respectively. Complex 9 reacts with DMPP to form two diastereomers of
PCpRu(CO)(DMPP)l (10a,b). Complexes 4a and 4b react with DPVP and DVPP
to undergo sequential ligand substitution and intramolecular [4 + 2]
Diels-Alder cycloaddition forming four and five diastereomers of [PCpF
e(CO)(DMPP)(DPVP)]I (6a-d) and [PCpFe(CO)(DMPP)-(DVPP)]I (7a-e), respe
ctively. Complexes 10a and 10b similarly react with DPVP and AgBF4 to
form four diastereomers of the [4 + 2] Diels-Alder adducts [PCpRu(CO)(
DMPP)(DPVP)] BF4 (11a-d). Little asymmetric induction is observed in t
hese metal-promoted intramolecular [4 + 2] Diels-Alder cycloadditions.
New complexes were characterized by elemental analyses, infrared spec
troscopy, and H-1, C-13{H-1}, and where appropriate P-31{H-1} NMR spec
troscopy. The structures of 8 and 9 were confirmed by X-ray crystallog
raphy. Both compounds crystallized in the acentric space group P2(1)2(
1)2, in unit cells with the following dimensions. 8: a = 12.082(2) ang
strom, b = 18.689(5) angstrom, c = 11.156(2) angstrom, V = 2519.o(9) a
ngstrom3, Z = 4. 9: a = 20.061(5) angstrom, b = 7.166(2) angstrom, c =
10.323(2) angstrom, v = 1483.9(6) angstrom3, Z = 4. Refinements conve
rged to R(F) = 0.054 and 0.045 for 3561 and 2185 independent observed
(I > 4sigma(I)) reflections. In both compounds ruthenium coordinates t
o the less sterically hindered exo face of the PCp ligand, anti to the
gem-dimethyl groups.