REACTIVITY OF TRICARBONYL(PENTADIENYL)IRON(1- PREPARATION OF AN OPTICALLY PURE TRICARBONYL(DIENE) IRON COMPLEX VIA 2ND-ORDER ASYMMETRIC TRANSFORMATION() CATIONS )

Reactions of tricarbonyl(2,4-dimethylpentadienyl)iron(1+) hexafluoroph osphate (1) with sodium methoxide/methanol and with phosphines are rep orted. Use of (S)-neomenthyldiphenylphosphine gives a 3:2 mixture of d iastereomers. Slow diffusion-controlled recrystallization of the mixtu re gives the single, optically pure diastereomer 6a in >80% mass recov ery via a second-order asymmetric transformation involving reversible addition of the phosphine. The stereochemistry of 6a at C2 (S) was det ermined by single-crystal X-ray diffraction analysis.