Kinetic resolution of the chiral iron acetyl complexes [Fe(CO) (η5-C5H5)(L)COCH3] [L= PPh 3, P(p-tolyl)3] via aldol reactions with camphor

Case-Green, Stephen C.; Costello, James F.; Davies, Stephen G.; Heaton, Nicholas; Hedgecock, Charles J. R.; Humphreys, Vanessa M.; Metzler, Michael R.; Primes, Jeremy C.

Abstract

The chiral iron acetyl complexes [Fe(CO)(η5-C 5H5)(L)COCH3] [L = PPh3, P(p-tolyl)3] have been kinetically resolved via aldol reactions involving their derived lithium enolates and camphor in the presence of lithium chloride. With (1R)-(+)-camphor the faster reacting iron acetyl enantiomer had the (S)-configuration allowing the (R)-iron acetyls to be obtained after recovery of starting material and crystallisation. The corresponding (S)-iron acetyls can be obtained by a base-promoted reverse aldol reaction of the isolated products. A mechanistic rationale for the high enantiomeric discrimination is proposed which involves a chelation-controlled chair transition state with a disfavourable 1 -methyl to cyclopentadienyl interaction in the mismatched pairing.

• Journal Article Type: Article
• Publication Date: Jan 1, 1994
• Journal: Journal of the Chemical Society, Perkin Transactions 1
• Print ISSN: 1472-7781
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Issue: 8, 1994
• Pages: 933-941
• DOI: https://doi.org/10.1039/P19940000933
• Keywords: kinetic, chiral iron acetyl, aldol reactions, camphor
• Public URL: https://uwe-repository.worktribe.com/output/1108694
• Publisher URL: http://dx.doi.org/10.1039/P19940000933