Cp*RuOMe] 2 (1) reacts with phenols by successive exchange of one and two OMe groups for the phenolato group, forming mixed µ-methoxy-µ-phenolato complexes (5) and bis(µ-phenolato) dimeric complexes (6) successively. The latter, by an intramolecular rearrangement, convert into Cp*Ru(η 5 -oxocyclohexadienyl) complexes (7). With phenol and 2-methyl-5-isopropylphenol (carvacrol) the stepwise reactions were followed by NMR spectroscopy. Using 2,4-di-tert-butylphenol, both the mono(phenolato) (5c) and bis(phenolato) (6c) complexes have been isolated. The latter complex is obtained best from Cp*Ru(proline) (8) and 1. Complex 5c was characterized by an X-ray structure. The molecular geometry is very similar to the one found for 1. Organometallics 1996, 15, 3095-3098 S0276-7333(96)00121-5 CCC: $12.00

Reaction of [Cp*RuOMe]2 (1) with either enantiomer of the naturally occurring ketonic diterpene carvone or the trimethylsilyl enolate derived thereof leads to homochiral Cp*Ru−π-complexes 6−9, where the Cp*Ru moiety is bound to either the exocyclic double bond or an allyl function derived from it as well as to an enone or ene system in the ring. Full aromatization of the cyclic enone under the same reaction conditions was achieved with 7,8-dihydrocarvone or its trimethylsilyl enolate, respectively, giving complexes 13 and 14. The carvacrole complex 14 (and consequently also 13) is shown by the NMR spectra of the diasteroisomers obtained through derivatization with (S)-camphorsulfonic acid to be homochiral, thus, central chirality of the carvone has been fully transformed into planar chirality of the carvacrole complex. Compounds 6, 7·BF4, 7·CF3SO3, 8·CF3SO3, and 14·CF3SO3 where characterized by single-crystal X-ray analysis, which allowed for the determination of the absolute configuration of the latter.

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