Organolithium reagents, reaction with diketones

The synthesis of 1,5-diketones 521 from 3,4-dihydropyranones 519 has been reported and is shown in Scheme 95 <1999T9333>. Organolithium reagents were used to open the lactone reagents, and best results were achieved when the reactions were quenched with trimethylsilyl chloride prior to hydrolytic workup. 

Tricarbonyliron complexes of enones.1 Reaction of Fe2(CO), with a,f -enones in toluene at 70-75° results in tricarbonyliron complexes, which on reaction with Grignard reagents, organolithium, or organocuprates are converted into 1,4-diketones. 

Enone Complexation. Various a,p-unsaturated ketones form moderately stable tricarbonyliron complexes (18), and offer access to 1,4-diketones (19) by reaction with Grignard reagents, organolithium reagents (eq 14), or organocuprates. Trimethylsilyloxybutadienes require phenyl substituents to form stable complexes by reaction with Fc2(CO)9. Enone complexes are also useful as transfer reagents to place Fe(CO)3 on diene ligands. A related procedure employs complexes of a,3-unsaturated imines in the same way. ... 

MetalIa-/3-diketonate complexes, such as 1, are conveniently prepared by reacting acylmetal carbonyl complexes with strong bases that can also react as nucleophiles, such as organolithium, Grignard, or boron hydride reagents [Eq. (1)]. These reactions can be followed by IR spectroscopy. 

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