Diketones reaction with organolithium

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. 

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. 

An acyl group can be introduced into the 4 position of an a,(3-unsamrated ketone by treatment with an organolithium compound and nickel carbonyl. The product is a 1,4-diketone, 157. The R group may be aryl or primary alkyl. The reaction can also be applied to alkynes (which need not be activated), in which case 2 mol add and the product is also a 1,4-diketone (e.g., R C=CH RCOCHR CH2COR). " In a different procedure, ot,(3-unsaturated ketones and aldehydes are acylated by treatment at — 110°C with R2(CN)CuLi2 and CO. This method is successful for R = primary, secondary, and tertiary alkyl.For secondary and tertiary groups, R(CN)CuLi (which does not waste an R group) can be used instead. 

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