1.5- Diketone synthesis

Conjugate addition to nitro-olefins—1,4-diketone synthesis... 

It is well known that ir-allylpalladium complexes (86) are easily formed by the reaction of PdCb with P. y-unsaturated esters or ketones (85). An attempted oxidation of. y-unsaturated esters and ketones with the PdCl2/CuCl/02 catalyst system in aqueous DMF led to ir-allylpalladium complex formation as the main reaction, and the oxidation of the alkenic bond was hardly observed to a significant extent. However, in aqueous dioxane or THF, the oxidation became the main reaction, giving y-keto esters and 1,4-diketones (87), respectively, with high regioselectivity (Scheme 26).Some results are shown in Table 2. In all cases, no P-keto ester or 1,3-diketone was detected. At the end of the reaction, formation of a considerable amount of the ir-allylpalladium complex (86) was observed. y-Keto esters and 1,4-diketones are useful intermediates for Ae preparation of cyclopentanedione and cyclopentenone, respectively, by base-catalyzed cyclization. Tliis regioselective oxidation provides a unique and efficient synthetic method for y-keto ester and 1,4-diketone synthesis. 

Figure 2.36 Molecular structure of [Gd(L )3(H20)]-4H20 co showing 30% ellipsoids with all H atoms and lattice solvent molecules removed [43]. (Reproduced with permission from RC. Andrews, G.B. Deacon, R. Frank, B.H. Fraser, P.C. Junk, et al., Formation of Ho trinuclear clusters and Gd monodimensional polymers induced by ortho and para regioisomers of pyridyl-functionahsed fi-diketones synthesis, structure, and magnetic properties, European Journal of Inorganic Chemistry, 2009, 6, 744-751. Wiley-VCH Verlag GmbH Co. KGaA.)...

Andrews, P.C., Deacon, G.B., Frank, R., et al. (2009) Formation of Ho trinuclear clusters and Gd monodimensional polymers induced by ortho and para regioisomers of pyridyl-functionalised P-diketones synthesis, structure, and magnetic properties. European Journal of Inorganic Chemistry, 744-751. 

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