56763-64-5Relevant academic research and scientific papers
Nickel-catalysed conjugate addition to trimethylaluminum to sterically hindered α,β-unsaturated ketones
Flemming,Kabbara,Nickish,Neh,Westermann
, p. 317 - 320 (2007/10/02)
Nickel acetylacetonate is an efficient catalyst for the 1,4-addition of trimethylaluminum to α,β-unsaturated ketones. The reaction is strongly solvent dependent and gives best results in tetrahydrofuran or ethyl acetate. The reaction is especially useful for the nucleophilic 1,4-methyl transfer to sterically hindered enones. A β-cuparenone synthesis via conjugate methyl group addition to an enone precursor is described.
Copper-Catalyzed Conjugate Addition of Trimethylaluminium to α,β-Unsaturated Ketones
Kabbara, Jazid,Flemming, Steffen,Nickisch, Klaus,Neh, Harribert,Westermann, Juergen
, p. 1489 - 1494 (2007/10/02)
The conjugate methylation of α,β-unsaturated ketones with trimethylaluminium occurs smoothly in a very simple procedure under the catalytic CuI salts.Scope and limitations of this process as well as the influence of solvent and catalyst on the kinetics were studied.In addition, the effect of chlorotrimethylsilane as an additive was investigated.Attack on the carbonyl group in 1,2-fashion could not be observed under the reaction conditions.- Key Words: Conjugate alkylation / Trimethylaluminium / Copper catalysis
Photochemical Reactions. 137-th Communication. Preparation and Photolysis of (E/Z)-7-Methyl-β-ionone
Ishii, Keitaro,Mathies, Peter,Nishio, Takehiko,Wolf, Hans Richard,Frei, Bruno,Jeger, Oskar
, p. 1175 - 1183 (2007/10/02)
The title compounds (E/Z)-7 were prepared in 66percent overall yield by reaction of β-ionone ((E)-1) with lithium dimethylcuprate, trapping of the intermediate enolate with benzeneselenyl bromide and oxidation with H2O2.Analogously, (E/Z)-7-methyl-α-ionone ((E/Z)-12) was obtained in 65percent yield from α-ionone ((E)-11). 1n,?*-Excitation (λ > 347 nm, pentane) of (E)-7 causes rapid (E/Z)-isomerization and subsequent reaction of (Z)-7 to 15 (66percent).The formation of 15 is explained by twisting of the dienone chromofore due to repulsive interaction of the 7-CH3-group with the CH3-groups of the cyclohexene ring.On the other hand, irradiation, (λ > 347 nm, Et2O) of (E)-7 in the presence of acid leads to (Z)-7 (5percent) and to the novel compound 16 (88percent).
