- Copper-Catalyzed Conjugate Addition of Trimethylaluminium to α,β-Unsaturated Ketones
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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
- Kabbara, Jazid,Flemming, Steffen,Nickisch, Klaus,Neh, Harribert,Westermann, Juergen
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p. 1489 - 1494
(2007/10/02)
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- Lewis Acid Mediated Reactions of Organocopper Reagents. Entrainment in the Conjugate Addition to α,β-Unsaturated Ketones, Esters, and Acids via the RCu*BF3 System
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Lewis acid mediated reactions of organocopper reagents with various kinds of α,β-unsaturated carbonyl derivatives are described.RCu*BF3, as well as RCu-other Lewis acid systems, is useful for the conjugate addition to the α,β-unsaturated ketones and esters, whose double bonds are sterically crowded.Certain α,β-unsaturated carboxylic acids also undergo a 1,4-addition through this reagent.Methyl sorbate undergos a 1,4-addition via BuCu*BF3, while undergoing a 1,6-α,δ-addition via Bu2CuLi.BuCu*BF3 reacts more readily with an aldehyde than with a ketone; the degree of chemoselectivity is greater than that of Bu2CuLi, BuLi, or BuMgBr.The R2CuLi-BF3 system is useful for the double alkylation of α,β-unsaturated esters at the β-position and the carbonyl center.Stereochemical aspects of these new copper reagents are also reported.
- Yamamoto, Yoshinori,Yamamoto, Sinichi,Yatagai, Hidetaka,Ishihara, Yuji,Maruyama, Kazuhiro
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p. 119 - 126
(2007/10/02)
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