73934-61-9Relevant academic research and scientific papers
Reduction-alkylation with organocopper(I) reagents-alkyl halydes: Highly regioselective α-alkylation of γ-acetoxy-α,β-enoates with lithium dibutylcuprate-alkyl halides and difference in the reactivity of electron-deficient olefins with organocopper(I)-Lewis acid reagents
Ibuka, Toshiro,Aoyagi, Takeshi,Yamamoto, Yoshinori
, p. 2417 - 2427 (2007/10/02)
Reaction of γ-acetoxy-α,β-enoates with lithium dialkylcuprate followed by alkyl halides results in the predominant or exclusive formation of α-alkyl-β,γ-enoates in high yields under mild conditions, and a synthetic application to (+-)-α-vetispirene is presented.Treatment of diethyl fumarate and triethoxycarbonylethylene with Bu2CuLi*AlCl3 led to 1,4-addition to give conjugate adducts in high yields.In sharp contrast, diethyl maleate and tetraethoxycarbonylethylene predominantly gave the respective reduction products.Evidence for a presumed dianionic intermediate, based on trapping with some electrophyles, is also presented.Keywords - γ-oxygenated α,β-enoate; β,γ-enoate; deconjugative reduction; α-vetispirene; lithium dialkylcuprate; organocopper(I)-Lewis acid.
Highly Regioselective α-Alkylation of γ-Acetoxy-α,β-enoates by Reduction-Alkylation with Lithium Dibutylcuprate-Alkyl Halide: Application to the Synthesis of Spirovetivanes
Ibuka, Toshiro,Aoyagi, Takeshi,Yoneda, Fumio
, p. 1452 - 1454 (2007/10/02)
Reaction of γ-acetoxy-α,β-enoates with lithium dibutylcuprate followed by alkyl halides results in the predominant or exclusive formation of α-alkyl-β,γ-enoates in high yields under mild conditions; a synthetic route to (+/-)-α-vetispirene is also present
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
Yamamoto, Yoshinori,Yamamoto, Sinichi,Yatagai, Hidetaka,Ishihara, Yuji,Maruyama, Kazuhiro
, p. 119 - 126 (2007/10/02)
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.
