24766-10-7Relevant articles and documents
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.