- 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
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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.
- Ibuka, Toshiro,Aoyagi, Takeshi,Yamamoto, Yoshinori
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p. 2417 - 2427
(2007/10/02)
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- DIFFERENCES IN THE REACTION OF ELECTRON DEFICIENT OLEFINS WITH ORGANOCOPPER(I)-LEWIS ACID REAGENTS AND EVIDENCE FOR A DIANIONIC EQUIVALENT
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Treatment of diethyl fumarate and triethoxycarbonylethylene with Bu2CuLi*AlCl3 led to 1,4-addition to give butylated products in high yields.In sharp contrast, diethyl meleate and tetraethoxycarbonylethylene predominantly gave the respective reduction products.The first evidence for a presumed dianionic intermediate by trapping with some electrophiles was also presented.
- Ibuka, Toshiro,Aoyagi, Takeshi,Kitada, Kazuko,Yoneda, Fumio,Yamamoto, Yoshinori
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p. C18 - C22
(2007/10/02)
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