Asymmetric Dihydroxylation of β,γ-Unsaturated Carboxylic Esterswith Trisubstituted C=C Bonds – Enantioselective Syntheses of Trisubstituted γ-Butyrolactones
作者:Tobias Kapferer、Reinhard Brückner
DOI:10.1002/ejoc.200500963
日期:2006.5
β,γ-Unsaturated esters with stereodefined trisubstitued C=C double bonds were prepared by the Arndt–Eistert homologation of α,β-unsaturated carboxyl halides, by two-step methoxycarbonylation of allylbarium reagents, by deconjugation of α,β-unsaturated esters, and by Horner–Wadsworth–Emmons variants of the Stobbe condensation. Sharpless asymmetric dihydroxylation of the β,γ-unsaturated esters, followed
具有立体定义的三取代 C=C 双键的 β,γ-不饱和酯是通过 α,β-不饱和羧基卤化物的 Arndt-Eistert 同系物制备的,通过烯丙基钡试剂的两步甲氧基羰基化,通过 α,β-不饱和酯的解偶联,和霍纳-沃兹沃思-埃蒙斯的 Stobbe 凝聚变体。β,γ-不饱和酯的 Sharpless 不对称二羟基化,然后自发环化,以中等至良好的产率得到 β-羟基-γ-内酯,对映体过量高达 97%。类似地,四羟基-γ-内酯是从二不饱和酯中获得的;这些内酯被转化为双内酯和不饱和β-羟基γ-内酯。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)