C2-Symmetric Enantiopure Ethanotethered Bis(α,β-butenolides) as Templates for Asymmetric Synthesis. Application to the Synthesis of (+)-Grandisol1
C2-Symmetric Enantiopure Ethanotethered Bis(α,β-butenolides) as Templates for Asymmetric Synthesis. Application to the Synthesis of (+)-Grandisol1
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C2-对称对映体乙醚双（α,β-丁烯内酯）作为不对称合成模板在 (+)-Grandisol1 合成中的应用。
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发表时间：
2003
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通讯作者：
J. Piniella
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作者：
P. March;M. Figueredo;J. Font;J. Raya;A. Alvarez;J. Piniella
以d-甘露醇为原料，合成了几种C2对称的乙基系联双(α，β-丁烯内酯)，并研究了它们与乙烯的[2+2]光环加成反应。中心二醇单元的保护基团对环加成反应的表面选择性有显著影响，双(三甲基硅氧基)衍生物表现出最高的非对映选择性。基态底物的理论构象分析与实验观察到的非对映界面选择性很好地吻合。由γ-羟甲基-α，β-丁烯内酯与乙烯的光反应，将双(光环加合物)转化为对映体环丁烷，仅有中等的表面选择性。作为这些研究的应用，我们开发了一种高效、立体选择性地合成(+)-格拉迪索。
Starting from d-mannitol, we have prepared several C2-symmetric ethanotethered bis(α,β-butenolides) and studied their [2+2] photocycloaddition reaction with ethylene. The protective groups of the central diol unit have a noticeable influence on the facial selectivity of the cycloaddition, the bis(trimethylsilyloxy) derivatives showing the highest diastereoselectivity. A theoretical conformational analysis of the substrates in the ground state is in good agreement with the diastereofacial selectivity experimentally observed. The bis(photocycloadducts) have been converted into the enantiopure cyclobutanes formally derived from the photoreaction of ethylene with γ-hydroxymethyl-α,β-butenolide, in which only a moderate facial selectivity had been previously found. As an application of these studies, we have developed a highly efficient and stereoselective synthesis of (+)-grandisol.