Efficient synthesis of acetals catalysed by rare earth chlorides
Efficient synthesis of acetals catalysed by rare earth chlorides
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DOI：
10.1039/c39780000976
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
J. Luche;A. Gemal
中科院分区：
文献类型：
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作者：
J. Luche;A. Gemal
稀土系列元素及其衍生物很少受到有机化学家的关注，尽管它们用于合成目的似乎很有希望。 1 我们现在报道稀土氯化物是醛缩醛化的高效催化剂。缩醛化和二氧戊环形成是保护醛和酮基团最有效和最常用的方法。 2 在醇存在下，这些化合物在酸催化的平衡反应中形成缩醛。通常，该转化是通过 2, Z-二甲氧基丙烷或原甲酸三甲酯的存在来完成的。~ p 3 已经描述了使用各种催化剂的几种方法，例如质子酸 4 或路易斯酸（FeCl, NH, NO3, BF3, ZnCl,）, 5。
ELEMENTS of the rare earths series and their derivatives have received scarce attention from organic chemists, although their use for synthetic purposes seems to be promising. 1 We now report that the rare earths chlorides are highly efficient catalysts for the acetalization of aldehydes.Acetalization and dioxolan formation are the most efficient and usual methods for the protection of aldehyde and ketone groups. 2 In the presence of an alcohol, these compounds form acetals in an acid-catalysed, equilibrated reaction. Usually the transformation is brought to completion by the presence of 2, Z-dimethoxypropane or trimethyl orth~ formate.~ p 3 Several methods using various catalysts, such as protic acids4 or Lewis acids (FeCl,, NH, N03, BF3, ZnCl,), 5 have been described.