BiBr3-catalyzed benzylation of alcohols.: Stereochemistry and mechanistic investigations
BiBr3-catalyzed benzylation of alcohols.: Stereochemistry and mechanistic investigations
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DOI：
10.1016/s0040-4020(01)00014-x
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发表时间：
2001-03-03
期刊：
影响因子：
2.1
通讯作者：
Roque, JP
中科院分区：
文献类型：
--
作者：
Keramane, EM;Boyer, B;Roque, JP
我们研究了光学活性脂肪醇（辛烷-2-醇和丁烷-2-醇）以及顺式和反式2-甲基环己醇或(S)-(-)-薄荷醇的苄基化反应，在（-）或(+/-)-1-苯乙醇（PeOH）存在下，由溴化铋（III）催化。在温和的条件下，脂肪族醇提供非对映异构体醚的等摩尔混合物，而脂环醇产生具有构型保留的醚。为了解释这些结果，我们假设BiBr3作为Lewis酸，会导致6倍配位铋中间体的形成，涉及两个1-苯乙醇分子和一个脂肪醇分子。我们提出了一种机制来解释这些bibr3促进的醚化反应。2001爱思唯尔科学有限公司版权所有。
We have investigated the benzylation of optically active aliphatic alcohols (octan-2-ol and butan-2-ol) as well as cis and trans 2-methylcyclohexanol or (S)-(-)-menthol, catalyzed by bismuth (III) bromide in the presence of(-) or (+/-)-1-phenylethanol (PeOH). Under mild conditions, aliphatic alcohols provided an equimolar mixture of diastereomeric ethers while alicyclic alcohols gave rise to ethers with retention of configuration. To explain these results, we assumed that BiBr3, acting as Lewis acid, would lead to the formation of a 6-fold coordinated bismuth intermediate involving two molecules of 1-phenylethanol and one molecule of aliphatic alcohol. We have proposed a mechanism to explain these BiBr3-promoted etherification reactions. (C) 2001 Elsevier Science Ltd. All rights reserved.