Effect of solvent and temperature on the lithium-iodine exchange of primary alkyl iodides:: reaction of t-butyllithium with 1-iodooctane in heptane-ether mixtures
Effect of solvent and temperature on the lithium-iodine exchange of primary alkyl iodides:: reaction of t-butyllithium with 1-iodooctane in heptane-ether mixtures
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DOI：
10.1016/s0022-328x(03)00609-0
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发表时间：
2003-09-12
影响因子：
2.3
通讯作者：
Jordan, KP
中科院分区：
文献类型：
--
作者：
Bailey, WF;Brubaker, JD;Jordan, KP
本文研究了具有代表性的伯烷基碘1-碘辛烷与t-BuLi在庚烷和四种不同比例的二烷基醚组成的溶剂体系中于0 ℃下的反应。偶联和消除是不可避免的副反应，当反应在0 ℃下进行时，伴随着锂-碘交换。在纯烃溶剂中缓慢的交换反应通过存在基本上催化量的醚助溶剂而显著促进。对于所研究的每种醚，最佳的醚-庚烷比使l-碘辛烷和tBuLi之间的锂-碘交换程度最大化，但在任何情况下，当反应在0 ℃进行时，辛基锂的产率（以辛烷计）都不超过90%。在较低温度下，在庚烷-MTBE（体积比19：1）组成的溶剂体系中，副反应得到抑制，辛基锂的产率接近定量。(C)2003 Elsevier B.V.保留所有权利。
The reaction of l-iodooctane, a representative primary alkyl iodide, with t-BuLi at 0degreesC in solvent systems composed of heptane and four dialkyl ethers in various proportions has been investigated. Coupling and elimination are unavoidable side reactions that accompany lithium-iodine exchange when the reactions are conducted at 0degreesC. The exchange reaction, which is slow in pure hydrocarbon solvent, is significantly facilitated by the presence of essentially catalytic quantities of an ether co-solvent. An optimal ether-heptane ratio for each of the ethers surveyed maximizes the extent of lithium-iodine exchange between l-iodooctane and tBuLi but in no case does the yield of octyllithium, assayed as octane, exceed similar to90% when reactions were conduced at 0degreesC. At lower temperatures, in a solvent system composed of heptane-MTBE (19:1 by volume), side reactions are suppressed and the yield of octyllithium approaches quantitative. (C) 2003 Elsevier B.V. All rights reserved.