Stereochemistry of the cyclization of alkoxy-substituted 5-hexenyllithiums: effect of solvent and lithium iodide on diastereoselectivity
Stereochemistry of the cyclization of alkoxy-substituted 5-hexenyllithiums: effect of solvent and lithium iodide on diastereoselectivity
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DOI：
10.1016/j.tet.2005.01.042
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发表时间：
2005-03-28
期刊：
影响因子：
2.1
通讯作者：
Jiang, XL
中科院分区：
文献类型：
--
作者：
Bailey, WF;Jiang, XL
研究了低温锂碘交换生成的4-甲氧基-5-己烯基锂、4-（甲氧基甲氧基）-5-己烯基锂、4-叔丁基-5-己烯基锂和3-甲氧基-5-己烯基锂在多种溶剂体系中的立体化学反应。这些研究结果表明，烷氧基取代的5-己烯基锂环化的立体化学结果可能受到进行环闭合的介质的深刻影响。这些通常戏剧性的溶剂效应的病因是由于某些亲锂配体能够竞争性地络合碘化锂盐，而碘化锂盐是用于制备有机锂的交换反应的副产物。(c) 2005 Elsevier Ltd版权所有。
The stereochemistry of the cyclization of 4-methoxy-5-hexenyllithium, 4-(methoxymethoxy)-5-hexenyllithium, 4-tert-butoxy-5-hexenyllithium, and 3-methoxy-5-hexenyllithium, each of which was generated from the corresponding iodide by low-temperature lithium-iodine exchange, has been studied in a variety of solvent systems. The results of these studies demonstrate that the stereochemical outcome of the cyclizations of alkoxy-substituted 5-hexenyllithiums may be profoundly affected by the medium in which the ring closures are conducted. The etiology of these often dramatic solvent effects is attributed to the ability of certain lithiophilic ligands to competitively complex the lithium iodide salt that is present as a co-product from the exchange reaction used to prepare the organolithiums. (c) 2005 Elsevier Ltd. All rights reserved.