Role of aggregates in Claisen acylation reactions of imidazole, pyrazole, and thioesters with lithium enolates in THF.
Role of aggregates in Claisen acylation reactions of imidazole, pyrazole, and thioesters with lithium enolates in THF.
复制标题
聚集体在咪唑、吡唑和硫酯与烯醇锂在 THF 中的克莱森酰化反应中的作用。
DOI：
10.1021/ol990604b
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发表时间：
1999
期刊：
影响因子：
5.2
通讯作者：
Kim,YJ
中科院分区：
文献类型：
--
作者：
Streitwieser,A;Leung,SS;Kim,YJ
虽然苯酯与单体和两种烯醇化锂的二聚体或四聚体在THF中反应，但苯硫基苯甲酸酯与单体的反应相对快得多。类似地，咪唑酯主要与单体反应，但吡唑酯与单体和聚集体反应。结果合理化的一种机制，其中与两个锂阳离子内的烯醇化物聚集体的反应，以竞争与单体的配位是必需的。
Although phenyl esters react with both monomers and dimers or tetramers of two lithium enolates in THF, the reactions of phenyl thiobenzoates are relatively much faster with the monomers. Similarly, imidazole esters react primarily with the monomers but pyrazole esters react with monomers and aggregates. The results are rationalized by a mechanism in which coordination with two lithium cations within an enolate aggregate is required for the reaction of aggregates to compete with monomers.