Halogen–lithium exchange versus deprotonation: synthesis of diboronic acids derived from aryl–benzyl ethers
- 作者：Tomasz Kliś ; ; Janusz Serwatowski
- 关键词：Lithiation ; Aryl– ; benzyl ethers ; Butyllithium ; Diboronic acid
- 刊名：Tetrahedron Letters
- 出版年：2007
- 期刊代码：109_00404039
- 类别：ch
- 出版时间：12 February 2007
- 卷：48
- 期：7
- 页码：1169-1173
- 文件大小：136 K
摘要
Lithiation of a series of aryl benzyl ethers containing halogen substituents (–F, –Br, –I) was investigated. The resultant mono- and diorganolithium intermediates were converted into the corresponding aldehydes or diboronic acids in good yields. The dilithiation of aryl benzyl ethers containing a reactive hydrogen atom and halogen atom capable of halogen–lithium exchange proceeds quantitatively in THF at −50 °C. It was found that mono aryllithiums formed in the reaction can remove the reactive hydrogen atom from a molecule of aryl benzyl ether thus decreasing the yield of dilithiated species. This effect does not occur when t-BuLi is used instead of n-BuLi.