On the Preparation and Determination of Configurational Stability of Chiral Thio- and Bromo[D1]methyllithiums

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• 作者：Anna Wieczorek ; Friedrich Hammerschmidt
• 刊名：The Journal of Organic Chemistry
• 出版年：2012
• 出版时间：November 16, 2012
• 年：2012
• 卷：77
• 期：22
• 页码：10021-10034
• 全文大小：624K
• 年卷期：v.77,no.22(November 16, 2012)
• ISSN：1520-6904

文摘

Thio- and bromo[D₁]methyllithiums (ee 99%) were generated from the respective stannanes by tin鈥搇ithium exchange at temperatures ranging from 0 to 鈭?5 掳C. Thio[D₁]methyllithiums 6 were found to be microscopically configurationally labile on the time scale of the thiophosphate-伪-mercaptophosphonate rearrangement even at 鈭?5 掳C. Thio[D₁]methyllithiums 13a and 13b underwent a thia-[2,3]-Wittig rearrangement down to 鈭?5 掳C and 13b only down to 鈭?0 掳C. The former were microscopically configurationally stable below 鈭?5 掳C, and the latter racemized completely at 鈭?0 掳C. Chiral bromo[D₁]methyllithiums are chemically unstable at 鈭?8 掳C but microscopically configurationally stable at the time scale of their addition to benzaldehyde and acetophenone.