Preferential Geminal Bis-silylation of 3,4-Benzothiophane Is Caused by the Dominance of Electron Withdrawal by R3Si over Steric Shielding Effects

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• 作者：Yifeng Han ; Yun Ma ; Ivan Keresztes ; David B. Collum ; E. J. Corey
• 刊名：Organic Letters
• 出版年：2014
• 出版时间：September 5, 2014
• 年：2014
• 卷：16
• 期：17
• 页码：4678-4679
• 全文大小：189K
• ISSN：1523-7052

文摘

Benzylic C鈥揌 lithiation of 3,4-benzothiophane and subsequent treatment with triphenyl- or trimethylchlorosilane under a variety of conditions leads to 伪,伪- rather than 伪,伪鈥?bis-silylation products as a consequence of anion stabilization by R₃Si and very fast deprotonation of the intermediate monosilylated product, even with a sterically bulky base such as lithium diisopropylamide.