Suppressed β-Effect of Silicon in 3-Silylated Monocyclic β-Lactams: The Role of Antiaromaticity

详细信息    查看全文

• 作者：Subhendu Sekhar Bag ; Rajen Kundu ; Amit Basak ; Zdenek Slanina
• 刊名：Organic Letters
• 出版年：2009
• 出版时间：December 17, 2009
• 年：2009
• 卷：11
• 期：24
• 页码：5722-5725
• 全文大小：209K
• 年卷期：v.11,no.24(December 17, 2009)
• ISSN：1523-7052

文摘

The β-stabilizing effect of silicon substituent at C-3 on a C-4 cation and a radical in the 2-azetidinone systems is studied using NMR kinetics. While the β-effect is virtually nonexistent in the case of a cation, a foiled β-effect (only a 3-fold rate enhancement) is observed for a radical intermediate. From both the experimental and theoretical studies, it is demonstrated that antiaromaticity is playing the prime role in suppressing the β-stabilizing effect of silicon.