Department of Chemistry, Indian Institute of Technology, Guwahati-781039, India.
Org Lett. 2009 Dec 17;11(24):5722-5. doi: 10.1021/ol902411r.
The beta-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 beta-effect is virtually nonexistent in the case of a cation, a foiled beta-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 beta-stabilizing effect of silicon.
使用 NMR 动力学研究了 C-3 位硅取代基对 2-氮杂环丁酮体系中 C-4 阳离子和自由基的β稳定作用。虽然阳离子的β效应实际上不存在，但自由基中间体观察到受阻的β效应（仅 3 倍的速率增强）。从实验和理论研究两方面都证明了反芳香性在抑制硅的β稳定作用方面起着主要作用。
