Unraveling Structure-Reactivity Relationships in SNV Reactions: Kinetics of the Reactions of Methoxybenzylidenemalononitrile, 2-(Methylthiobenzylidene)-1,3-indandione, 2-(Benzylthiobenzylid

详细信息    查看全文

• 作者：Claude F. Bernasconi ; Rodney J. Ketner ; Mark L. Ragains ; Xin Chen ; and Zvi Rappoport
• 刊名：Journal of the American Chemical Society
• 出版年：2001
• 出版时间：March 14, 2001
• 年：2001
• 卷：123
• 期：10
• 页码：2155 - 2164
• 全文大小：146K
• 年卷期：v.123,no.10(March 14, 2001)
• ISSN：1520-5126

文摘

The kinetics of the title reactions were determined in 50% DMSO-50% water (v/v) at 20 C;n-BuS^-, HOCH₂CH₂S^-, and MeO₂CCH₂S^- were used as thiolate ions. The reactions with the thiolate ionsgave rise to two separate kinetic processes. The first refers to rapid, reversible attachment of RS^- to the substrateleading to a tetrahedral intermediate (ls/jacsat/123/i10/eqn/ja003536te10001.gif">, ls/jacsat/123/i10/eqn/ja003536te10002.gif">), the second to the conversion of the intermediate to products(ls/jacsat/123/i10/eqn/ja003536te10003.gif">). In most cases all of the rate constants (ls/jacsat/123/i10/eqn/ja003536te10004.gif">,ls/jacsat/123/i10/eqn/ja003536te10005.gif">, and ls/jacsat/123/i10/eqn/ja003536te10006.gif">) could be determined. In combination withresults from previous studies, a detailed discussion regarding the effects of activating substituents and leavinggroups on rate and equilibrium constants as well as on intrinsic rate constants is presented. The reaction withOH^- only allowed a determination of ls/jacsat/123/i10/eqn/ja003536te10007.gif"> for nucleophilic attack on the substrate; in this case the tetrahedralintermediate remains at steady-state levels under all conditions.