Acid-Catalyzed Reactions of Twisted Amides in Water Solution: Competition between Hydration and Hydrolysis

作者：Wang, Binju; Cao, Zexing^*

来源：Chemistry - A European Journal, 2011, 17(42): 11919-11929.

DOI：10.1002/chem.201101274

• ab initio calculations
• acid catalysis
• computer chemistry
• hydration
• hydrolysis
• twisted amides

The acid-catalyzed reactions of twisted amides in water solution were investigated by using cluster-continuum model calculations. In contrast to the previous widely suggested concerted hydration of the C=O group, our calculations show that the reaction proceeds in a practically stepwise manner, and that the hydration and hydrolysis channels of the C-N bond compete. The Eigen ion (H3O+) is the key species involved in the reaction, and it modulates the hydration and hydrolysis reaction pathways. The phenyl substitution in the twisted amide not only activates the N-CO bond, but also stabilizes the hydrolysis product through n(N)->pi(phenyl) delocalization, leading exclusively to the hydrolysis product of the ring-opened carboxylic acid. Generally, the twisted amides are more active than the planar amides, and such a rate acceleration results mainly from the increase in exothermicity in the first N-protonation step; the second step of the nucleophilic attack is less affected by the twisting of the amide bond. The present results show good agreement with the available experimental observations.

• 出版日期2011-10
• 单位厦门大学