Concerted general acid and nucleophilic catalysis of acetal hydrolysis. A simple model for the lysozyme mechanism
作者:Kathryn E. S. Dean、Anthony J. Kirby
DOI:10.1039/b110948k
日期:2002.2.25
The monoanion is the most reactive ionic form of the symmetrical formaldehyde acetal of 4-hydroxybenzofuran-3-carboxylic acid 1. The evidence is consistent with a mechanism in which the carboxylate anion acts as a nucleophile to assist the general acid catalysed cleavage of the C–O bond to the leaving group: the initial product is the cyclic acylal 5 and the extra acceleration derived from the participation
单阴离子是对称甲醛缩醛的最活泼的离子形式 4-羟基苯并呋喃-3-羧酸 1。证据与羧酸根阴离子充当亲核试剂以协助一般酸催化离去基团的C-O键裂解的机理是一致的:初始产物是环状酰基5,并且由于参与而产生了额外的加速作用相邻亲核试剂中的一个(通过一个没有希望的7元环)比特定酸催化的预期速率贡献了大约两个数量级,从而使总速率提高了近五个数量级。