Kinetic and computational evidence for an intermediate in the hydrolysis of sulfonate esters

被引：15
|
作者：
Babtie, Ann C. [2 ]
Lima, Marcelo F. [1 ,2 ]
Kirby, Anthony J. [1 ]
Hollfelder, Florian [2 ]
机构：
[1] Univ Cambridge, Dept Chem, Cambridge CB2 1EW, England
[2] Univ Cambridge, Dept Biochem, Cambridge CB2 1GA, England
来源：
ORGANIC & BIOMOLECULAR CHEMISTRY | 2012年 / 10卷 / 40期
基金：
英国工程与自然科学研究理事会; 英国生物技术与生命科学研究理事会;
关键词：
ALKALINE-PHOSPHATASE SUPERFAMILY; P-NITROPHENYL PHOSPHATE; SINGLE TRANSITION-STATE; CATALYTIC PROMISCUITY; SULFATE ESTERS; REACTIVITY; MECHANISM; NUCLEOPHILES; INHIBITION; METABOLISM;
D O I：
10.1039/c2ob25699a
中图分类号：
O62 [有机化学];
学科分类号：
070303 ; 081704 ;
摘要：
The hydrolytic reactions of sulfonate esters have previously been considered to occur by concerted mechanisms. We now report the observation of a break in a Bronsted correlation for the alkaline hydrolysis of aryl benzenesulfonates. On either side of a break-point, beta(leaving) group values of -0.27 (pK(a) < 8.5) and -0.97 (pK(a) > 8.5) are measured. These data are consistent with a two-step mechanism involving a pentavalent intermediate that is also supported by QM/MM calculations. The emerging scenario can be explained by the combined effect of a strong nucleophile with a poor leaving group that compel a usually concerted reaction to favour a stepwise process.
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页码：8095 / 8101
页数：7
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