Naslov
Hydrolysis and retro-aldol cleavage of ethyl threo-2-(1-adamantyl)-3-hydroxybutyrate: competing reactions

Autori
Ganguly, Bishwajit ; Singh, Ajeet ; Matković, Marija ; Basarić, Nikola ; Kesharwania, Manoj K. ; Mlinarić-Majerski, Kata

Izvornik
Journal of physical organic chemistry (0894-3230) 24 (2011), 7; 578-587

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
ester hydrolysis; retro-aldol; DFT; solvent effect; adamantane

Sažetak
The hydrolysis of ethyl threo-2-(1-adamantyl)-3-hydroxybutyrate (1) and the parent ester ethyl 3-hydroxybutyrate (4) has been studied experimentally and computationally. In the hydrolysis of threo-ester 1 with 2M NaOH, predominantly retro-aldol product was observed, whereas the hydrolyzed product was present in a minor amount. When the reaction is carried out under the same conditions with the parent ester ethyl 3-hydroxybutyrate (4), hydrolyzed product is exclusively observed. The competitive pathways, namely hydrolysis and the retro-aldol reaction for 1 and 4 were investigated using DFT calculations in the both gas and solvent phases. The calculated results at B3LYP/6-31+G* level revealed that the formation of retro-aldol products is kinetically and thermodynamically preferred over the hydrolysis of threo-ester 1 in the presence of a base. However, in methanol, the parent ester 4 showed that the retro-aldol process is less favored than the hydrolysis process. The bulky adamantyl group enhances the activation barriers for the hydrolysis of the ethyl threo-2-(1-adamantyl)-3-hydroxybutyrate (1) through deleterious steric interaction with the nucleophile compared to parent ester ethyl 3- hydroxybutyrate (4).

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA