Hydrolysis of O-Isopropenyl Glucopyranosides Involves C-Protonation and Alkenyl Ether Cleavage and Exhibits a Kinetic Influence of Anomeric Configuration
作者:H. Keith Chenault、Laura F. Chafin
DOI:10.1021/jo00100a015
日期:1994.10
Hydrolysis of O-isopropenyl alpha-glucopyranoside occurs by C-protonation and alkenyl ether (not glycosidic) C-O bond cleavage and proceeds in 10 mM salicylate buffer, at pH 3.0 and 25 degrees C, 4.5 times faster than the similar hydrolysis of its beta anomer.
Mechanism of Hydrolysis of Isopropenyl Glucopyranosides. Spectroscopic Evidence Concerning the Greater Reactivity of the α Anomer
作者:H. Keith Chenault、Laura F. Chafin
DOI:10.1021/jo9721249
日期:1998.2.1
shown to undergo hydrolysis exclusively by cleavage of the vinyl ether and not the acetal C-O bond. While both glucopyranosides undergo irreversible, rate-limiting C-protonation, 1 hydrolyzes approximately four times faster than 2 and has an enthalpy of activation that is 5.8 kcal mol(-)(1) lower than that of 2, suggesting that 1 is kinetically more basic than 2. Spectroscopic evidence indicates that conjugation