STUDY ON ACID-CATALYZED ADDITION OF HEMIACETAL HYDROXYLS TO ISOBUTYLENE - SYNTHESIS OF TERT-BUTYLGLUCOSIDES

When acetylated reducing sugars, in dichloromethane, were reacted with isobutylene CH2=C(CH1)2in the presence of a catalytic amount of H2SO4or TsOH, tert-butyl glycopyra-nosides were obtained in fairly good yield (60 to 90%). Moreover, it was shown that experimental conditions allow control of the stereochemistry at the anomeric carbon. Careful examination of the results showed that the reaction was mainly governed by the rate of the anomerization and the difference in reactivity between equatorial and axial hemiacetal hydroxyl groups. © 1990, Taylor & Francis Group, LLC. All rights reserved.