Regioselective Monoesterification Study of the Diol in 1-C-(4,6-O-Benzylidene-β-D-glucopyranosyl) Acetone

Abstract

1-C-(4,6-O-Benzylidene-β-D-glucopyranosyl) acetone has been studied in a catalytic system consisting of triethylamine-p-dimethylaminopyridine (TEA-DMAP) in the presence of a number of esterification reagents in dichloromethane. It was found that all-protected and monoprotected products form simultaneously. However, the regioselectivity tends to favor the 3-substituted derivative. Structural parameters have been determined by ¹H NMR, ¹³C NMR, ¹H-¹H correlation spectroscopy, and elemental analysis. Furthermore, a possible mechanism for the formation of intramolecular hydrogen-bond networks between the carbonyl group and 2-OH was described. The energy changes of the transition state in this reaction, as determined by a molecular modelling study, provided further evidence to assign the relative reactivities of each individual hydroxyl group.

GRAPHICAL ABSTRACT

Keywords:

• C-Glycosides
• NMR
• regioselective protection

ACKNOWLEDGMENT

We thank Dr. Wu X. D. for helpful discussions on NMR analysis.

SUPPLEMENTAL MATERIAL

¹H NMR, ¹³C NMR, ¹H-¹H COSY spectra, and molecular computation data for this article can be accessed on the publisher’s website.