Acetonation of l-pentoses and 6-deoxy- l-hexoses under kinetic control using heterogeneous acid catalysts

Abstract

The fibrous polymer-supported sulfonic acid catalyst Smopex-101 H + proved to be an efficient catalyst for the preparation of O-isopropylidene derivatives from a series of rare sugars. Acetonation of the reducing sugars l-arabinose, l-ribose, l-xylose, l-fucose, and l-rhamnose in N, N-dimethylformamide by 2,2-dimethoxypropane or 2-methoxypropene led to the formation of the kinetically favored di- O- and/or mono- O-isopropylidene derivatives in 46–88% yields. The method consists of a simple experimental procedure which does not require predried solvents or reagents. The catalyst is easily recovered and can be regenerated making the procedure economically viable even for large-scale synthesis.