Oxidation of carbohydrates with chromium trioxide in acetic acid. III. Synthesis of the 3-hexuloses

Abstract

The D-arabino, L-lyxo, and L-xylo isomers of 3-hexulose have been synthesized by oxidation, with chromium trioxide in acetic acid, of fully acetylated derivatives of 3,4-0-ethylidene-D-mannitol, 3,4-0-ethylidene-L-iditol, and 2,4-O-benzylidene-D-glucitol, respectively. The D-ribo isomer has been obtained from the L-lyxo compound by inversion at C5. The 3-hexuloses were characterized as their crystalline di-O-isopropylidene derivatives: the arabino- and ribo-hexuloses each give three diacetals. The stereochemistry of these derivatives, and of the spiro-acetals of ketoses in general, is discussed.