59] - Oxidation with Ruthenium Dioxide and Hypochlorite: Methyl 6-Deoxy-2,3-O-isopropylidene-α-D-ribo-hexopyrano-sid-4-ulose

Abstract

Publisher Summary This chapter discusses the oxidation process with ruthenium dioxide and hypochlorite. A general method for the preparation of ketones has been the reaction of a secondary alcohol with ruthenium tetraoxide. The original method used equivalent amounts of ruthenium tetraoxide and frequently produced overoxidation of some of the ketones formed to yield lactones. In an experiment described in the chapter, both these problems were circumvented and only catalytic amounts of the ruthenium dioxide and a buffered solution of potassium periodate and potassium carbonate were used. In the absence of protecting groups that react with dilute solutions of sodium hypochlorite, the oxidation proceeds much faster and there is no need for buffering. The problem of converting ruthenium dioxide to the tetraoxide can be eliminated by prior oxidation of the inactive ruthenium dioxide using an alkaline chlorate melt oxidation followed by reduction to ruthenium dioxide in an active form.