ABSTRACT The ketene dithioacetal formation is generally regarded as highly efficient method for the direct one carbon homologation of ketones and aldehydes. Typical ketene dithioacetal formation proceeds via Horner-Emmons or Peterson olefination reaction. These compounds are extremely useful synthetic equivalents of carbonyl compounds as they are easily convertable into aldehydes, carboxylic acids and esters. This review is focused on the application of ketene dithioacetal methodology to the synthesis of unusual carbohydrates. Special attention is paid to the unprecedented, successful formation of ketene dithioacetals from sugar 2-deoxy-1,5-hexonolactones, developed in our laboratory. Besides, these intermediates enabled the construction of a variety of isomeric 3-deoxy-2-ulosonic acids and their 2-deoxy counterparts, among them DAH and KDO. Further, ketene dithioacetals were employed in the direct, efficient and stereospecific synthesis of biologically relevant KDO disaccharides.
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