Iron Complexes in Carbohydrate Chemistry

Abstract

Formation and synthetic applications of carbohydrate-iron complexes possessing C-metal bond are discussed. Some of these intermediates are stable and can be isolated and characterized. In many instances, however, the sugar carbon-iron complexes exhibit a limited stability and are directly converted into the final products without their prior isolation and characterization. Nevertheless, the presence of such complexes can be inferred from spectral data. In this review the emphasis is put on the applications of carbohydrate-iron complexes in the synthesis of a less common sugar derivatives. Thus, de novo synthesis of mycaminose, an antibiotic sugar, is described employing an intermediary amino-dienone tricarbonyliron complex. Sodium (η5-cyclopentadienyl)-dicarbonyl-iron served as a source for the CO group insertion into derivatives of methyl β-D-glucopyranoside. A general method of deoxysugar synthesis was proposed starting from monosaccharide aldehydes and anion obtained from (η5-cyclopentadienylcarbonyl- triphenylphosphine-acetyl-iron (“acetyl-iron”). In that manner several derivatives of deoxy-pentoses, - hexoses as well as a series of 6-deoxy heptoses were obtained. Reactions of acetyl- and propionyl-iron anions with hexofuranose epoxides led to the heptofuranose lactones. Also, reactions of sugar aldehydes with anion derived from “(methylthioacetyl)iron” are described. The review presents the literature from 1979 (first applications of iron complexes in carbohydrate chemistry) to 2001, inclusively, 39 references. Keywords: iron complexes, carbohydrate chemistry, carbohydrate-iron complexes, (methylthioacetyl), mycaminose, antibiotic sugar, amino-dienone tricarbonyliron