Synthetic Studies on the Validamycins. III. Bromination of <scp>Dl</scp>-Tri-<i>O</i>-acetyl-(1,3/2)-4-methylene-5-cyclohexene-1,2,3-triol. Preparation of Several Branched-chain Unsaturated Cyclitols Related to Valienamine

Abstract

Abstract Bromination of Dl-tri-O-acetyl-(1,3/2)-4-methylene-5-cyclohexene-1,2,3-triol with bromine in an appropriate solvent yielded mainly two 1,4-addition products, from which several branched-chain unsaturated cyclitols, related to biologically interesting valienamine, were selectively prepared. Reaction courses are discussed for the bromination of the diene and the debromination of the bromo(bromomethyl)cyclohexenetriol triacetates obtained under various conditions.