Conformations of higher acditols

Abstract

Analysis of stereomodels of alditols shows several conformational features in heptitols and higher members that are not readily apparent from published experimental studies on pentitols and hexitols. There are severe restrictions on possible conformations of higher alditols that contain segments of ribo or allo configuration. The higher members of the stereoregular series that starts with xylitol and iditol can have non-planar conformations free of serious non-bonded interactions. A conformational nomenclature is proposed for acyclic carbohydrates, which can be used to describe the arrangement of either the hydroxyl groups or the carbon chain, or both, and can also be used to describe conformations of segments of a chain.