Formation of 2-ketoheptoses

Ketoheptoses are rarely found in Nature, however, d-manno-heptulose was early on isolated from Avocado and later structurally elucidated. Since this heptulose was proven to act as inhibitor of glucokinase the involvement of ketoheptoses in biomedical applications became of interest and that induced a number of various synthetic approaches. This contribution focuses on syntheses of ketoheptoses both by rearrangement reactions (de Bruyn-van Ekenstein, Amadori, Bilik) as well as by chain elongation reactions (Henry, Grignard, exocyclic enolethers). An overview of synthetic activities from early approaches to more recent directions will be presented.