Synthesis of Natural Products Containing Cyclohexane Units Starting from Aldohexoses

Preparation of optically active, highly functionalized carbocycles is an important issue in recent synthetic organic chemistry. Ferrier's carbocyclization reaction, which provides optically pure cyclohexanones from aldohexoses, is one of the most efficient procedures for this purpose. Chiral and highly oxygenated cyclohexanes obtained by this reaction are potentially versatile chiral building blocks in natural product synthesis. In this article, the development of catalytic Ferrier's carbocyclization reaction with mercury (II) trifluoroacetate, and total syntheses of natural products containing cyclohexane units (hygromycin A, lycoricidine, and mesembranol) starting from aldohexoses using this reaction as the key steps are described The methodology described in this article extends the usefulness of carbohydrates as chiral building blocks to the synthesis of natural products possessing cyclohexane rings in optically active forms.