Cyanohydrins and Aminocyanides as Key Intermediates to Various Spiroheterocyclic Sugars

Derivatives with a double functionalization attract great interest in organic synthesis. The association on the same carbon atom of a nitrile group and a hydroxyl or amine function allows access to promising heterocyclic compounds of particular interest resulting from reactions taking advantage of the electrophilic character of the cyano group and the nucleophilic character of hydroxyl and amino groups. Thus, α-hydroxynitriles (cyanohydrins) or α-aminonitriles represent important classes of organic intermediates. The development of these families in glycochemistry has allowed syntheses of compounds with chain elongations (Kiliani-Fischer synthesis, Strecker synthesis) or even the preparation of chiral building blocks versatile in asymmetric syntheses of biologically active compounds or their intermediates. In this chapter, we summarize the synthesis of quaternized glycoderivatives such as cyanohydrins or glycoaminonitriles and their uses as intermediates to access spiro-heterocycles. Beyond the great structural diversity, stereochemical aspects will also be identified.