| الوصف: |
Glycals, systematically named l,5-(or 1,4-)anhydro-2-deoxy-hex-(or -pent-)l--enitols, posses a double bond between C-l and C-2 carbon atoms of a pyranose or furanose ring and are one of the most useful substrates in carbohydrate chemistry. Presence of the double bond in glycals makes them possible to undergo variety of the reactions, including different additions, hydroxylation, epoxydation, cycloadditions, allylic rearrangement and many others. The majority of these reactions were described in 1960s and 1980s by Ferrier. However, applications of glycals, especially as glycosyl donors, have been systematically developed and new methodologies have been employed in the last decade. This paper presents useful procedures, mainly resulting in the stereoselective synthesis of a glycoside bond. The presented applications of glycals are divided into following groups: addition of water, synthesis of 2-deoxyglycosides, synthesis of 2-amino--2-deoxyglycosides, synthesis of glycosides possessing 2-hydroxy group, Ferrier rearrangement, formation ofthe [alfa,beta]-unsaturated aldehydes, cyclopropanation and cycloaddition. |