Sugar enones as chiral precursors of aminosugars, thiosugars and carbocycles.

O. VARELA

University of Debrecen (Debrecen, Hungria)

Conferencia; Seminario en Universidad extranjera.; 2004

Invitación por convenio binacional

Sugar enones (dihydropyranones) are useful chiral building blocks as they present a reduced number of chiral centers and hydroxyl groups compared with the parent monosaccharides and they possess a carbonyl and olefinic unsaturations to which many synthetically useful reactions can be applied. These reactions are usually highly diastereoselective due to the presence of stereocenters in the molecule. In this seminar the use of sugar enones as chiral precursors of different type of molecules is discussed. Thus, diamino tetradeoxy sugars component of antibiotics have been synthesized from sugar enones. Carbohydrate-derived dihydropyrarones have been employed as dienophiles in Diels-Alder cycloadditions to afford optically pure carbocyclic systems. Also, Michael addition of thiols to sugar enones led to the corresponding 4-thiosugars, a model reaction for the construction of thiodisaccharides.