Rearrangements Connected with the Change of Sugar Unit s

FIGURE 10.4 Transposition of the double bond in unsaturated hexose. 

3 REARRANGEMENTS CONNECTED WITH THE CHANGE OF SUGAR UNIT(S) 

One of the most common methods of the formation of the carbocyclic ring from the normal sugar ring is undoubtedly the Ferrier-H rearrangement discovered by Ferrier in 1979 [10]. It is based on an HgCl2-catalyzed rearrangement of unsaturated sugars with the C5-C6 (for pyranosides) or C4-C5 (for furanosides) exo-cyclic double bond. This method is discussed in many excellent reviews [11-13]. Such unsaturated 

FIGURE 10.5 Interconversion between epoxides and base-catalyzed rearrangement of 

FIGURE 10.6 Preparation of biologically important derivatives by transposition of a double bond. 

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