Lactams glycoside-derived, synthesis

Many rearrangement reactions are initiated by BF3 complexes in the presence of acetic anhydride, including the synthesis of functionalized and optically active pyrans from (+)-(/ ,R)-diethyl tartrate (Eq. 41) [74]. Other examples include the conversion of bicyclic into monocyclic [75] and tricyclic into bicyclic systems [76], the acetolysis of glycosides resulting in the formation of the fully acetylated acyclic derivative [77], and the unusual migration of nitrogen in the dienone-phenol rearrangement of an N-methoxy-/ -lactam [78]. 

Synthesis of Monosaccharide Derivatives.—New approaches to the synthesis of glycosides, including the alkoxylation of N-furanosyl-lactams, the reaction of l-0-acetyl-2,3,5-tri-0-benzoyl-P-D-ribofuranose with cyclic amide acetals derived from vicinal diols (see Vol. 10, p. 16), the Lewis acid-catalysed alcoholysis of sugars with an activated anomeric centre (see Vol. 10, p. 11), and the glycosidation of glycopyranosyl halides catalysed by silver trifluoromethanesulphonate (triflate), have been reviewed. A general review of carbonyl compounds has also dealt with some aspects of glycoside synthesis. 

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