Branched amino sugars synthesis

The four isomeric methyl 2,4,6-trideoxy-4-C-methyl-4-trifluoroacetamido-L-hexopyranosides (L-ribo-. L-arabino. L-xylo. and L-lyxo-) have been synthesised from L-threonine. The synthesis of some branched-chain derivatives of daunosamine is discussed in Chapter 10. A new naturally occurring branched amino-sugar eremosamine is covered in Chapters 9 and 19. 

C-6,209,214 anhydro sugars,branched monosaccharides, fluori-nated amino sugars,difluorinated monosaccharides, and fluorinated monosaccharide phosphates,and phosphonates have been described. Further progress has been achieved in the synthesis and n.m.r.-spectral analysis of fluorinated avermectin Bu, tylono-lide, and neuraminic acid derivatives. " ... 

J. S. Brimacombe, J. A. Miller, and U. Zakir, An approach to the synthesis of branched chain amino sugars from C-methylene sugars, Carbohydr. Res. 49 233 (1976). 

W. G. Overend Some approaches to the synthesis of amino sugars and branched chain sugars... 

H. H. Baer and Z. S, Hanna, The preparation of amino sugars and branched-chain sugars by palladium-catalysed allylic substitution of alkyl hex-2-enopyranosides. Can. J. Chem. 59 889 (1981). D. P. Cuiran, An approach to the enantiocontrolled synthesis of pseudomonic acids via a novel mon-Claisen rearrangement. Tetrahedron Lett. 23 4309 (1982). 

During the past nine years the subject of total synthesis of sugars and cyclitols has been vividly developed. The discovery of a large number of unusual sugars in nature—deoxy, amino, branched chain sugars (many of them components of antibiotics)—made their synthesis attractive. On the other hand, improvements in organic reagents and synthetic methods allowed a return to older preparations which could be now better performed. Finally, some synthetic ideas already described in this series, in the first chapter of the volume on the total synthesis of carbohydrates, are further expanded. 

Full details of the synthesis of S-amino-S-deoxy-D-gluconolactam and 1-deoxynojirimycin (Vol.27, p.206) have been published, and the method, which involved reduction of a S-keto-aldonamide, has been applied to the synthesis of S-amino-S-deoxy-o-galactonolactam, 4-amino-4-deoxy-D-arabinonolactam, and a mixture of S-amino-5-deoxy-D-mannono- and L-gulono-lactams. Syntheses of a-azido-C-formyl branched-chain sugars are covered in Chapters 14 and 24. 

---