Allopyranoside synthesis

Our initial studies were directed towards the synthesis and characterization of phenylboronate esters derived from methyl 6-deoxy-/ -D-allopyranoside, methyl a-L-rhamnopyranoside, methyl -L-fucopyranoside, and methyl 6-deoxy-/ -D-glucopyranoside. Previous work (14) in this laboratory indicated that the reaction of triphenylboroxole and methyl... 

An important step in the synthesis of paratose (3,6-dideoxy-n-rtfoo-hexose) involved the conversion of methyl 3-chloro-3-deoxy-/8-D-allopyranoside into methyl 3,6-dichloro-3,6-dideoxy-/8-D-allo-pyranoside in 33% yield.359... 

Y. Ali and A. C. Richardson, The reduction of azides with sodium borohydride. A convenient synthesis of methyl 2-acetamido-2-deoxy4,6-0-benzylidene-a-D-allopyranoside, Carbohydr. Res., 5 (1967) 441 448. 

E. H. Williams, W. A. Szarek, and J. K. N. Jones, Iheparation of unsaturated carbohydrates from methyl 4,6-0-benzylidene-3-chloro-3-deoxy-p-D-allopyranoside, and their utility in the synthesis of sugars of biological importance, Carbohydr. Res. 20 49 (1971). 

K. Hattori, T. Yoshida, and T. Uryu, Ring-opening polymerization and copolymerization of a new benzylated l,6-anhydro-3-azido-3-deoxy-/S-D-allopyranose and synthesis of amino-polysaccharides with 1,6-u-allopyranosidic structure, Macromol. Chem. Phys., 198 (1997) 29-39. 

H. W. C. Raaijmakers, B. Zwanenburg, and G. J. F. Chittenden, An alternative synthesis of methyl 2,3-anhydro-4,6-0-benzylidene-a-D-allopyranoside using carbonate esters, Carbohydr. Res., 238 (1993) 185-192. 

Recent applications of this reaction include the reduction of methyl 3-0-benzyl-2-O-methyl-6-O-p-tolylsulfonyl-a-D-allopyranoside, leading to the synthesis of 6-deoxy-2-0-methyl-D-allose, and the reduction of methyl 3-0-methyl-2,6-di-0-p-tolylsulfonyl-a-D-allopyrano-side as a step in the synthesis of 6-deoxy-3-0-methyl-D-allose. The last-named compound was also synthesized, in lower yield (because of competing side-reactions), starting from methyl 3-0-methyl-2,4,6-tri-0-p-tolylsulfonyl-a-D-allopyranoside. 

Synthesis of (14)-linked disaccharide glycosides of the 2,3-anhydro-4-0-(hex-2-enopyranosyl)-Q -D-allopyranoside type has been reported (Scheme 3). ... 

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