Saccharides coupling

D. R. Mootoo, P. Konradsson, U. E. Udodong, and B. Fraser-Reid, Armed and disarmed n-pentenyl glycosides in saccharide couplings leading to oligosaccharides, J Am. Chem. Soc. 770 5583 (1988). 

Alkyl ethers can act as nucleophiles in cyclofunctionalization reactions,17 and recently acetal oxygens have been shown to be excellent nucleophiles for participation in heteroatom cyclizations (Scheme 9). This reaction has been used as a nonhydrolytic procedure for unraveling complex acetals (conversion of 9 to 10),180 for specific liberation of an anomeric center (conversion of 11 to 12),181a for preparation of glycosyl bromides18115 and for saccharide coupling (reaction of 13 and 14 to give 15).182... 

Fraser-Reid B, Wu Z, Andrews CW, Skowronski E. Torsional effects in glycoside reactivity saccharide couplings mediated by acetal protecting groups. J. Am. Chem. Soc. 1991 113 1435-1437. 

Mathew, L, Jayaprakash, K N, Lraser-Reid, B, Mathew, J, Scicinski, J, Microwave-assisted saccharide coupling with n-pentenyl glycosyl donors. Tetrahedron Lett., 44, 9051-9054, 2003. 

Fraser-Reid B, Lopez JC, Gomez AM, Uriel C. Reciprocal donor acceptor selectivity (RDAS) and Paulsens concept of match in saccharide coupling. Eur J Org Chem 2004 1387-1395. 

The treatment of pent-4-enyl glycosides with bromine has allowed an exceptionally mild new synthesis of glycosyl bromides, galactoside (21) affords bromide (22). The yields are high and the reactions are generally sufficiently specific for the products to be used in situ for saccharide coupling. ... 

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