Glycosyl donor reactivity

Firstly, the reactivity of the glycosyl donor can be varied over wide ranges by the choice of the halogen, the protecting group pattern, the catalyst, the solvent and the temperature. In this way the glycosyl donor reactivity can be adjusted to the glycosyl acceptor reactivity (which can also be varied). 

Electronically different LGs have also been incorporated to tune the glycosyl donor reactivity (Scheme 6.8). One of the first examples described the use of selenoglycosids in the presence of thioglycosides. While Mehta and Pinto used silver triflate to selectively activate the seleno derivative 34-the benzylated sulfur compound 35 did not react-for the synthesis of disaccharide 36 [38, 39], iodonium sources became more common for numerous applications of this concept in one-pot... 

Pedersen CM, Marinescu LG, Bols M (2008) Conformationally armed glycosyl donors reactivity quantification, new donors and one pot reactions. Chem Commun 2465-2467... 

The evidence in Scheme 4 makes it clear that success in oligosaccharide coupling can be dependent on protecting groups present on the reactants. A procedure for direct comparison of glycosyl donor reactivity would be advantageous, and such a methodology was therefore developed [10]. 

Glycosyl sulfones, normally of low reactivity, have been reported as glycosyl donors, activated by magnesium bromide etherate.188... 

The schematic outline of the stepwise selective activation is shown in Scheme 1.9 thus, a glycosyl donor, bearing a reactive LGa, is coupled with a glycosyl acceptor,... 

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