|Table 1: Sialylation with neuraminic acid derivatives.|
|Preparative yield of unprotected glycoside Sug-OR calculated on protected precursor of Sug-Cl (n.d.: not determined);|
/β ratio according to NMR data;
series of experiments demonstrated that these conditions are optimal for the reaction in the presence of AgOTf;
Recovery of the acceptor in the form LacNAcβ-O(CH2)3NH2 (11) 58%;
Recovery of the acceptor in the form LacNAcβ-O(CH2)3NH2 (11) 66%;
Reaction did not proceed without AgOTf.