121512-94-5Relevant articles and documents
Stereoselective α-sialylation with sialyl xanthate and phenylsulfenyl triflate as a promotor
Martichonok, Valeri,Whitesides, George M.
, p. 1702 - 1706 (1996)
Reaction α- and β-xanthates 2 and 3 of sialic acid with glycosyl acceptors 5-8 in the presence phenylsulfenyl triflate (PST) as a promoter in a 2:1 mixture of CH3CN/CH2Cl2 at low temperature affords α-sialosides in good yield and stereoselectivity. PST is prepared-in. situ by reacting benzenesulfenyl chloride with silver triflate. Less reactive acceptors 5 and 6 give a higher α/β ratio than more reactive allylic alcohol 7 and primary alcohol 8; α-stereoselectivity is increased in a dilute solution. A possible mechanism of the reaction that involves intermediate α- and β-nitrilium cations 16 and 17 is discussed.