Direct synthesis of β-mannopyranosides by the sulfoxide method

摘要

In a recent extension of Kahne's sulfoxide glycosy- lation method, we reported that activation of the glycosyl donor 1 with triflic anhydride (Tf_2O_ and 2,6-di-tert-butyl- 4-methylpyridine (DTBMP) at -78 deg C in ether/arene mixtures followed by addition of a primary glycosyl acceptor resulted in the formation of mannopyranosides in high yield and high β:α-ratios (protocol A).