Orthogonal cleavage of the 2-naphthylmethyl group in the presence of the p-methoxy phenyl-protected anomeric position and its use in carbohydrate synthesis

Orthogonal removal of naphthylmethyl (NAP) and anomeric O-p-methoxyphenyl (PMP) ethers using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and cerium(IV) ammonium nitrate, respectively, is described. These reactions were tested in the oligosaccharide assembly of biologically relevant motifs, such as alpha-D-Man-(1,3)-[alpha-D-(1,6)-Man]-alpha-D-Man, alpha-D-Fuc-(1,2)-alpha-D-Fuc and alpha-D-NeuNAc-(2,3)-beta-D-Gal. The usefulness of these chemoselective deprotections was proven in the synthesis of high mannoses.