Development and application of novel alkoxymethyl groups

Protecting groups (PGs)still occupy an important position in the organic synthesis, despite negative campaign declaring that the use of them is not step-economical. Although an enormous number of PGs have been developed to date, there still are demands of new PGs that can be installed and cleaved at the desired timing and situation. Recently, we have focused on some projects to revisit the usefulness of alkoxymethyl PGs. In this review article, the property of 2- naphthylmethoxymethyl (NAPOM or NOM)and 1-naphthylmethoxymethyl (1-NAPOM, NAPOM I or NOM I)groups, our newly developed alkoxymethyl PGs, would first be introduced. Subsequently, application of the alkoxymethyl PGs to peptide- and glyco-chemistry was discussed. In the peptide chemistry, the NAPOM group was introduced on a π -nitrogen of histidine to suppress the racemization during peptide synthesis. On the other hand, in the glycochemistry, alkoxymethyl PGs were installed on a hydroxy group at C2 position, and used for the anchimeric assistance to ensure 1,2-trans selective glycosylation. Furthermore, because 2-O-alkoxymethyl protected donors were found to be more reactive than the conventional 2-O-acyl ones, a one-pot strategy for the synthesis of 1,2-trans oligosaccharides could be developed.