An efficient and highly diastereoselective synthesis of C-glycosylated 1,3-oxazolidines from N-methyl-d-glucamine

A one-pot procedure for preparing chiral 1,3-oxazolidines derived from N-methyl-d-glucamine and aryl aldehydes is described. It has been carried out by using readily available reagents and operationally simple conditions allowing the preparation of the acyclic C-nucleoside analogs in high yields. The structure of these derivatives has been fully characterized by NMR correlations and single-crystal X-ray diffraction. Some reactions also provide access to the corresponding tetrahydro-1,3-oxazines by an alternative ring closure. Mechanistic considerations account for the observed steric course.