Glycosidation via conjugate addition of anomeric alkoxides to nitroalkenes and nitrosoalkenes

The conjugate addition of protected pyranose alkoxides to 1-nitro- and 1-nitrosoalkenes gave 2-nitroalkyl and 2-oximinoalkyl glycosides. In several cases, the reaction proceeded with preferential formation of the α-glycoside (α:β ⩽ 4:1). The methodology was employed in model (L)-rhodinosylation reactions relevant to the total synthesis of lactonamycin.