Carbohydrate mimic of 2-deoxystreptamine for the preparation of conformationally constrained aminoglycosides

The synthesis of a carbohydrate mimic of 2-deoxystreptamine (2-DOS) is described starting from d-ribose. Crucial steps of the synthesis involve a stereoselective nitroaldol condensation and deoxygenation via elimination-in situ reduction. Moreover, glycosylation of the carbohydrate 2-DOS derivative with a phenyl thioglycoside donor in the presence of TTBP and AgOTf followed by ring-closing metathesis yielded a conformationally restricted aminoglycoside analogue.