Syntheses of specified 2′-modified nucleosides were achieved: a) via oximation of the 5′,3′-blocked 2′- oxocytidine, followed by reduction, or b) by intramolecular nucleophilic addition of 3′-(2- methoxyethoxy)- carbamate to the 2′-position with openingof O2,2′-anhydrouridine. For the first time, 3′-phosphoroamidites of these 2′-modified nucleosides were successfully incorporated into oligonucleotides by solid-phase synthesis. Incorporation of 2′-modified nucleotides into oligodeoxyribonucleotides had a negative effect on the duplex Tm values with the DNA or RNA complements. Nevertheless, modified nucleotides have shown good target recognition; the (S)-isomer binds preferably to RNA and the (R)-isomer to DNA. Both modified nucleosides significantly increased nuclease resistance of the oligodeoxyribonucleotides.