The synthesis of 2′-O,4′-C-methyleneoxymethylene bridged nucleoside (2′,4′-BNACOC ) phosphoramidites and oligonucleotides containing 2′,4′-BNACOC are described. 2′,4′-BNACOC phosphoramidites bearing natural nucleobases, such as thymine, cytosine, 5-methylcytosine, adenine, and guanine were synthesized. Moreover, fully or partially 2′,4′-BNACOC -modified oligonucleotides can be prepared by using a standard protocol except for a prolonged coupling time on an automated DNA synthesizer.
