Abstract 1'-C Deuterated H-phosphonate synthons were prepared via a 12-step procedure starting from [1'-2 H] ribose. The procedure included nucleosidation of 1'-O-acetyl-2', 3', 5'-O- tribenzoyl [1'-2 H] ribose with appropriately protected nucleobases and preparation of nucleoside-H-phosphonates by slightly modified described procedures. The automated RNA synthesis of 5'-G* C* U* A* U* UUAU-3'and 3'-AC* G* A* U* A* AAGU-5'was ...