New phosphorylating reagents for deoxyribonucleosides and oligonucleotides

New phosphorylating reagents 1 and 2 were prepared in three steps from 4-hydroxybenzaldehyde. They showed good efficiency in the solid phase synthesis of 5′-phosphate monoester nucleosides. End-phosphate DNA sequence synthesis demonstrated the efficiency of the new reagents ( 1 and 2 ) according to the general procedure of automated DNA synthesis. The oxidation of P(III) to P(V) and the removal of benzyl protecting groups were achieved in a single step by treatment with a 0.02 M I 2 /pyridine/H 2 O solution. Due to this one-pot treatment, it is possible to use the phosphorylating reagents ( 1 and 2 ) for the synthesis of base-sensitive ODNs. The reagents 1 and 2 are unique among phosphorylating reagents.