A novel palladium-catalysed coupling strategy for the rapid synthesis of nucleic acid analogues bearing modified backbones

The synthesis of a 5'-deoxy-5'-methylidene phosphonate-containing thymidine dimer 14 has been achieved using a palladium-catalysed cross coupling reac tion as a key step. The E-vinyl bromide 9 was synthesised from the correspo nding 1,1-dibromoolefin 7 via selective reduction using dimethylphosphite a nd triethylamine.