A method for the palladium-catalyzed synthesis of alkynylphosphonates from
1,l-dibromo-l-alkenes has been developed. In general, the best catalyst sys
tem for this transformation was found to be Pd(OAc)(2), dppf, H-phosphonate
, propylene oxide, DMF, 80 degreesC, The reaction appears tolerant of a ran
ge of functional groups in both the 1,l-dibromo-l-alkene and H-phosphonate
coupling partners. The synthesis of a backbone-modified thymidine dimer is
used to illustrate the application of this methodology in the synthesis of
complex target molecules.