Pd–imidate complexes as recyclable catalysts for the synthesis of C5-alkenylated pyrimidine nucleosides via Heck cross-coupling reaction

Pd–imidate complexes have been employed as efficient catalysts for the Heck alkenylation of unprotected 5-iodo-2′-deoxyuridine in acetonitrile. The protocol was also shown to work well for the unprotected 5-iodo-2′-deoxycytidine. A highly efficient scale-up synthesis of the HSV-1 inhibitor Brivudine (BVDU) is also accomplished in an overall yield of 72% over 3-steps. The catalyst also showed recyclability for 3 consecutive runs.