Palladium-Catalyzed Alkynylation (Sonogashira Coupling) at C-5 of the Uracil Moiety in Modified Unsaturated Pyranosyl Nucleosides - Mendonça, Francisco J B; dos Anjos, Janaína V; Sinou, Denis; de Melo, Sebastiao J; Srivastava, Rajendra M (Synthesis, 2007)