The reaction of 6-trifluoromethanesulfonyloxy-4 (3H)-pyrimidinones with Me2Cu (CN) Li2, and with vinyl tributyltin, trimethylsilylacetylene, and zinc cyanide with palladium catalysis, are described for the synthesis of a variety of fully functionalized 6-substituted-4 (3H)- pyrimidinones of interest as herbicides.