The main work focuses on Palladium chemistry in organic synthesis to give new methodologies for functionalization of heterocycles, such as, furan, thiophenes, pyrroles and selenophenes. In addition, the second part of this thesis is a contribution to the chemistry of 1,4-C,N-dianions. The facile synthesis of pyrazole and oxazine by cyclocondensation of Hydrazone and Oxime Dianions was studied.