Synthesis and Reactivity of Model Intermediates Proposed for the Pd-Catalyzed Remote C-H Functionalization of N-(2-Haloaryl)acrylamides

We have studied the possible reaction pathways operating in the Pd-catalyzed remote C-H functionalization of N-(2-haloaryl)acrylamides from an organometallic approach. We have isolated and characterized several proposed reaction intermediates, such as sigma-alkyl-Pd complexes and spiro C,C-palladacycles, and evaluated the role of the base and the auxiliary ligands coordinated to Pd in the remote C-H activation process. In addition, the reactivity of these intermediates toward different unsaturated species such as benzyne, alkynes, and isocyanides has been studied in order to gain further insight into the reaction mechanism leading to functionalized spiro-oxoindoles.