Site Selectivity in Pd-Catalyzed Reactions of α-Diazo-α-(methoxycarbonyl)acetamides: Effects of Catalysts and Substrate Substitution in the Synthesis of Oxindoles and ß-Lactams.

The Pd-catalyzed intramolecular carbene C-H insertion of α-diazo-α-(methoxycarbonyl)acetamides to prepare oxindoles as well as ß-lactams was studied. In order to identify what factors influence the selectivity of the processes, we explored how the reactions are affected by the catalyst type, using two oxidation states of Pd and a variety of ligands. It was found that, in the synthesis of oxindoles, ((IMes)Pd(NQ))2 can be used as an alternative to Pd2(dba)3 to catalyze the carbene CArsp2-H insertion, although it was less versatile. On the other hand, it was demonstrated that the Csp3-H insertion leading to ß-lactams can be effectively promoted by both Pd(0) and Pd(II) catalysts, the latter being most efficient. Insight into the reaction mechanisms involved in these transformations was provided by DFT calculations.

Palladium-catalysed intramolecular carbenoid insertion of α-diazo-α-(methoxycarbonyl)acetanilides for oxindole synthesis.

A novel, selective palladium-catalysed carbenoid C(aryl)-H insertion of α-diazo-α-(methoxycarbonyl)acetanilides leading to oxindoles is described.

Pd(0)-catalyzed intramolecular α-arylation of sulfones: domino reactions in the synthesis of functionalized tetrahydroisoquinolines.

A new strategy for the synthesis of tetrahydroisoquinolines based on the Pd(0)-catalyzed intramolecular α-arylation of sulfones is reported. The combination of this Pd-catalyzed reaction with intermolecular Michael and aza-Michael reactions allows the development of two- and three-step domino processes to synthesize diversely functionalized scaffolds from readily available starting materials.