Mechanistic investigation into the C(sp3)-H acetoxylation of morpholinones.

Abstract

The study of a selective palladium(ii)-catalyzed C(sp3)-H acetoxylation reaction on a class of cyclic alkyl amines is reported. Computational modelling and kinetic studies were used to provide support for a mechanism involving selective C-O bond formation from a γ-aminoalkyl-Pd(iv) intermediate. The C-O bond forming step was computed to occur by a dissociative ionization mechanism followed by an SN2 process involving external acetate attack at the C-Pd(iv) bond. This pathway was computed to be of lowest energy with no competing C-N products observed. Additionally, with a few modifications to reaction conditions, preliminary studies showed that this process could be rendered enantioselective in the presence of a non-racemic BINOL-phosphoric acid.