Pd-Catalyzed Direct C-H Alkenylation and Allylation of Azine N-Oxides.

A Pd-catalyzed direct C2-alkenylation of azine N-oxides with allyl acetate is disclosed. The products are formed through an allylation/isomerization cascade process. The use of a tri- tert-butylphosphonium salt as the ligand precursor and KF is mandatory for optimal yields. When cinnamyl acetate is used, the same catalytic system promotes C2-cinnamylation of the azine N-oxide without subsequent isomerization. A mechanism is proposed on the basis of experimental studies and DFT calculations.