C−C Bond Formation via C−H Bond Activation: Catalytic Arylation and Alkenylation of Alkane Segments

Abstract

A new system for catalytic arylation and alkenylation of alkane segments has been developed. The ortho-tert-butylaniline substrates and 2-pivaloylpyridine may be arylated and alkenylated at the tert-butyl group, while no functionalization occurred at more reactive C−H and other bonds. Arylation and alkenylation of these substrates are achieved in the presence of Ph₂Si(OH)Me and Ph−CHCH−Si(OH)Me₂, respectively, and the catalytic amount of Pd(OAc)₂ and stoichiometric oxidant (Cu(OAc)₂, 2 equiv) in DMF. In contrast, the ortho-i-propylaniline substrate underwent cyclopalladation, but no arylation product was obtained. Complex compound 14 was synthesized via tandem arylation-alkenylation of tert-butylaniline 11. We hypothesize that the high selectivity of this system stems from the confluence of directing effect of the Schiff base or pyridine moiety and unique reactivity properties of a phenyl-palladium acetate species (Ph-Pd-OAc·L_n).