Catalytic Cascade Access to Biaryl-2-Methyl Acetates from Pyruvate O-Arylmethyl Ketoximes via the Palladium-Catalyzed C(sp(2))H Bond Arylation and C-O Bond Solvolysis

摘要

A catalytic cascade has been developed for the synthesis of biaryl-2-methyl acetates via a palladium-catalyzed ortho-C(sp(2))-H bond arylation of pyruvate O-arylmethyl ketoximes with aryl iodides followed by a solvolysis, in which the pyruvic ketoxime ester as a new auxiliary is employed to direct the C(sp(2))-H bond activation. The straightforward treatment of O-arylmethyl hydroxylamines and ethyl pyruvate with aryl iodides also provides the target products in a one-pot fashion. Furthermore, the new palladacycle intermediate is unambiguously confirmed by single-crystal X-ray diffraction analysis. A plausible reaction pathway is proposed for the Pd-catalyzed arylation-acetolysis sequence.