A regioselective synthesis of benzopinacolones through aerobic dehydrogenative α-arylation of the tertiary sp3 C-H bond of 1,1-diphenylketones with aromatic and heteroaromatic compounds

Abstract

A regioselective synthesis of symmetrical and unsymmetrical benzopinacolones through aerobic dehydrogenative α-arylation at the tertiary sp(3) C-H bond of substituted 1,1-diphenylketones with aromatic and heteroaromatic compounds, in the presence of K2S2O8 in CF3COOH at room temperature, is described. The reaction is proposed to go via a carbocation intermediate, which could be generated directly from cleavage of the sp(3) C-H bond of 1,1-diphenylketone. Subsequent α-arylation was achieved at the methene sp(3) carbon atom of the substituted ketone. A variety of substituted aromatic and heteroaromatic compounds were compatible with this reaction. In addition, benzopinacolones were converted into sterically hindered, tetrasubstituted alkenes and polycyclic aromatic compounds.

Keywords: CH activation; aromatic substitution; arylation; carbocations; radical reactions.