Palladium-Catalyzed C-H Arylation Using Aryltrifluoroborates in Conjunction with a Mn Oxidant under Mild Conditions.

This paper describes the development of a mild Pd-catalyzed C-H arylation reaction using potassium aryltrifluoroborates in conjunction with Mn(OAc) as the oxidant. The scope of this transformation is explored with a variety of different aryltrifluoroborates and arylpyridine substrates. Preliminary mechanistic studies suggest that the reaction proceeds via a high-valent Pd mechanism with C-H activation occurring at or before the rate determining step.

Mild palladium-catalyzed C-H alkylation using potassium alkyltrifluoroborates in combination with MnF3.

A Pd-catalyzed method for ligand-directed C-H alkylation with organoboron reagents is described. The combination of potassium organotrifluoroborates, MnF3, and a Pd(II) catalyst effects pyridine and amide-directed C-H alkylation. These reactions proceed under mild conditions (25-40 °C in weakly acidic media), are effective for installing methyl and 1° alkyl groups, and do not require promoters such as benzoquinone.