Divergence between Organometallic and Single-Electron-Transfer Mechanisms in Copper(II)-Mediated Aerobic C-H Oxidation

作者：Suess, Alison M.; Ertem, Mehmed Z.^*; Cramer, Christopher J.; Stahl, Shannon S.

来源：Journal of the American Chemical Society, 2013, 135(26): 9797-9804.

DOI：10.1021/ja4026424

• METALATION-DEPROTONATION MECHANISM
• COPPER-CATALYZED OXIDATION
• N-CONFUSED PORPHYRIN
• BOND FORMATION
• AROMATIC-SUBSTITUTION
• TERMINAL ALKYNES
• DIRECT ARYLATION
• PALLADIUM
• ACTIVATION
• COMPLEXES

Copper(II)-mediated C-H oxidation is the subject of extensive interest in synthetic chemistry, but the mechanisms of many of these reactions are poorly understood. Here, we observe different products from Cu-II-mediated oxidation of N-(8-quinolinyl)benzamide, depending on the reaction conditions. Under basic conditions, the benzamide group undergoes directed C-H methoxylation or chlorination. Under acidic conditions, the quinoline group undergoes nondirected chlorination. Experimental and computational mechanistic studies implicate an organometallic C-H activation/functionalization mechanism under the former conditions and a single-electron-transfer mechanism under the latter conditions. This rare observation of divergent, condition-dependent mechanisms for oxidation of a single substrate provides a valuable foundation for understanding Cu-II-mediated C-H oxidation reactions.

• 出版日期2013-7-3