Rhodium-Catalyzed Decarbonylative Direct C2-Arylation of Indoles with Aryl Carboxylic Acids

A Rh-1-catalyzed direct C2-arylation of indoles with diversely substituted aryl carboxylic acids has been developed using 2-pyrimidyl group as an easily installable and readily removable N-directing group. The reaction proceeded smoothly without the need for any external oxidants under relatively mild conditions to produce the C2-arylated indoles in high yields with excellent regioselectivity. A range of functional groups in both coupling partners were tolerated regardless of their electronic properties and positions. With the assistance of the 2-pyrimidyl group, these C2-functionalized products could further undergo C7-arylation to give the C7-aryl indole products. Mechanistic evidence supports that the reaction involves a decarbonylation step, and the carboxylic acids could be activated in situ by treatment with (tBuCO)(2)O to generate the active anhydrides.Chemistry, PhysicalSCI(E)EI4ARTICLExulj@chem.ruc.edu.cn; hrli@ruc.edu.cn; zshi@pku.edu.cn113069-3074