Carboxylic Acid-Directed Manganese(I)-Catalyzed Regioselective Hydroarylation of Unactivated Alkenes.

A carboxylic acid-directed regioselective hydroarylation reaction of unactivated alkenes with aryl boronic acids was reported. This transformation was enabled by homogeneous manganese catalyst MnBr(CO) 5 in the presence of KOH and H 2 O in the m -xylene reaction medium. Both internal and terminal alkenes worked well in this transformation, and a series of functional groups were tolerated. This reaction not only provided an expeditious method to prepare γ-aryl carboxylic acids from simple starting materials but also would inspire further studies in employing homogeneous manganese catalysis in organic synthesis.