Transition Metal-Catalyzed Intermolecular Hydroarylation of Allenes

Abstract

The intermolecular transition-metal catalyzed hydroarylation of allenes has been widely explored since the early 1980s. This reaction allows the selective access to high-value allylic or vinylic motifs through the formation of C−C bonds. In this frame, arenes (ArH), which are employed without any pre-functionalisation, represent one of the most used families of aryl sources. Organoboronic derivatives (acids ArB(OH)2 and esters ArB(OR)2) constitute alternative, accessible and generally more reactive coupling partners, while aryl halides (ArX) are a third, less used type of aryl source. Whereas gold- and palladium-based catalysts are often used with arenes and aryl boronic derivatives, respectively, as aryl sources, a wide range of other transition metals have also been employed. Experimental and theoretical studies have often been reported, thus affording mechanistic insights and allowing to suggest catalytic cycles.