Transition Metal-Catalyzed Hydroarylation of Allenes
The transition metal-catalyzed addition of the C—H bond of an arene across a C=C double bond of an unactivated alkene (i.e., alkene hydroarylation) has attracted considerable attention as an atom-economical approach to the functionalization of arenes with potential application to both the large-scale alkylation of simple arenes and the synthesis of complex molecules. This chapter provides a review of the transition metal-catalyzed hydroarylation of allenes with electron-rich arenes. The scope of catalytic allene hydroarylation is expanded to include the exo- and endo- intramolecular hydroarylation and intermolecular hydroarylation of allenes employing a range of heteroaromatic and heteroatom-substituted arenes. The chapter then discloses several examples of enantioselective allene hydroarylation. Effective catalytic hydroarylation of allenes is dominated by π-activation processes involving the addition of nucleophilic, electron-rich arenes to allenes catalyzed by electrophilic and carbophilic late transition metal complexes, cationic gold(I) complexes in particular.
