Recent Progress on Gold-catalyzed Dearomatization Reactions

Homogeneous gold catalysis has experienced rapid development since 2004 and generally exhibited high efficiency and good functional group tolerance. On the other hand, catalytic dearomatization reactions provide a unique and straight approach to the construction of highly functionalized molecules with diverse three-dimensional structures from simple aromatic compounds. In this perspective, recent examples on gold-catalyzed dearomatization reactions are summarized in two main categories: gold-catalyzed rearrangements and gold-catalyzed hydrofunctionalizations of alkynes and allenes. In the first category, intra-and inter-molecular dearomatization reactions were achieved via gold-catalyzed rearrangements of propargylic ester and its derivatives. Although this area is still at its early stage, several outstanding asymmetric examples have been reported by Shi and Toste. In the second category, an array of dearomatization reactions via gold-catalyzed hydrofunctionalizations of alkynes and allenes were presented. All these cases have shown great potentials for convenient and straightforward construction of spiro and/or bridged polycyclic molecules, and some of them have exhibited excellent enantioselectivity. In addition, salient features and proposed mechanisms for these two types of reactions are also described.