On the Mechanism of the Digold(I)-Hydroxide-Catalysed Hydrophenoxylation of Alkynes

KGaA, Weinheim.Herein, we present a detailed investigation of the mechanistic aspects of the dual gold-catalysed hydrophenoxylation of alkynes by both experimental and computational methods. The dissociation of [{Au(NHC)}2(μ-OH)][BF4] is essential to enter the catalytic cycle, and this step is favoured by the presence of bulky, non-coordinating counter ions. Moreover, in silico studies confirmed that phenol does not only act as a reactant, but also as a co-catalyst, lowering the energy barriers of several transition states. A gem-diaurated species might form during the reaction, but this lies deep within a potential energy well, and is likely to be an "off-cycle" rather than an "in-cycle" intermediateA.P. thanks the Spanish MINECO (project CTQ2014-59832-JIN and FEDER grant UNGI10-4E-801 and the European Commission for a Career Integration Grant (CIG09-GA-2011-293900