On the mechanism of the digold(I) hydroxide-catalyzed hydrophenoxylation of alkynes

Gomez-Suarez, Adrian and Oonishi, Yoshihiro and Martin, Anthony R. and Vummaleti, Sai V. C. and Nelson, David J. and Cordes, David B. and Slawin, Alexandra M. Z. and Cavallo, Luigi and Nolan, Steven P. and Poater, Albert (2016) On the mechanism of the digold(I) hydroxide-catalyzed hydrophenoxylation of alkynes. Chemistry - A European Journal, 22 (3). pp. 1125-1132. ISSN 0947-6539

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    Abstract

    Herein we present a detailed investigation of the mechanistic aspects of the dual gold-catalysed hydrophenoxylation of alkynes, using both experimental and computational methods. The dissociation of [{Au(NHC)}2(µ-OH)][BF4] is essential to enter the catalytic cycle; this step is favored in the presence of bulky, non-coordinating counterions. Moreover, in silico studies confirmed that phenol does not only act as a reactant, but as a co-catalyst, lowering the energy barriers for 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’ intermediate.