Tunable Gold-catalyzed Reactions of Propargyl Alcohols and Aryl Nucleophiles

Abstract

Gold-catalyzed transformations of 1,3-diarylpropargyl alcohols and various aryl nucleophiles were studied. Selective tunable synthetic methods were developed for 1,1,3-triarylallenes, diaryl-indenes and tetraaryl-allyl target products by C3 nucleophilic substitution and subsequent intra- or intermolecular hydroarylation, respectively. The reactions were scoped with regards to gold(I)/(III) catalysts, solvent, temperature, and electronic and steric effects of both the diarylpropargyl alcohol and the aryl nucleophiles. High yields of triaryl-allenes and diaryl-indenes by gold(III) catalysis were observed. Depending on the choice of aryl nucleophile and control of reaction temperature, different product ratios have been obtained. Alternatively, tetraaryl-allyl target products were formed by a sequential one-pot tandem process from appropriate propargyl substrates and two different aryl nucleophiles. Corresponding halo-arylation products (I and Br; up to 95 % 2-halo-diaryl-indenes) were obtained in a one-pot manner in the presence of the respective N-halosuccinimides (NIS, NBS).