3-Halotetrahydropyran-4-one Derivatives from Homopropargyl Acetal

Tunable Gold-catalyzed Reactions of Propargyl Alcohols and Aryl Nucleophiles

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).