Gold-catalyzed cycloisomerization reactions of boronated enynes

Gold (I) complexes generated from a mixture of gold and silver salts were found to be highly reactive for the cycloisomerization reactions of boronated enynes. Both alkynyl pinacol boronates and alkenyl pinacol boronates were tolerated, affording products in moderate to high yields. Interestingly, the ratio of the different endo- and exo-products was heavily dependent on the position of the boronate functionality. Further applications including Suzuki–Miyaura cross coupling and oxidation reactions could be carried out, affording a variety of synthetically useful products.