On activation with catalytic amounts of gold(I) complexes, 3-silyloxy 1,6-enynes can react through two alternative pathways. In one, a cascade reaction consisting of carbocyclization and subsequent pinacol rearrangement takes place. In the second pathway, a heterocyclization is followed by a Claisen rearrangement. The reaction outcome differs depending on the substitution pattern of the 3-silyloxy 1,6-enynes and, more importantly, the electronic properties of the gold-bound phosphane ligand.

Golden reactivity: A new gold(I)‐catalyzed cycloisomerization of 3‐methoxy‐1,6‐enynes was discovered. Structurally simple 3‐methoxy‐1,6‐enynes engage in a tandem cyclization/[3,3]‐sigmatropic rearrangement to deliver a variety of 1‐methoxy‐1,4‐cycloheptadienes (see scheme). Notably, the reaction can be performed under very mild conditions and the synthetic utility of this reaction was demonstrated by facile conversion of the product into various cyclohept‐4‐en‐1‐ones.

Gold schließt den Ring: Eine neue Gold(I)‐katalysierte Cycloisomerisierung wandelt einfach aufgebaute 3‐Methoxy‐1,6‐enine durch eine Cyclisierung und [3,3]‐sigmatrope Umlagerung in 1‐Methoxy‐1,4‐cycloheptadiene um (siehe Schema). Die Reaktion läuft unter milden Bedingungen ab, und die Produkte können leicht zu Cyclohept‐4‐en‐1‐onen umgesetzt werden.

The Au(I)-catalyzed reactions of 5-allyloxy-1-ynes gave various γ-hydroxyketones, via a hydration-terminated domino sequence involving sigmatropic allyl migration as the key event. Moreover, the scope of the sigmatropic allyl transfer was systematically determined.