Air-Stable Cationic Gold(I) Catalyst Featuring a Z-Type Ligand: Promoting Enyne Cyclizations

An air-stable cationic Au-I complex featuring a Z-type ligand (boron atom) as a s-acceptor was developed for elucidating the effect of B on catalytic reactions. An enyne cyclization in the presence of either [Au -> B](+) or [Au](+) showed that [Au -> B](+) promotes the reactivity, which enabled the effective construction of not only five-and six-membered rings, but also seven-membered rings.