Copper‐Catalyzed Cyclization–Fragmentations of Enynols

Abstract

Pt and Au are going out of fashion: The [Cu(CH3CN)4][BF4] species effectively catalyzes the cyclization–fragmentation of 5-en-1-yn-3-ols. The reactivity of 6-en-1-yn-4-ols greatly depends on the catalyst used (see scheme). An unusual fragmentation and metathesis reactions of 6-en-1-yn-4-ols have also been detected.