Zn‐Catalyzed Cycloisomerization/Methylenation of Enyone with Vinyl Azide: Assembly of Terminal and Deuterated Alkenyl Furan Framework

An unprecedented zinc‐catalyzed cycloisomerization/methylenation reaction of enynone with vinyl azide is developed. Featuring inexpensive, less‐toxic catalyst, high efficiency, and mild reaction conditions, this protocol provides a practical synthetic method to access various bioactivity‐related terminal and deuterated alkenyl furans in up to 99% yield and 94% level of deuterium incorporation. The reaction is proposed to proceed through cycloisomerization, cyclopropanation, and ring fragmentation processes. Utility of this reaction is further demonstrated by transformation of the obtained molecules into selectively semi‐deuterated and non‐deuterated furan skeletons.