Defluorinative 1,3‐Dienylation of Fluoroalkyl N‐Triftosylhydrazones with Homoallenols.

A silver‐catalyzed regioselective defluorinative 1,3‐dienylation of trifluoromethyl phenyl N‐triftosylhydrazones using homoallenols as 1,3‐dienyl sources provides a variety of α‐(di)fluoro‐β‐vinyl allyl ketones with excellent functional group tolerance in moderate to good yields. The reaction proceeds through a silver carbene‐initiated sequential etherification and Claisen type [3,3]‐sigmatropic rearrangement cascade. The synthetic utility of this protocol was demonstrated through the downstream synthetic elaboration toward diverse synthetically useful building blocks. [ABSTRACT FROM AUTHOR]