Anovel palladium-catalyzed [4+ +1] spiroannulation was developed by using aC (sp 3 ) À Ha ctivation/naphthol dearomatization approach.This bimolecular domino reaction of two aryl halides was realized through as equence of cyclometallation-facilitated C(sp 3 )ÀHa ctivation, biaryl crosscoupling,a nd naphthol dearomatization, thus rendering the rapid assembly of anew class of spirocyclic molecules in good yields with broad functional-group tolerance.P reliminary mechanistic studies indicate that CÀHc leavage is likely involved in the rate-determining step,a nd af ive-membered palladacycle was identified as the key intermediate for the intermolecular coupling.Scheme 2. Catalytic processes involving electron-rich palladacycles.

Rapid assembly of fluorene-based spirocycles represents a highly significant but challenging task in organic synthesis. Reported herein is a novel Pd(0)-catalyzed [4+1] spiroannulation of simple o-iodobiaryls with bromonaphthols for the...