Rapid Assembly of Spiroisoxazolidines by [4+1] Dearomative Spiroannulation of ?-Bromo-?-naphthol and Nitroolefin

A novel [4 + 1] dearomative spiroannulation of alpha- halo-beta-naphthol and nitroolefin has been developed for the direct construction of various spiroisoxazolidines in high chemo-and diastereoselectivity. Notably, halophenols (X = Cl and I) were also tolerated by this reaction. This transformation was realized through a sequence of electrophilic dearomatization/dehalogenation, and mechanistic studies revealed that different routes occurred for C(sp3)-X bond cleavage. Moreover, the potential application of this method was exemplified by several further transformations.