Tandem asymmetric dearomatized functionalization reaction of phenols with Evans-ynamides enabled by divergent electrophiles

Herein, we disclose a highly regio-/chemoselective tandem asymmetric dearomatized halofunctionalization reaction of phenol-tethered ynamides with diverse electrophilic halogenation sources in a catalyst-free manner for the practical and rapid assembly of a series of halogenated spirocyclic enones. Besides, the related dearomatized selenation and protonation are also achieved, affording the corresponding selenated and protonated spirocycles in high efficiency. Moreover, the enantioselectivities of these products can be perfectly induced by Evans auxiliaries (99% ees). Significantly, this protocol not only represents the first tandem asymmetric halofunctionalization reaction of phenol derivatives, but also constitutes the first asymmetric halogenation/selenation of ynamides. Theoretical calculations indicate a remote induction model of Evans chiral auxiliary-attached keteniminium.