We herein report a novel copper-catalyzed asymmetric dearomative 4 + 1 spirocyclization of 3H-indoles with vinyl ethynylethylene carbonates. This transformation proceeds through a highly chemo-, regio-, and enantioselective nucleophilic addition/intramolecular annulation cascade of a reactive copper vinylallenylidene intermediate, delivering a series of valuable spiroindolenine derivatives featuring a chiral quaternary stereocenter with excellent efficiency.
Guo et al. (Fri,) studied this question.