Palladium-catalyzed asymmetric dearomative (3+2) annulation toward skeletally diverse spirocyclohexadienones

A palladium-catalyzed intermolecular asymmetric double allylic substitution enabling a dearomative (3+2) annulation reaction of 4-indolylphenols with butene dicarbonate is described. This transformation provides a diverse array of spirocyclohexadienone derivatives in good yields (up to 88%) and high enantioselectivity (up to >99% ee). When 4-indolylphenols bearing a C3-substituent on the indole ring were employed, the dearomative annulation proceeds through a distinct regioselective manifold, efficiently furnishing enantioenriched aza-spirocyclohexadienones with good yields.