Metal-free β,γ-C(sp 3 )-H difunctionalization of propanols: DMP-initiated asymmetric spirocyclopropanation.

A DMP-initiated metal-free effective β,γ-asymmetric spirocyclopropanation of propanols strategy using oxidative iminium activation is described. This process has been realized by a synergistic amine-catalyzed one-pot cascade oxidation-Michael addition cyclopropanation for "one-pot" access to various spirocyclopropyl propionaldehydes/propanols from diverse 3-arylpropanols and α-brominated active methylene compounds under mild conditions and with high enantioselectivity (ee up to >99%).