Synthesis of the acutumine spirocycle via a radical-polar crossover reaction.

A new radical-polar crossover reaction was developed that consists of intramolecular conjugate addition of an aryl radical followed by enolate formation and hydroxylation. A C-C bond, a C-O bond, and two congested stereocenters are created in the process. The product is obtained as a single isomer. The method was used to synthesize the spirocyclic subunit of the alkaloid acutumine.