Enantioselective Synthesis of Spiroimines by Asymmetric Decarboxylative Alkylation/Isomerization/[3+2]-Cycloaddition Reaction of Azidoalkenes

The synthesis of chiral spiroimines, one of the pharmacophores of the marine neurotoxin gymnodimine A is described. The approach relies on a three-step sequence that includes a palladium-catalyzed asymmetric decarboxylative alkylation, an isomerization and a [3+2]-cycloaddition reaction of an azidoalkene to build the imine.