Enantioselective N-Alkylation of Indoles via an Intermolecular Aza-Wacker-Type Reaction

The development of an intermolecular and enantioselective aza-Wacker reaction is described. Using indoles as the N-source and a selection of alkenols as the coupling partners selective beta-hydride elimination toward the alcohol was achieved. This strategy preserves the newly formed stereocenter by preventing the formation of traditionally observed enamine products. Allylic and homoallylic alcohols with a variety of functional groups are compatible with the reaction in high enantioselectivity. Isotopic-labeling experiments support a syn aminopalladation mechanism for this new class of aza-Wacker reactions.