Ligand-Controlled α- and β-Arylation of Acyclic N-Boc Amines

The palladium‐catalyzed ligand‐controlled arylation of α‐zincated acyclic amines, obtained by directed α‐lithiation and transmetalation, is described. Whereas PtBu3 gave rise to α‐arylated Boc‐protected amines, more flexible N‐phenylazole‐based phosphine ligands induced major β‐arylation through migrative cross‐coupling. All manner of control: The arylation of α‐zincated acyclic Boc‐protected amines was selectively performed at the α‐ or β‐position in a ligand‐controlled manner. α‐Arylation occurs by direct reductive elimination of the α‐palladated intermediate whereas β‐arylation involves palladium migration along the alkyl chain. Boc=tert‐butoxycarbonyl.