Palladium‐Catalyzed,Highly Efficient,Regiocontrolled Arylation of Electron‐Rich Allylamines with Aryl Halides

The highly efficient and regioselective palladium‐catalyzed Heck coupling of aryl bromides with electron‐rich allylamine derivatives is described. It was found that the choice of solvent, olefin, ligand and additive had a fundamental influence on the regioselectivity and reactivity of the reaction. The combination of palladium acetate Pd(OAc)₂] and 1,3‐bis(diphenylphosphino)propane (dppp) in ethylene glycol (EG) constitutes a highly effective catalyst system for internal arylation of N‐Boc‐allylamine (tert‐butyl methyl allyliminodicarbonate) with aryl bromides to give good to excellent regioselectivities, while the catalyst system consisting of Pd(OAc)₂, tetrabutylammonium bromide (TBAB) and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) additive allows for a variety of aryl bromides to react efficiently with N,N‐(Boc)₂‐allylamine (di‐tert‐butyl allyliminodicarbonate) in water to exclusively afford the linear (E)‐allylamine products in high yields.