Palladium-catalyzed amination of 1-bromo- and 1-chloro-1,3-butadienes:: A general method for the synthesis of 1-amino-1,3-butadienes

1-Amino-1,3-butadienes, interesting substrates for [4+2] cycloadditions, are prepared by Pd-catalyzed cross-coupling of secondary amines with readily available 1-halodienes. The optimized catalytic system employs Pd-2(dba)(3) as metal source and XPHOS as supporting ligand. The reaction proceeds in very high yields with 1-bromo-1,3-butadienes, and also with the less reactive 1-chloro-1,3butadienes. Moreover, the range of amines that can be incorporated includes aromatic amines, and cyclic and acyclic aliphatic amines.