Isoprene hydroamination catalyzed by palladium xantphos complexes

Pd(II) Xantphos or Xantphos chalcogenide complexes with general folmula [PdCl2(X∩X)] (where X = P, O, S or Se) were synthesized by the addition of corresponding ligands to [PdCl2(COD)] (COD = 1,5-cyclooctadiene). Prepared Complexes [PdCl2(Xantphos)] and [PdCl2(Xantphos = S)] showed distorted square planar geometries, from X-ray crystallographic analysis. All of the prepared complexes showed activity toward intermolecular hydroamination of isoprene with a variety of secondary amines. Complete conversion (∼100%) of pyrrolidine was observed using Pd–Xantphos as catalysts. Hydroamination reactions exhibited regioselectivity when crowded secondary amines were used.

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► Pd–Xantphos complexes are potent isoprene hydroamination catalysts.
► An efficient synthesis of pharmaceutically important amines could be achieved.
► Amines with high steric hindrance yield 4-(3-methylbut-2-enyl) amines before reduction.