Organozinc Catalyst on a Phenalenyl Scaffold for Intramolecular Hydroamination of Aminoalkenes

Abstract

The syntheses and characterization of two organozinc compounds were accomplished by reacting phenalenyl (PLY)-based ligands with ZnMe2. Reactions of [HN(Cy),O-PLY] and [HN(Cy),N(Cy)-PLY] ligands with ZnMe2 led to the formation of the dimeric orange-colored organozinc compound [N(Cy),O-PLY-ZnMe]2 (1) and red-colored monomeric organozinc compound [N(Cy),N(Cy)-PLY-ZnMe] (2) under evolution of methane. Both 1 and 2 were characterized by NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction study. The organozinc compound 2 was tested as a catalyst for intramolecular hydroamination of both unactivated primary and secondary aminoalkenes in the presence of an externally added activator, which generated the zinc-based cation in situ. The catalytic result obtained from the present catalyst 2 was compared with the catalysts having similar structure from previous studies. The DFT calculation indicates that the stability of the in situ generated cation plays a significant role in the catalytic activity in the hydroamination reaction.