Aminotroponate Zinc Complexes as Catalysts for the Intramolecular Hydroamination of Alkenes and Alkynes

The dimeric complexes 2-(isopropylamino)troponate zinc methyl and ethyl [(iPrAT)Zn-R]2 (R = Me
(2a), Et (2b)) were synthesized by reaction of (iPrAT)H with dimethyl and diethyl zinc, respectively, in
toluene at low temperature. Reacting (iPrAT)H with dimethyl zinc at elevated temperature resulted in
the double-substituted complex [(iPrAT)2Zn] (3). Compounds 2a,b, which were investigated by single-crystal X-ray diffraction, are dimeric in the solid state. The metal centers are bridged asymmetrically by
two (μ)-oxygen atoms; thus a flat Zn−O−Zn‘−O‘ plane is observed. Compounds 2a,b were used as the
catalyst in the intramolecular hydroamination reaction of nonactivated terminal aminoolefins and one
aminoalkyne. Good catalytic activities at elevated temperature were observed.