55402-07-8Relevant academic research and scientific papers
Selective Incorporation of Primary Amines into a Trizirconium Imido System and Catalyic Cyclization of Aminoalkynes
Oishi, Masataka,Nakanishi, Yusuke,Suzuki, Hiroharu
, p. 9802 - 9813 (2017)
The trinuclear zirconium imido complex [{LZr(NMe2)}3] (2, L = C5Me4CH2CH2N) was synthesized by amine elimination between Zr(NMe2)4 and endo-olefinic isomers of (tetramethylcyclopentadienyl)ethanamine (LH3) (1). To study the fundamental reactivity of the trizirconium system, reactions of 2 with primary amines were examined. Selective incorporations of the primary amines were observed, depending on steric and electronic natures of the amine substrates. The amine-incorporated complexes [(LZrNHR)(LHZrNHR)(LHZr)(μ-NHR)(μ3-NR)] (3, R = Pr, Et), [(LZrNHR)2(LHZr)(μ-NR)] (4, R = Pr, i-Bu), [(LZr)2(LZrNMe2)(μ-NR)] (5, R = neo-Pen), and [(LZr)(LZrNHAr)(LH2Zr)(μ-NAr)2] (6, Ar = Ph, C6H4-4-Br, C6H4-4-OMe) were structurally characterized by NMR and XRD analysis and showed several coordination modes of the substrate nitrogen ligands: i.e., terminal amides, bridging amides, and bridging imides but not terminal imides. Thermolysis of a mixture of 3 and 4 led to C-H bond activation, giving rise to the zirconaaziridines [{LZr(η2-NCHR)}(LZr)(LHZr)(μ-NHCH2R)] (12, R = Et, Me). Complex 2 proved to be a competent precatalyst in the hydroamination of the aminoalkynes (H2NCH2CR12CH2C=CR2) (13, R1 = H, R2 = Bu, Ph, t-Bu; 14, R1 = Me, R2 = Et, Ph). Stoichiometric or semicatalytic reactions of 2 and the aminoalkynes were studied to explore the reactivity of in situ formed Zr3 species.
