Catalytic Hydroamination of Alkynes and Norbornene with Neutral and Cationic Tantalum Imido Complexes

Abstract

[reaction: see text] Several tantalum imido complexes have been synthesized and shown to efficiently catalyze the hydroamination of internal and terminal alkynes. An unusual hydroamination/hydroarylation reaction of norbornene catalyzed by a highly electrophilic cationic tantalum imido complex is also reported. Factors affecting catalyst activity and selectivity are discussed along with mechanistic insights gained from stoichiometric reactions.

Characterizing Metal Coordination Environments in Porous Organic Polymers: A Joint Density Functional Theory and Experimental Infrared Spectroscopy Study

“…[20] Tantalumamide and tantalum-imide complexes have found numerous uses as catalysts. Of these are, for example, hydroaminoalkylA C H T U N G T R E N N U N G ation [21][22][23][24][25][26][27][28] and hydroamination, [29][30][31] atomefficient processes, in which an a-amino CÀH and an NÀH unit, respectively, are added across an unsaturated CÀC bond to give new amines of industrial or pharmaceutical interest. Other examples include use of tantalum-amide species as synthetic intermediates in formation of tantalum-hydride compounds in a metal-diolate ligand environment; [32] tantalum-hydride units supported by bulky aryloxide ligands, or on silica, which catalyze, respectively, homogeneous hydrogenation of arenes and heterogeneous metathesis of alkanes, including methane, as well as a suite of other related hydrocarbon transformations.…”

Synthesis and Properties of Oxygen‐Centered Tetradecaimido Hexatantalum Clusters

“…[7] Reaction mixtures often developed a red color during the course of the reaction, and catalyst deactivation was always observed within 24 hours regardless of the amount of 1 added (Scheme 1). A control experiment revealed that treatment of 1 with excess aniline at 135 8C resulted in the precipitation of a sparingly soluble, highly air-and moisturesensitive red crystalline material in low and erratic yield.…”

Thermooxidative degradation of methyl methacrylate‐graft‐natural rubber

“…The mixture was kept at 50 °C for 4 h. The resonances due to 8 along with those of ( p ‐tolyl)NC(Ph)(CH 2 Ph) were observed by 1 H NMR spectroscopy (100 % conversion). 1 H NMR (400 MHz , C 6 D 6 ): δ =8.06 (m, 2 H; aryl), 7.05 (m, 2 H; aryl), 6.97 (m, 4 H; aryl), 6.90 (m, 6 H; aryl), 3.91 (s, 2 H; C H 2 Ph), 2.10 ppm (s, 3 H; tolylC H 3 ) 26…”