Catalytic C–H Bond Alkylation of Azoles with Alkyl Halides Mediated by Nickel(II) Complexes of Phenanthridine-Based N^N^–^N Pincer Ligands

Abstract

Ni(II) complexes supported by tridentate N^N − ^N diarylamido pincer-type ligands have been demonstrated to act as active catalysts in the carbon−carbon bond forming alkylation of azoles using unactivated alkyl halides. Here, we show that benzannulated phenanthridine-containing ligands can form homogeneous Ni(II) catalysts active with both benzoxazole and benzothiazole substrates. These precatalysts have been fully characterized in solution and the solid state, including by cyclic voltammetry.

Pseudo-octahedral nickel(ii) complexes of strongly absorbing benzannulated pincer-type amido ligands: ligand-based redox and non-Aufbau electronic behaviour

“…Compared with quinoline and acridine, the coordination chemistry of phenanthridine-containing multidentate ligand scaffolds is much less developed. 28 We previously described the preparation of (4-amino)phenanthridines amenable for incorporation into multidentate ligands, including those bearing methyl, 16 tert -butyl ( t Bu; 1a) 19 and trifluoromethyl (1b) 29 substituents in the 2-position of the heterocycle. Here, we extend this methodology to include installation of a halide (Cl; 1c).…”

Deep-Red Luminescence from Platinum(II) Complexes of N^N–^N-Amido Ligands with Benzannulated N-Heterocyclic Donor Arms

“…Pd 2 (dba) 3 , Pd­(PPh 3 ) 4 , Pd­(OAc) 2 , (±)-2,2′- bis (diphenylphosphino)-1,1′-binaphthalene ( rac -BINAP), 1,1′-bis­(diphenylphosphino)­ferrocene (dppf), sodium tert -amoxide (NaO t Am), and sodium tert -butoxide (NaO t Bu) were purchased (Sigma-Aldrich) and used without further purification. 8-Bromo-6-methylquinoline, 8-amino-6-methylquinoline, 4-amino-2-trifluoromethylphenanthridine, Pt­(COD)­Cl 2 , 4-amino-2-methylphenanthridine, L1 Me,Me , L2 Me,Me , 1 Me,Me and 2 Me,Me , L3 Me,Me and 3 Me,Me , and L2 H , t Bu and L2 H,CF 3 were synthesized according to literature procedures. Organic solvents were dried and distilled using appropriate drying agents, and distilled water was degassed prior to use.…”

Nickel‐Catalyzed C−H Bond Functionalization of Azoles and Indoles

“…Recently, Herbert synthesized a phenanthridine‐based ( CF3−phen NNN Me2 )NiCl ( 6 ) complex and successfully employed it for the regioselective alkylation of benzoxazole (Scheme 3). [17] This catalyst system requires 140 °C and provided low to moderate yields of the desired alkylated products.…”