89% |
With bis-triphenylphosphine-palladium(II) chloride; 1,1',1"-[benzene-1,3,5-triyltris(methylene)]tris[(octyl)-4-pyridin-4-ylpyridinium] hexafluorophosphate; tetrabutylammonium bis[(trifluoromethane)sulfonyl]imide In N,N-dimethyl-formamide at 60℃; Electrochemical reaction; |
V2+.D./Pd-Mediated Reductive Coupling of 4-Bromopropiophenone (4a).
General procedure: In an undivided cellequipped with a Zn sacrificial anode (1.5 x 1.0 cm2) and a Pt cathode (1.5 x 1.0 cm2) was placed a DMF(3 mL) solution of 4-bromopropiophenone (4a, 0.053 g, 0.25 mmol), 1 (0.14 g, 7.6 x 10-2 mmol),[Bu4N+][Tf2N-] (0.16 g, 0.30 mmol), and a catalytic amount of PdCl2(PPh3)2 (0.0086 g, 1.2 x 10-2 mmol).The solution was electrolyzed under constant current conditions (10 mA) at 60 C until 2 F/mol-4a ofelectricity was passed. The reaction mixture was poured into 5% aq. HCl (12 mL). The mixture wasextracted with AcOEt (10 mL x 3). The combined organic layer was washed successively with waterand brine, dried (Na2SO4), and concentrated under reduced pressure. The residue was purified bycolumn chromatography (SiO2, toluene/AcOEt = 10/1) to afford 4,4’-dipropanoylbiphenyl (5a, 0.030 g,0.11 mmol, 89%). |
87% |
With bis-triphenylphosphine-palladium(II) chloride; 1,1'-dioctyl-4,4'-bipyridinium bis(trifluimide); tetrabutylammonium bis[(trifluoromethane)sulfonyl]imide In 1-methyl-pyrrolidin-2-one at 60℃; Electrochemical reaction; |
A typical procedure of the electroreductive coupling of aryl bromide1 with catalytic amounts of [OctV2+][Tf2N]2 and Pd species isas follows. Into an undivided cell fitted with a Zn anode(1.5 1 cm2) and a Pt cathode (1.5 1 cm2) was added a DMF(3 mL) solution of 4-bromopropiophenone (1a, 0.25 mmol),[Bu4N+][Tf2N] (0.3 mmol), [OctV2+][Tf2N]2 (0.075 mmol,30 mol %), and PdCl2(PPh3)2 (0.0125 mmol, 5 mol %). The wholemixture was electrolyzed at 60 C under constant current(10 mA) conditions until 2 F/mol-1a of electricity was passed.The reaction mixture was poured into 5% aq HCl and extractedwith AcOEt. Purification by column chromatography (SiO2, toluene/AcOEt = 10/1) afforded 4,40-dipropanoylbiphenyl (2a) in 94%yield |
82% |
With Tetrakis(dimethylamino)ethylen; 1-butyl-2,3-methylimidazolium tetrafluoroborate at 60℃; for 3h; |
|
78% |
With palladium diacetate; caesium carbonate; 1-indene In N,N-dimethyl-formamide at 20 - 90℃; for 24h; Inert atmosphere; Sealed tube; |
|
78% |
With palladium diacetate; caesium carbonate; 1-indene In N,N-dimethyl-formamide at 90℃; for 24h; Inert atmosphere; Sealed tube; |
|
71% |
With bis(benzonitrile)palladium(II) dichloride; 1,1'-dioctyl-1H,1'H-4,4'-bipyridinylidene In tetrahydrofuran for 20h; Electrochemical reaction; |
|
66% |
Stage #1: 3-cyanobromobenzene With n-butyllithium In tetrahydrofuran; hexane at 0℃; for 1.52778E-05h;
Stage #2: With iron(III) chloride In tetrahydrofuran; hexane at 0℃; for 0.000486111h;
Stage #3: With methanol In tetrahydrofuran; hexane at 0℃; for 0.000436111h; |
|
57% |
With tetrabutylammomium bromide; triethylamine; isopropyl alcohol In N,N-dimethyl-formamide at 115℃; for 23h; |
|
57% |
With triethylamine In N,N-dimethyl-formamide; isopropyl alcohol at 115℃; for 23h; |
|
51% |
With bis(bipyridine)nickel(II) bromide; ethylene dibromide; sodium iodide In N,N-dimethyl-formamide at 20℃; for 2h; Electrochemical reaction; Inert atmosphere; |
General procedure: DMF (40 mL), NaI (375 mg, 2.5 mmol), and 1,2-dibromoethane (100μL, 1.16 mmol) were added to an undivided electrochemical cell, fitted with an iron/nickel (64/36) anode, and surrounded by a nickel foam as the cathode (surface: 40 cm2, porosity: 500 μm, Goodfellow).The mixture was electrolyzed under argon at a constant current intensityof 0.2 A at r.t. for 15 min. The current was then stopped, then NiBr2bpy (187 mg, 0.5 mmol) and aryl or heteroaryl halide (5 mmol),were sequentially added. The solution was electrolyzed at 0.2 A untilthe starting aryl or heteroaryl halide had been totally consumed (2-5h). Sat. aq EDTA-Na2 solution (50 mL) was added, and the resultingsolution was extracted either with EtOAc (for aryl halides) or withCH2Cl2 (for heteroaryl halides) (3 × 50 mL). The combined organic layerswere washed with brine (50 mL), dried (MgSO4), filtered, and concentratedunder vacuum. The crude product was purified by flashchromatography (silica gel, 70-200 μm). |
43% |
Stage #1: 3-cyanobromobenzene With n-butyl magnesium bromide; n-butyllithium In tetrahydrofuran; hexane at -40℃; for 0.5h;
Stage #2: With titanium tetrachloride In tetrahydrofuran; hexane at -40℃; for 0.5h; |
|
18% |
With tetrakis(triphenylphosphine) palladium(0); bis(tri-n-butyltin) In toluene at 80℃; |
|
|
With n-butyllithium; Trimethyl borate; sodium carbonate 1) THF, -78 deg C -> room temperature, 4 h; room temperature, overnight, 2) THF, EtOH, H2O, toluene, reflux, 24 h; Yield given. Multistep reaction; |
|