dimethyl [1,1'-biphenyl]-2,4'-dicarboxylate

Synthesis

General procedure: synthesis of diethyl [1,1'-biphenyl]-2,4'-dicarboxylate via NiIICl(1-naphthalenyl)(PCy3)2 / PCy3-catalyzed cross-coupling reaction using methyl 4-(5,5-dimethyl-1,3,2-dioxaborole-2-yl)benzoate and benzoic acid,2-[(methanesulfonyl)oxy]-,methyl ester as raw materials. The reaction is applicable to both electron-rich and electron-deficient aryl halides and aryl methanesulfonates with neighboring, meso- and para-substitutions. Procedure: in a pre oven-dried test tube fitted with a polytetrafluoroethylene stir bar, aryl halides or aryl methanesulfonates (0.3 mmol), aryl neopentyl-propanedioate (0.315 mmol), K3PO4-3.2H2O (191.00±1.00 mg, 0.9 mmol), and NiIICl(1-naphthalenyl) (PCy3 ) 2 (11.73 ± 0.0510 mg, 0.015 mmol, 5% catalyst loading). The tubes were placed in a nitrogen atmosphere (moisture content <2 ppm) through three degassing cycles, followed by the addition of PCy3 (8.4 mg, 0.03 mmol, 10% loading) ligand. Distilled THF (1 mL) was added in a glove box, the test tube was sealed with a rubber septum, and the reaction was stirred at 23 °C. During the reaction, samples were taken via syringe and transferred outside the glove box for analysis. The sample was diluted with distilled THF (0.2 mL), filtered through an alumina short column, and the filtrate was concentrated for GC analysis. Upon completion of the reaction, the reaction mixture was diluted with CH2Cl2 (2 mL), filtered through an alumina layer, and washed with CH2Cl2 (31 mL). The filtrate was collected and concentrated in vacuum. The crude product was purified by silica gel column chromatography using EtOAc/hexane solvent mixture as eluent. The reduction-elimination by-products were also isolated and characterized.

References

[1] Journal of Organic Chemistry, 2012, vol. 77, # 6, p. 2885 - 2892
[2] Synthesis (Germany), 2016, vol. 48, # 17, p. 2795 - 2807
[3] Journal of Organic Chemistry, 2011, vol. 76, # 24, p. 9946 - 9955