(4-溴-2,6-二甲基苯基)硼酸

反应条件: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a mixture of lead tetraacetate (112.16 g, 0.25 mol) and mercuric diacetate (4.8 g, 0.015 mol), thoroughly flushed with nitrogen, is added anhydrous chloroform (480 ml). This mixture is warmed to 40° C. and 4-bromo-2,6-dimethylphenylboronic acid (48 g, 0.21 mol) is added in one portion and the mixture is stirred and heated at this temperature for 4 hours. After cooling in an ice bath, powdered anhydrous potassium carbonate (350 g) is added rapidly followed by rapid stirring for 5 minutes. The solids are removed by filtration and the filtrate is concentrated to approximately a quarter of its volume. Hexane is added to induce crystallization and the solvents evaporated under reduced pressure. Trituration with hexane gives 4-bromo-2,6-dimethylphenyl lead triacetate (30 g). thoroughly flushed with nitrogen is added anhydrous chloroform (480 ml) heated at this temperature for 4 hours After cooling in an ice bath is added rapidly by rapid stirring for 5 minutes The solids are removed by filtration the filtrate is concentrated to approximately a quarter of its volume Hexane is added crystallization the solvents evaporated under reduced pressure

反应条件: temp:-75.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 4-bromo-2,6-dimethyl-1-iodobenzene (150 g, 0.48 mol) in tetrahydrofuran (1500 ml) at −75° C. is added n-butyl lithium (1.6 M in hexanes, 364 ml, 0.58 mol) dropwise maintaining the temperature of the reaction mixture below −70° C. When the addition is complete the mixture is stirred at −75° C. for an additional 30 minutes and then trimethyl borate (302 g, 2.9 mol) is added dropwise. After the addition is complete the reaction is stirred at −75° C. for 1 hour, then allowed to come to room temperature and stirred for 2 hours, followed by cooling in an ice bath and acidification with 0.5 N aqueous hydrochloric acid. The mixture is extracted with ethyl acetate (3×1000 ml) and the organic extracts are combined, washed with brine, dried over anhydrous sodium sulphate. The mixture is filtered and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-bromo-2,6-dimethylphenylboronic acid (48 g) as a white solid. dropwise maintaining the temperature of the reaction mixture below −70° C When the addition After the addition is stirred at −75° C. for 1 hour to come to room temperature stirred for 2 hours by cooling in an ice bath The mixture is extracted with ethyl acetate (3×1000 ml) washed with brine dried over anhydrous sodium sulphate The mixture is filtered the filtrate is evaporated under reduced pressure The residue is purified by column chromatography on silica gel

反应条件: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a mixture of lead tetraacetate (112.16 g, 0.25 mol) and mercuric diacetate (4.8 g, 0.015 mol), thoroughly flushed with nitrogen, is added anhydrous chloroform (480 ml). This mixture is warmed to 40° C. and 4-bromo-2,6-dimethylphenylboronic acid (48 g, 0.21 mol) is added in one portion and the mixture is stirred and heated at this temperature for 4 hours. After cooling in an ice bath, powdered anhydrous potassium carbonate (350 g) is added rapidly followed by rapid stirring for 5 minutes. The solids are removed by filtration and the filtrate is concentrated to approximately a quarter of its volume. Hexane is added to induce crystallization and the solvents evaporated under reduced pressure. Trituration with hexane gives 4-bromo-2,6-dimethylphenyl lead triacetate (30 g). thoroughly flushed with nitrogen is added anhydrous chloroform (480 ml) heated at this temperature for 4 hours After cooling in an ice bath is added rapidly by rapid stirring for 5 minutes The solids are removed by filtration the filtrate is concentrated to approximately a quarter of its volume Hexane is added crystallization the solvents evaporated under reduced pressure

反应条件: temp:-75.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 4-bromo-2,6-dimethyl-1-iodobenzene (150 g, 0.48 mol) in tetrahydrofuran (1500 ml) at −75° C. is added n-butyl lithium (1.6 M in hexanes, 364 ml, 0.58 mol) dropwise maintaining the temperature of the reaction mixture below −70° C. When the addition is complete the mixture is stirred at −75° C. for an additional 30 minutes and then trimethyl borate (302 g, 2.9 mol) is added dropwise. After the addition is complete the reaction is stirred at −75° C. for 1 hour, then allowed to come to room temperature and stirred for 2 hours, followed by cooling in an ice bath and acidification with 0.5 N aqueous hydrochloric acid. The mixture is extracted with ethyl acetate (3×1000 ml) and the organic extracts are combined, washed with brine, dried over anhydrous sodium sulphate. The mixture is filtered and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-bromo-2,6-dimethylphenylboronic acid (48 g) as a white solid. dropwise maintaining the temperature of the reaction mixture below −70° C When the addition After the addition is stirred at −75° C. for 1 hour to come to room temperature stirred for 2 hours by cooling in an ice bath The mixture is extracted with ethyl acetate (3×1000 ml) washed with brine dried over anhydrous sodium sulphate The mixture is filtered the filtrate is evaporated under reduced pressure The residue is purified by column chromatography on silica gel

反应条件: temp:-75.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 4-bromo-2,6-dimethyl-1-iodobenzene (150 g, 0.48 mol) in tetrahydrofuran (1500 ml) at −75° C. is added n-butyl lithium (1.6 M in hexanes, 364 ml, 0.58 mol) dropwise maintaining the temperature of the reaction mixture below −70° C. When the addition is complete the mixture is stirred at −75° C. for an additional 30 minutes and then trimethyl borate (302 g, 2.9 mol) is added dropwise. After the addition is complete the reaction is stirred at −75° C. for 1 hour, then allowed to come to room temperature and stirred for 2 hours, followed by cooling in an ice bath and acidification with 0.5 N aqueous hydrochloric acid. The mixture is extracted with ethyl acetate (3×1000 ml) and the organic extracts are combined, washed with brine, dried over anhydrous sodium sulphate. The mixture is filtered and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-bromo-2,6-dimethylphenylboronic acid (48 g) as a white solid. dropwise maintaining the temperature of the reaction mixture below −70° C When the addition After the addition is stirred at −75° C. for 1 hour to come to room temperature stirred for 2 hours by cooling in an ice bath The mixture is extracted with ethyl acetate (3×1000 ml) washed with brine dried over anhydrous sodium sulphate The mixture is filtered the filtrate is evaporated under reduced pressure The residue is purified by column chromatography on silica gel

反应条件: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a mixture of lead tetraacetate (112.16 g, 0.25 mol) and mercuric diacetate (4.8 g, 0.015 mol), thoroughly flushed with nitrogen, is added anhydrous chloroform (480 ml). This mixture is warmed to 40° C. and 4-bromo-2,6-dimethylphenylboronic acid (48 g, 0.21 mol) is added in one portion and the mixture is stirred and heated at this temperature for 4 hours. After cooling in an ice bath, powdered anhydrous potassium carbonate (350 g) is added rapidly followed by rapid stirring for 5 minutes. The solids are removed by filtration and the filtrate is concentrated to approximately a quarter of its volume. Hexane is added to induce crystallization and the solvents evaporated under reduced pressure. Trituration with hexane gives 4-bromo-2,6-dimethylphenyl lead triacetate (30 g). thoroughly flushed with nitrogen is added anhydrous chloroform (480 ml) heated at this temperature for 4 hours After cooling in an ice bath is added rapidly by rapid stirring for 5 minutes The solids are removed by filtration the filtrate is concentrated to approximately a quarter of its volume Hexane is added crystallization the solvents evaporated under reduced pressure

反应条件: temp:-75.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of 4-bromo-2,6-dimethyl-1-iodobenzene (150 g, 0.48 mol) in tetrahydrofuran (1500 ml) at −75° C. is added n-butyl lithium (1.6 M in hexanes, 364 ml, 0.58 mol) dropwise maintaining the temperature of the reaction mixture below −70° C. When the addition is complete the mixture is stirred at −75° C. for an additional 30 minutes and then trimethyl borate (302 g, 2.9 mol) is added dropwise. After the addition is complete the reaction is stirred at −75° C. for 1 hour, then allowed to come to room temperature and stirred for 2 hours, followed by cooling in an ice bath and acidification with 0.5 N aqueous hydrochloric acid. The mixture is extracted with ethyl acetate (3×1000 ml) and the organic extracts are combined, washed with brine, dried over anhydrous sodium sulphate. The mixture is filtered and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-bromo-2,6-dimethylphenylboronic acid (48 g) as a white solid. dropwise maintaining the temperature of the reaction mixture below −70° C When the addition After the addition is stirred at −75° C. for 1 hour to come to room temperature stirred for 2 hours by cooling in an ice bath The mixture is extracted with ethyl acetate (3×1000 ml) washed with brine dried over anhydrous sodium sulphate The mixture is filtered the filtrate is evaporated under reduced pressure The residue is purified by column chromatography on silica gel