4,4,5,5-tetramethyl-2-(2-methylphenyl)-1,3,2-dioxaborolane

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 32.3 g (148 mmol) of 4,4,5,5-tetramethyl-2-(2-methylphenyl)-1,3,2-dioxaborolane, 25.0 g (141 mmol) of N-bromosuccinimide, and 0.32 g (2.62 mmol) of AIBN was refluxed in 1000 ml of acetonitrile for 2 h. The mixture was then cooled to room temperature and then evaporated to dryness. The residue was dissolved in 500 ml of hexane. The formed precipitate was filtered on glass frit (G3), and the filtrate was evaporated to dryness to give yellowish crystalline powder. Yield 28.9 g (66%). Anal. calc. for C13H18BBrO2: C, 52.57; H, 6.11. Found: C, 52.63; H, 6.29. 1H NMR (CDCl3): 7.81 (m, 1H, 6-H), 7.37-7.42 (m, 2H, 3, 5-H), 7.28 (m, 1H, 4-H), 4.91 (s, 2H, CH2Br), 1.37 (s, 1H, Bpin). evaporated to dryness The residue was dissolved in 500 ml of hexane The formed precipitate was filtered on glass frit (G3) the filtrate was evaporated to dryness to give yellowish crystalline powder

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 32.3 g (148 mmol) of 4,4,5,5-tetramethyl-2-(2-methylphenyl)-1,3,2-dioxaborolane, 25.0 g (141 mmol) of N-bromosuccinimide, and 0.32 g (2.62 mmol) of AIBN was refluxed in 1000 ml of acetonitrile for 2 h. The mixture was then cooled to room temperature and then evaporated to dryness. The residue was dissolved in 500 ml of hexane. The formed precipitate was filtered on glass frit (G3), and the filtrate was evaporated to dryness to give yellowish crystalline powder. Yield 28.9 g (66%). Anal. calc. for C13H18BBrO2: C, 52.57; H, 6.11. Found: C, 52.63; H, 6.29. 1H NMR (CDCl3): 7.81 (m, 1H, 6-H), 7.37-7.42 (m, 2H, 3, 5-H), 7.28 (m, 1H, 4-H), 4.91 (s, 2H, CH2Br), 1.37 (s, 1H, Bpin). evaporated to dryness The residue was dissolved in 500 ml of hexane The formed precipitate was filtered on glass frit (G3) the filtrate was evaporated to dryness to give yellowish crystalline powder

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 200 ml (0.21 mol) of 1.07 M solution of 2-methyl phenylmagnesiumbromide in THF, 49.3 g (0.27 mmol) of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was added at room temperature. The resulting solution was stirred for 15 min at the same temperature, and then 50 ml of water was added. The formed mixture was poured into 500 ml of water, and crude product was extracted with 3×200 ml of ethyl acetate. The combined organic extract was dried over Na2SO4 and then evaporated to dryness. Fractional distillation of the residue in vacuum gave colorless oil, b.p. 81-84° C./3 mmm Hg. Yield 33.1 g (57%). Anal. calc. for C13H19BO2: C, 71.59; H, 8.78. Found: C, 71.78; H, 8.65. 1H NMR (CDCl3): 7.78 (m, 1H, 6-H), 7.33 (m, 1H, 5-H), 7.16-7.19 (m, 2H, 3, 4-H), 2.56 (s, 3H, Me in 2-MeC6H4), 1.36 (s, 12H, Bpin). was extracted with 3×200 ml of ethyl acetate The combined organic extract was dried over Na2SO4 evaporated to dryness Fractional distillation of the residue in vacuum gave colorless oil, b.p. 81-84° C./3 mmm Hg

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 32.3 g (148 mmol) of 4,4,5,5-tetramethyl-2-(2-methylphenyl)-1,3,2-dioxaborolane, 25.0 g (141 mmol) of N-bromosuccinimide, and 0.32 g (2.62 mmol) of AIBN was refluxed in 1000 ml of acetonitrile for 2 h. The mixture was then cooled to room temperature and then evaporated to dryness. The residue was dissolved in 500 ml of hexane. The formed precipitate was filtered on glass frit (G3), and the filtrate was evaporated to dryness to give yellowish crystalline powder. Yield 28.9 g (66%). Anal. calc. for C13H18BBrO2: C, 52.57; H, 6.11. Found: C, 52.63; H, 6.29. 1H NMR (CDCl3): 7.81 (m, 1H, 6-H), 7.37-7.42 (m, 2H, 3, 5-H), 7.28 (m, 1H, 4-H), 4.91 (s, 2H, CH2Br), 1.37 (s, 1H, Bpin). evaporated to dryness The residue was dissolved in 500 ml of hexane The formed precipitate was filtered on glass frit (G3) the filtrate was evaporated to dryness to give yellowish crystalline powder

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 200 ml (0.21 mol) of 1.07 M solution of 2-methyl phenylmagnesiumbromide in THF, 49.3 g (0.27 mmol) of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was added at room temperature. The resulting solution was stirred for 15 min at the same temperature, and then 50 ml of water was added. The formed mixture was poured into 500 ml of water, and crude product was extracted with 3×200 ml of ethyl acetate. The combined organic extract was dried over Na2SO4 and then evaporated to dryness. Fractional distillation of the residue in vacuum gave colorless oil, b.p. 81-84° C./3 mmm Hg. Yield 33.1 g (57%). Anal. calc. for C13H19BO2: C, 71.59; H, 8.78. Found: C, 71.78; H, 8.65. 1H NMR (CDCl3): 7.78 (m, 1H, 6-H), 7.33 (m, 1H, 5-H), 7.16-7.19 (m, 2H, 3, 4-H), 2.56 (s, 3H, Me in 2-MeC6H4), 1.36 (s, 12H, Bpin). was extracted with 3×200 ml of ethyl acetate The combined organic extract was dried over Na2SO4 evaporated to dryness Fractional distillation of the residue in vacuum gave colorless oil, b.p. 81-84° C./3 mmm Hg