1-hydroxy-3,4-dihydro-2,1-benzoxaborinine

Conditions: temp:-42.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 4.0 mL fuming HNO3 at −45° C. was added 3,4-dihydro-benzo[c][1,2]oxaborinin-1-ol (497 mg, 3.4 mmol) in small portions while maintaining the reaction temperature between −40 to −45° C. Once the addition was complete the resulting solution was allowed to stir at −45° C. for an additional 10 min before poured into crushed ice (20 g). The ice mixture was allowed to warm up to room temperature gradually and the precipitate was collected by filtration and washed with H2O to give 7-nitro-3,4-dihydro-benzo[c][1,2]oxaborinin-1-ol as a white powder. 1H NMR (acetone) δ: 8.51 (d, J=2.5 Hz, 1H), 8.24 (dd, J=8.3, 2.6 Hz, 1H), 7.75 (s, 1H), 7.50 (d, J=8.4 Hz, 1H), 4.19 (t, J=6.0 Hz, 2H), 3.07 (t, J=6.0 Hz, 2H). Amount obtained: 286 mg, 44% yield. Once the addition before poured to warm up to room temperature gradually the precipitate was collected by filtration washed with H2O

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

Procedure: To a solution of 2-[2-(2-bromo-phenyl)-ethoxy]-tetrahydro-pyran (1.0 g, 3.5 mmol, 1.0 eq.) in THF (20 mL) at −78° C. was slowly added BuLi (2.4 mL, 2.5 M solution in THF, 3.8 mmol, 1.1 eq.) under nitrogen atmosphere. Triisopropyl borate (1.2 mL, 5.25 mmol, 1.5 eq.) was then added and the mixture was allowed to warm to room temperature gradually and stirred overnight. After carefully adding HCl (10 mL, 6N), the yellowish solution was stirred at room temperature for another 1 h and then poured into a mixture of EtOAc (30 mL) and H2O (20 mL). The layers were separated and the aqueous phase was extracted with EtOAc (3×30 mL). Combined organic extracts was washed with H2O (50 mL), brine (50 mL), dried over MgSO4, filtered and the filtrate was concentrated under reduced pressure. The oily residue was applied to silica chromatography eluting with EtOAc/Heptanes (0:100 to 100:0) to give 3,4-dihydro-benzo[c][1,2]oxaborinin-1-ol as a light yellow solid. 1H NMR (acetone) δ: 7.73 (d, J=7.2 Hz, 1H), 7.33-7.39 (m, 1H), 7.15-7.26 (m, 3H), 4.10 (t, J=6.0 Hz, 2H), 2.88 (t, J=6.0 Hz, 2H). Amount obtained 497 mg, 95.9% yield. at −78° C. The layers were separated the aqueous phase was extracted with EtOAc (3×30 mL) Combined organic extracts was washed with H2O (50 mL), brine (50 mL) dried over MgSO4 filtered the filtrate was concentrated under reduced pressure eluting with EtOAc/Heptanes (0:100 to 100:0)

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

Procedure: To a solution of 2-[2-(2-bromo-phenyl)-ethoxy]-tetrahydro-pyran (1.0 g, 3.5 mmol, 1.0 eq.) in THF (20 mL) at −78° C. was slowly added BuLi (2.4 mL, 2.5 M solution in THF, 3.8 mmol, 1.1 eq.) under nitrogen atmosphere. Triisopropyl borate (1.2 mL, 5.25 mmol, 1.5 eq.) was then added and the mixture was allowed to warm to room temperature gradually and stirred overnight. After carefully adding HCl (10 mL, 6N), the yellowish solution was stirred at room temperature for another 1 h and then poured into a mixture of EtOAc (30 mL) and H2O (20 mL). The layers were separated and the aqueous phase was extracted with EtOAc (3×30 mL). Combined organic extracts was washed with H2O (50 mL), brine (50 mL), dried over MgSO4, filtered and the filtrate was concentrated under reduced pressure. The oily residue was applied to silica chromatography eluting with EtOAc/Heptanes (0:100 to 100:0) to give 3,4-dihydro-benzo[c][1,2]oxaborinin-1-ol as a light yellow solid. 1H NMR (acetone) δ: 7.73 (d, J=7.2 Hz, 1H), 7.33-7.39 (m, 1H), 7.15-7.26 (m, 3H), 4.10 (t, J=6.0 Hz, 2H), 2.88 (t, J=6.0 Hz, 2H). Amount obtained 497 mg, 95.9% yield. at −78° C. The layers were separated the aqueous phase was extracted with EtOAc (3×30 mL) Combined organic extracts was washed with H2O (50 mL), brine (50 mL) dried over MgSO4 filtered the filtrate was concentrated under reduced pressure eluting with EtOAc/Heptanes (0:100 to 100:0)

Conditions: temp:-42.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 4.0 mL fuming HNO3 at −45° C. was added 3,4-dihydro-benzo[c][1,2]oxaborinin-1-ol (497 mg, 3.4 mmol) in small portions while maintaining the reaction temperature between −40 to −45° C. Once the addition was complete the resulting solution was allowed to stir at −45° C. for an additional 10 min before poured into crushed ice (20 g). The ice mixture was allowed to warm up to room temperature gradually and the precipitate was collected by filtration and washed with H2O to give 7-nitro-3,4-dihydro-benzo[c][1,2]oxaborinin-1-ol as a white powder. 1H NMR (acetone) δ: 8.51 (d, J=2.5 Hz, 1H), 8.24 (dd, J=8.3, 2.6 Hz, 1H), 7.75 (s, 1H), 7.50 (d, J=8.4 Hz, 1H), 4.19 (t, J=6.0 Hz, 2H), 3.07 (t, J=6.0 Hz, 2H). Amount obtained: 286 mg, 44% yield. Once the addition before poured to warm up to room temperature gradually the precipitate was collected by filtration washed with H2O

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

Procedure: To a solution of 2-[2-(2-bromo-phenyl)-ethoxy]-tetrahydro-pyran (1.0 g, 3.5 mmol, 1.0 eq.) in THF (20 mL) at −78° C. was slowly added BuLi (2.4 mL, 2.5 M solution in THF, 3.8 mmol, 1.1 eq.) under nitrogen atmosphere. Triisopropyl borate (1.2 mL, 5.25 mmol, 1.5 eq.) was then added and the mixture was allowed to warm to room temperature gradually and stirred overnight. After carefully adding HCl (10 mL, 6N), the yellowish solution was stirred at room temperature for another 1 h and then poured into a mixture of EtOAc (30 mL) and H2O (20 mL). The layers were separated and the aqueous phase was extracted with EtOAc (3×30 mL). Combined organic extracts was washed with H2O (50 mL), brine (50 mL), dried over MgSO4, filtered and the filtrate was concentrated under reduced pressure. The oily residue was applied to silica chromatography eluting with EtOAc/Heptanes (0:100 to 100:0) to give 3,4-dihydro-benzo[c][1,2]oxaborinin-1-ol as a light yellow solid. 1H NMR (acetone) δ: 7.73 (d, J=7.2 Hz, 1H), 7.33-7.39 (m, 1H), 7.15-7.26 (m, 3H), 4.10 (t, J=6.0 Hz, 2H), 2.88 (t, J=6.0 Hz, 2H). Amount obtained 497 mg, 95.9% yield. at −78° C. The layers were separated the aqueous phase was extracted with EtOAc (3×30 mL) Combined organic extracts was washed with H2O (50 mL), brine (50 mL) dried over MgSO4 filtered the filtrate was concentrated under reduced pressure eluting with EtOAc/Heptanes (0:100 to 100:0)