(2,6-dibromo-9H-xanthen-9-yl)methanol

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

Procedure: Phosphorus pentoxide (5.04 g, 35.5 mmol) was added portion-wisely to a stirred solution of (2,6-dibromo-9H-xanthen-9-yl)methanol (10-1) (1.01 g, 2.73 mmol) in toluene (100 mL) and the suspension was heated under reflux for 20 min. The mixture was allowed to cool to rt and toluene was removed by decantation. The residual solid was washed with toluene (2×100 mL) by further decantation. The combined organics were cooled in an ice bath and brine (400 mL) was added slowly. The layers were separated and the organic washed with water (300 mL), brine (300 mL), dried over MgSO4 and evaporated to dryness, to give a yellow oily solid. The product was purified by column chromatography (SiO2, 0-10% EtOAc/isohexanes) to give 2,7-dibromodibenzo[b,f]oxepine (10-2) (763 mg, 79% yield) as a clear oil. 1H NMR (CDCl3) δ 7.41-7.36 (1H, m), 7.33-7.31 (1H, m), 7.29-7.24 (2H, m), 7.04-6.99 (2H, m), 6.68-6.57 (2H, m) ppm. the suspension was heated under reflux for 20 min toluene was removed by decantation The residual solid was washed with toluene (2×100 mL) by further decantation The combined organics were cooled in an ice bath brine (400 mL) was added slowly The layers were separated the organic washed with water (300 mL), brine (300 mL) dried over MgSO4 evaporated to dryness to give a yellow oily solid The product was purified by column chromatography (SiO2, 0-10% EtOAc/isohexanes)

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

Procedure: Borane-THF complex (36.5 mL, 1M THF, 36.5 mmol) was added to a stirred solution of 2,6-dibromo-9-methylene-9H-xanthene (9-1) (6.43 g, 18.27 mmol) in THF (75 mL) at 0° C. The mixture was allowed to warm up to rt and stirred for 1 h. The reaction mixture was cooled to 0° C. and a mixture of hydrogen peroxide (35 wt % in water) (5.76 mL, 65.8 mmol) and NaOH (25.6 mL, 2 M aq, 51.1 mmol) was added cautiously. The mixture was allowed to warm up to rt over 30 min. The reaction mixture was then poured into water (200 mL) and extracted with DCM (3×150 mL). The combined organics were washed with water (2×200 mL), brine (200 mL), dried over MgSO4, filtered and volatiles removed in vacuo to give a yellow solid. The crude product was purified by column chromatography (SiO2, 0-100% EtOAc/isohexanes) to afford (2,6-dibromo-9H-xanthen-9-yl)methanol (10-1) (2.5 g, 37.0% yield) as a yellow solid. 1H NMR (CDCl3) δ 7.42-7.39 (1H, m), 7.37-7.35 (1H, m), 7.28-7.27 (1H, m), 7.25-7.21 (1H, m), 7.16-7.12 (1H, m), 7.00-6.97 (1H, m), 4.00 (1H, t, J=5.9 Hz), 1.46 (2H, d, J=5.9 Hz) ppm. The reaction mixture was cooled to 0° C. was added cautiously to warm up to rt over 30 min extracted with DCM (3×150 mL) The combined organics were washed with water (2×200 mL), brine (200 mL) dried over MgSO4 filtered volatiles removed in vacuo to give a yellow solid The crude product was purified by column chromatography (SiO2, 0-100% EtOAc/isohexanes)

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

Procedure: Phosphorus pentoxide (5.04 g, 35.5 mmol) was added portion-wisely to a stirred solution of (2,6-dibromo-9H-xanthen-9-yl)methanol (10-1) (1.01 g, 2.73 mmol) in toluene (100 mL) and the suspension was heated under reflux for 20 min. The mixture was allowed to cool to rt and toluene was removed by decantation. The residual solid was washed with toluene (2×100 mL) by further decantation. The combined organics were cooled in an ice bath and brine (400 mL) was added slowly. The layers were separated and the organic washed with water (300 mL), brine (300 mL), dried over anhydrous MgSO4 and evaporated to dryness, to give a yellow oily solid. The product was purified by column chromatography (SiO2, O-10% EtOAc/isohexanes) to give 2,7-dibromodibenzo[b,f]oxepine (10-2) (763 mg, 79% yield) as a clear oil. 1H NMR (CDCl3): δ 7.41-7.36 (1H, m), 7.33-7.31 (1H, m), 7.29-7.24 (2H, m), 7.04-6.99 (2H, m), 6.68-6.57 (2H, m) ppm. the suspension was heated under reflux for 20 min toluene was removed by decantation The residual solid was washed with toluene (2×100 mL) by further decantation The combined organics were cooled in an ice bath brine (400 mL) was added slowly The layers were separated the organic washed with water (300 mL), brine (300 mL) dried over anhydrous MgSO4 evaporated to dryness to give a yellow oily solid The product was purified by column chromatography (SiO2

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

Procedure: Borane-THF complex (36.5 mL, 1M THF, 36.5 mmol) was added to a stirred solution of 2,6-dibromo-9-methylene-9H-xanthene (9-1) (6.43 g, 18.27 mmol) in THF (75 mL) at 0° C. The mixture was allowed to warm up to rt and stirred for 1 h. The reaction mixture was cooled to 0° C. and a mixture of hydrogen peroxide (35 wt % in water) (5.76 mL, 65.8 mmol) and NaOH (25.6 mL, 2 M aq, 51.1 mmol) was added cautiously. The mixture was allowed to warm up to rt over 30 min. The reaction mixture was then poured into water (200 mL) and extracted with DCM (3×150 mL). The combined organics were washed with water (2×200 mL), brine (200 mL), dried over anhydrous MgSO4, filtered and volatiles removed in vacuo to give a yellow solid. The crude product was purified by column chromatography (SiO2, 0-100% (v/v) of EtOAc/isohexanes) to afford (2,6-dibromo-9H-xanthen-9-yl)methanol (10-1) (2.5 g, 37.0% yield) as a yellow solid. 1H NMR (CDCl3): δ 7.42-7.39 (1H, m), 7.37-7.35 (1H, m), 7.28-7.27 (1H, m), 7.25-7.21 (1H, m), 7.16-7.12 (1H, m), 7.00-6.97 (1H, m), 4.00 (1H, t, J=5.9 Hz), 1.46 (2H, d, J=5.9 Hz) ppm. The reaction mixture was cooled to 0° C. was added cautiously to warm up to rt over 30 min extracted with DCM (3×150 mL) The combined organics were washed with water (2×200 mL), brine (200 mL) dried over anhydrous MgSO4 filtered volatiles removed in vacuo to give a yellow solid The crude product was purified by column chromatography (SiO2, 0-100% (v/v) of EtOAc/isohexanes)