2,6-dibromo-9-methylidenexanthene

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: Referring to Scheme 10, methylmagnesium iodide (14.12 mL, 3 M in Et2O, 42.4 mmol) was added to a stirred solution of 2,6-dibromo-9H-xanthen-9-one (7-2) (10 g, 28.2 mmol) in THF (30 mL) at 0° C. The reaction mixture was allowed to warm up to rt and stirred for 2 h. The reaction mixture was cooled to 0° C. and quenched with saturated NH4Cl solution (250 mL) and stirred for 30 min. The volatiles were removed in vacuo. The residue was taken up in CHCl3 (200 mL), and the organic layer was separated and the aqueous phase was extracted with CHCl3 (2×200 mL) and combined organics was dried over MgSO4, filtered and solvents removed in vacuo to crude product (9.46 g). The crude reaction was taken up in EtOAc (200 mL) and AcOH was added (20 mL) and the reaction mixture was stirred at room temperature for 3 h, the volatiles removed in vacuo and the residue was precipitated from isohexanes to give 2,6-dibromo-9-methylene-9H-xanthene (9-1) (6.43 g, 64.7% yield). The reaction mixture was cooled to 0° C. quenched with saturated NH4Cl solution (250 mL) stirred for 30 min The volatiles were removed in vacuo the organic layer was separated the aqueous phase was extracted with CHCl3 (2×200 mL) combined organics was dried over MgSO4 filtered solvents removed in vacuo to crude product (9.46 g) The crude reaction the reaction mixture was stirred at room temperature for 3 h the volatiles removed in vacuo the residue was precipitated from 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 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)

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

Procedure: Referring to Scheme 10, methylmagnesium iodide (14.12 mL, 3 M in Et2O, 42.4 mmol) was added to a stirred solution of 2,6-dibromo-9H-xanthen-9-one (7-2) (10 g, 28.2 mmol) in THF (30 mL) at 0° C. The reaction mixture was allowed to warm up to rt and stirred for 2 h. The reaction mixture was cooled to 0° C. and quenched with saturated NH4Cl solution (250 mL) and stirred for 30 min. The volatiles were removed in vacuo. The residue was taken up in CHCl3 (200 mL), and the organic layer was separated and the aqueous phase was extracted with CHCl3 (2×200 mL) and combined organics was dried over MgSO4, filtered and solvents removed in vacuo to crude product (9.46 g). The crude reaction was taken up in EtOAc (200 mL) and AcOH was added (20 mL) and the reaction mixture was stirred at room temperature for 3 hrs, the volatiles removed in vacuo and the residue was precipitated from isohexanes to give 2,6-dibromo-9-methylene-9H-xanthene (9-1) (6.43 g, 64.7% yield). The reaction mixture was cooled to 0° C. quenched with saturated NH4Cl solution (250 mL) stirred for 30 min The volatiles were removed in vacuo the organic layer was separated the aqueous phase was extracted with CHCl3 (2×200 mL) combined organics was dried over MgSO4 filtered solvents removed in vacuo to crude product (9.46 g) The crude reaction the reaction mixture was stirred at room temperature for 3 hrs the volatiles removed in vacuo the residue was precipitated from isohexanes