3-bromofuran-2-carbaldehyde

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: 3-Bromofuran (8.99 mL, 100.0 mmol) is dissolved in DMF (8.5 mL), cooled to 0° C., treated dropwise with POCl3 (9.79 mL, 105.0 mmol), stirred for 1 h at RT and then heated to 80° C. for 2 h. The mixture is cooled to RT, poured over ice (1 kg) and neutralized to pH 9 with solid K2CO3. The mixture is stirred for 1 h, extracted with Et2O (3×500 mL), dried over K2CO3 and concentrated to a dark brown oil. The crude material is chromatographed over 600 g slurry-packed silica gel, eluting with 6% EtOAc/hexane (4 L), 8% EtOAc/hexane (2 L), 10% EtOAc/hexane (1 L), and finally 20% EtOAc/hexane. The appropriate fractions are combined and concentrated in vacuo to afford 14.22 g (81%) of 3-bromo-2-furaldehyde as a yellow oil. MS (EI) m/z: 174 (M+). 3-Bromo-2-furaldehyde (14.22 g, 81.3 mmol) is combined with ethylene glycol (6.55 mL, 117.4 mmol) and para-toluene sulfonic acid monohydrate (772 mg, 4.06 mmol) in benzene (200 mL) and heated to reflux with a Dean-Stark trap for 5 h. Additional ethylene glycol (1.64 mL, 29.41 mmol) and benzene (150 mL) are added and the solution is heated for an additional 2 h. The mixture is cooled to RT, treated with saturated NaHCO3 and stirred for 0.5 h. The layers are separated and the organics are dried over Na2SO4 and concentrated to a brown oil (18.8 g). The crude material is chromatographed over 700 g slurry-packed silica gel, eluting with 15% EtOAc/hexane. The appropriate fractions are combined and concentrated in vacuo to afford 16.45 g (92%) of 2-(3-bromo-2-furyl)-1,3-dioxolane as a yellow-orange oil. MS (EI) m/z: 218 (M+). heated to reflux with a Dean-Stark trap for 5 h the solution is heated for an additional 2 h The layers are separated the organics are dried over Na2SO4 concentrated to a brown oil (18.8 g) The crude material is chromatographed over 700 g slurry-packed silica gel eluting with 15% EtOAc/hexane concentrated in vacuo

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Prepare a mixture of 3-bromofuran-2-carbaldehyde (381 mg, 2.19 mmol), phenylboronic acid (534 mg, 4.38 mmol), and 2M potassium carbonate (3.28 mL, 6.57 mmol) in 1,2-dimethoxyethane (20 mL). Bubble nitrogen into this mixture for 20 minutes. Add Pd2(dba)3 (68 mg, 0.06 mmol) and PPh3 (68 mg, 0.26 mmol) and purge the mixture with nitrogen for an additional 10 minutes. Then heat the mixture to 80° C. After 24 hours, evaporate the solvent and redissolve the residue in ethyl acetate. Extract the aqueous phase with ethyl acetate (2×10 mL), wash the combined organic phases with brine (40 mL), dry (magnesium sulfate), filter and concentrate. Perform flash chromatography on silica gel eluting with 5:1 hex/ethyl acetate to afford 405 mg of the title compound as a white solid. MS: m/e=173 [MH+] Prepare After 24 hours evaporate the solvent redissolve the residue in ethyl acetate Extract the aqueous phase with ethyl acetate (2×10 mL) wash the combined organic phases with brine (40 mL) dry (magnesium sulfate) filter concentrate

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Prepare a mixture of 3-bromofuran-2-carbaldehyde (381 mg, 2.19 mmol), phenylboronic acid (534 mg, 4.38 mmol), and 2M potassium carbonate (3.28 mL, 6.57 mmol) in 1,2-dimethoxyethane (20 mL). Bubble nitrogen into this mixture for 20 minutes. Add Pd2(dba)3 (68 mg, 0.06 mmol) and PPh3 (68 mg, 0.26 mmol) and purge the mixture with nitrogen for an additional 10 minutes. Then heat the mixture to 80° C. After 24 hours, evaporate the solvent and redissolve the residue in ethyl acetate. Extract the aqueous phase with ethyl acetate (2×10 mL), wash the combined organic phases with brine (40 mL), dry (magnesium sulfate), filter and concentrate. Perform flash chromatography on silica gel eluting with 5:1 hex/ethyl acetate to afford 405 mg of the title compound as a white solid. MS: m/e=173 [MH+] Prepare After 24 hours evaporate the solvent redissolve the residue in ethyl acetate Extract the aqueous phase with ethyl acetate (2×10 mL) wash the combined organic phases with brine (40 mL) dry (magnesium sulfate) filter concentrate

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

Procedure: Reaction of 3-bromofuran-2-carboxaldehyde (4.71 g, 27 mmole from Example 5) with 1-octyne (3 g, 27 mmole) as described in Example 8 afforded 3.96 g (72%) of the title compound, as an oil, after chromatography on silica (DCM:Hexane 1:2), νmax (film) 2950, 2930, 2850, 2230, 1680, 1570, 1420, 1360, 1275, 890, 775 cm-1 ; δ(CDCl3) 0.92(3H, distorted t), 1.42(8H, complex m), 2.48(2H, t, J=6.5 Hz), 6.59(1H, d, J=3 Hz), 7.62(1H, d, J=3 Hz), 9.82(1H, s).

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

Procedure: Reaction of 3-bromofuran-2-carboxaldehyde (3.86 g, 21.5 mmole, from Example 5) with 1-tridecyne (6.7 g) as described in Example 1 afforded 2.28 g (39% of the title compound after chromatography with dichloromethane on silica. Recrystallisation from petroleum ether [bp 40°-60° C.] afforded material of mp 56°-57° C., νmax 3170, 3120, 2230, 1660, 1420, 1355, 1280 cm-1 ; δ(CDCl3) 0.84 (3H, distorted t, terminal CH3), 1.11-1.67 (18H, m, alkylene chain), 2.40 (2H, t, J 6.3 Hz, CH2C≡C), 6.47 (1H, d, J ca 2 Hz, C-4H), 7.51 (1H, d, J ca 2 Hz, C-5H), 9.71 (1H, s CHO).

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: To a solution of 3-bromofuran-2-carbaldehyde (1.5 g, 8.57 mmol) and pyrrolidine (1.42 mL, 17.14 mmol) and CH2Cl2 (30 mL) was added sodium triacetoxyborohydride (3.63 g, 17.14 mmol). The mixture was stirred at room temperature for 5 hours. The resulting mixture was diluted with EtOAc (300 mL) and the organic layer was washed with saturated NaHCO3 and brine then dried (Na2SO4), filtered and concentrated. The residue was purified by column chromatography (silica, 0-10% MeOH in CH2Cl2) to afford the sub-title compound (1.26 g, 65%). the organic layer was washed with saturated NaHCO3 and brine then dried (Na2SO4) filtered concentrated The residue was purified by column chromatography (silica, 0-10% MeOH in CH2Cl2)