81% |
With 1,3-bis-(diphenylphosphino)propane; palladium diacetate; triethylamine; In dimethyl sulfoxide; at 80℃; under 3102.97 Torr; for 18.0h; |
A mixture of 130 (3.88 g, 14.6 mmol), DPPP (0.180 g, 0.44 mmol), triethylamine (4.07 mL, 29.2 mmol) and Pd(OAc)2 (0.098 g, 0.44 mmol) in DMSO (50 mL) and MeOH (50 mL) in a Berghof pressure reactor was evacuated then purged three times with carbon monoxide. The mixture was heated to 80 C for 18 h under 60 psi of carbon monoxide pressure, cooled and partitioned between EtOAc and water. Column chromatography with 3 : 1 hexanes:DCM eluted traces of impurities while elution with DCM gave 131 (2.08 g, 81%). 1H NMR (CDC13) delta 7.99 (dd, J = 7.7, 0.9 Hz, 1H), 7.74 (d, J = 2.2 Hz, 1H), 7.70 (dt, J = 8.2, 0.9 Hz, 1H), 7.33-7.39 (m, 2H), 3.99 (s, 3H). |
81% |
With 1,3-bis-(diphenylphosphino)propane; palladium diacetate; triethylamine; In dimethyl sulfoxide; at 80℃; under 3102.97 Torr; for 18.0h; |
A mixture of the above sulfonate (3.88 g, 14.6 mmol), DPPP(0.180 g, 0.44 mmol), triethylamine (4.07 mL, 29.2 mmol) and Pd(OAc)2 (0.098 g, 0.44 mmol) in DMSO (50 mL) and MeOH (50 mL)in a Berghof pressure reactor was evacuated then purged threetimes with carbon monoxide. The mixture was heated to 80 Cfor 18 h under 60 psi of carbon monoxide pressure, cooled and partitioned between EtOAc and water. Column chromatographywith 3:1 hexanes:DCM eluted traces of impurities while elutionwith DCM gave methyl benzofuran-4-carboxylate (2.08 g, 81%).1H NMR (CDCl3) d 7.99 (dd, J = 7.7, 0.9 Hz, 1H), 7.74 (d, J = 2.2 Hz,1H), 7.70 (dt, J = 8.2, 0.9 Hz, 1H), 7.33-7.39 (m, 2H), 3.99 (s, 3H). |