methyl 2-(1-benzofuran-3-yl)acetate

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

Procedure: A mixture of 0.4 mol of coumaranone and 0.48 mol of methyl (triphenylphosphoranylidene)acetate in 1 liter of p-xylene is maintained at reflux for 18 h. After cooling to room temperature, the solvent is evaporated off, the residue is taken up in 1 liter of ether, the precipitate is filtered off and washed with ether, the filtrate is concentrated and the expected product is obtained after chromatography on silica (eluent: CH2Cl2). is maintained at reflux for 18 h the solvent is evaporated off the precipitate is filtered off washed with ether the filtrate is concentrated

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

Procedure: A solution of 3-coumaranone (5.0 g, 37 mmol) and methyl(triphenylphosphoranylideneacetate) (13.5 g, 40 mmol) in toluene (70 mL) was heated to reflux for 25 hours. More toluene was added (50 mL), and after a further 5 hours, more methyl(triphenylphosphoranylideneacetate) (0.5 g, 1.5 mmol). After another 19 hours, a further 1.0 g (3.0 mmol) was added, and after a further 21 hours, the solvent was removed in vacuo. Column chromatography (heptane:ethyl acetate 4:1) gave the product as a brown oil, 33 mmol, 89%. to reflux for 25 hours After another 19 hours a further 1.0 g (3.0 mmol) was added after a further 21 hours the solvent was removed in vacuo

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

Procedure: A solution of Example 6 (6.23 g, 33 mmol) and lithium hydroxide monohydrate (1.45 g, 35 mmol) in tetrahydrofuran (50 mL), water (35 mL), and methanol (14 mL) was stirred for 6.5 hours at room temperature. Water (70 mL) was added, and the reaction mixture was acidified to pH 4 using 2 M HCl and extracted with dichloromethane (5×200 mL). The organics were dried (MgSO4) and the solvent removed in vacuo to give a brown solid. This was dissolved in diethyl ether, heptane was added, and the mixture was stirred overnight. Solvent was removed by syringe to give product as a pale brown solid, 27 mmol, 80%. extracted with dichloromethane (5×200 mL) The organics were dried (MgSO4) the solvent removed in vacuo to give a brown solid Solvent was removed by syringe to give product as a pale brown solid, 27 mmol, 80%

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

Procedure: A solution of 3-coumaranone (5.0 g, 37 mmol) and methyl(triphenylphosphoranylideneacetate) (13.5 g, 40 mmol) in toluene (70 mL) was heated to reflux for 25 hours. More toluene was added (50 mL), and after a further 5 hours, more methyl(triphenylphosphoranylideneacetate) (0.5 g, 1.5 mmol). After another 19 hours, a further 1.0 g (3.0 mmol) was added, and after a further 21 hours, the solvent was removed in vacuo. Column chromatography (heptane:ethyl acetate 4:1) gave the product as a brown oil, 33 mmol, 89%. to reflux for 25 hours After another 19 hours a further 1.0 g (3.0 mmol) was added after a further 21 hours the solvent was removed in vacuo

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

Procedure: A solution of 3-coumaranone (5.0 g, 37 mmol) and methyl(triphenylphosphoranylideneacetate) (13.5 g, 40 mmol) in toluene (70 mL) was heated to reflux for 25 hours. More toluene was added (50 mL), and after a further 5 hours, more methyl(triphenylphosphoranylideneacetate) (0.5 g, 1.5 mmol). After another 19 hours, a further 1.0 g (3.0 mmol) was added, and after a further 21 hours, the solvent was removed in vacuo. Column chromatography (heptane:ethyl acetate 4:1) gave the product as a brown oil, 33 mmol, 89%. to reflux for 25 hours After another 19 hours a further 1.0 g (3.0 mmol) was added after a further 21 hours the solvent was removed in vacuo

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

Procedure: LiAlH4 (1.025 g, 37.95 mmol) was suspended in diethyl ether with exclusion of oxygen. A solution of the benzofuran-3-ylacetic acid methyl ester just prepared (2.546 g, 13.4 mmol) in diethyl ether (15 ml) was then slowly added to the mixture and the mixture was stirred at room temperature for 30 min. The course of the reaction was monitored by TLC. For complete hydrolysis of the excess hydride, a mixture of water (2 ml) and diethyl ether (5 ml) was cautiously added dropwise to the mixture. The ethereal solution obtained was filtered over kieselguhr and the filter cake was rinsed with diethyl ether. After removal of the solvent, the desired alcohol was obtained in a yield of 1.93 g (89%) as a pale yellow oil and was employed for the further synthesis without further purification. was then slowly added to the mixture was cautiously added dropwise to the mixture The ethereal solution obtained was filtered over kieselguhr the filter cake was rinsed with diethyl ether After removal of the solvent

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

Procedure: KOtBu (0.673 g, 6 mmol) was dissolved in dry DMF (10 ml) with exclusion of oxygen. Phosphonoacetic acid triethyl ester (0.87 ml, 6 mmol) was then added to the mixture. After 20 min a solution of benzofuran-3(2H)-one (0.536 g, 4 mmol) in dry DMF (10 ml, argon atmosphere) was added to this mixture. The reaction mixture was stirred at room temperature for 1 h and thereafter poured on to ice (50 ml) for working up. The mixture obtained was extracted with diethyl ether (4×20 ml). The organic phase was washed with water (4×20 ml), dried with Na2SO4 and then concentrated. The product formed was purified by column chromatography [silica gel 60 (50 g); cyclohexane, ethyl acetate (4:1)] and obtained in a yield of 0.372 g (48%) as a yellowish oil. The mixture obtained was extracted with diethyl ether (4×20 ml) The organic phase was washed with water (4×20 ml) dried with Na2SO4 concentrated The product formed was purified by column chromatography [silica gel 60 (50 g); cyclohexane, ethyl acetate (4:1)] obtained in a yield of 0.372 g (48%) as a yellowish oil

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

Procedure: KOtBu (0.673 g, 6 mmol) was dissolved in dry DMF (10 ml) with exclusion of oxygen. Phosphonoacetic acid triethyl ester (0.87 ml, 6 mmol) was then added to the mixture. After 20 min a solution of benzofuran-3(2H)-one (0.536 g, 4 mmol) in dry DMF (10 ml, argon atmosphere) was added to this mixture. The reaction mixture was stirred at room temperature for 1 h and thereafter poured on to ice (50 ml) for working up. The mixture obtained was extracted with diethyl ether (4×20 ml). The organic phase was washed with water (4×20 ml), dried with Na2SO4 and then concentrated. The product formed was purified by column chromatography [silica gel 60 (50 g); cyclohexane, ethyl acetate (4:1)] and obtained in a yield of 0.372 g (48%) as a yellowish oil. The mixture obtained was extracted with diethyl ether (4×20 ml) The organic phase was washed with water (4×20 ml) dried with Na2SO4 concentrated The product formed was purified by column chromatography [silica gel 60 (50 g); cyclohexane, ethyl acetate (4:1)] obtained in a yield of 0.372 g (48%) as a yellowish oil

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

Procedure: A solution of benzofuran-3-yl-acetic acid methyl ester (4.0 g, 21 mmol) in 25 ml of ether was added dropwise at RT to a suspension of lithium alanate (1.61 g, 59.5 mmol) in 35 ml of ether, and stirring was then carried out for 30 minutes. Excess alanate was then hydrolysed with ethanol, the mixture was suction-filtered over Kieselguhr, and the solvent was removed in vacuo. The product was obtained in the form of a yellowish oil in a yield of 3.0 g (89%). hydrolysed with ethanol, the mixture was suction-filtered over Kieselguhr the solvent was removed in vacuo The product was obtained in the form of a yellowish oil in a yield of 3.0 g (89%)

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

Procedure: A mixture of 0.4 mol of coumaranone and 0.48 mol of methyl (triphenylphosphoranylidene)acetate in 1 liter of p-xylene is maintained at reflux for 18 h. After cooling to room temperature, the solvent is evaporated off, the residue is taken up in 1 liter of ether, the precipitate is filtered off and washed with ether, the filtrate is concentrated and the expected product is obtained after chromatography on silica (eluent: CH2Cl2). is maintained at reflux for 18 h the solvent is evaporated off the precipitate is filtered off washed with ether the filtrate is concentrated

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

Procedure: A solution of 3-coumaranone (5.0 g, 37 mmol) and methyl(triphenylphosphoranylideneacetate) (13.5 g, 40 mmol) in toluene (70 mL) was heated to reflux for 25 hours. More toluene was added (50 mL), and after a further 5 hours, more methyl(triphenylphosphoranylideneacetate) (0.5 g, 1.5 mmol). After another 19 hours, a further 1.0 g (3.0 mmol) was added, and after a further 21 hours, the solvent was removed in vacuo. Column chromatography (heptane:ethyl acetate 4:1) gave the product as a brown oil, 33 mmol, 89%. to reflux for 25 hours After another 19 hours a further 1.0 g (3.0 mmol) was added after a further 21 hours the solvent was removed in vacuo

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

Procedure: A solution of 3-coumaranone (5.0 g, 37 mmol) and methyl(triphenylphosphoranylideneacetate) (13.5 g, 40 mmol) in toluene (70 mL) was heated to reflux for 25 hours. More toluene was added (50 mL), and after a further 5 hours, more methyl(triphenylphosphoranylideneacetate) (0.5 g, 1.5 mmol). After another 19 hours, a further 1.0 g (3.0 mmol) was added, and after a further 21 hours, the solvent was removed in vacuo. Column chromatography (heptane:ethyl acetate 4:1) gave the product as a brown oil, 33 mmol, 89%. to reflux for 25 hours After another 19 hours a further 1.0 g (3.0 mmol) was added after a further 21 hours the solvent was removed in vacuo