ethyl (1R,2R)-2-phenylcyclopropane-1-carboxylate

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

Procedure: To an ice cold solution of 1.62 g of (1R, 2R)-2-phenyl-cyclopropane carboxylic acid (from racemic trans-2-phenyl-cyclopropane carboxylic acid by resolution on a chiral HPLC column) and 2.0 mL of triethylamine and 0.12 g of 4-dimethylaminopyridine was added 1.2 mL of ethyl chloroformate The mixture was allowed to warm and stir for 1 h, then washed with 25 mL of 3N HCl, 25 mL of water, 25 mL of saturated sodium carbonate and dried over magnesium sulfate. Removal of solvents under reduced pressure gave 1.9 g of product as an oil: MS (m+1)=191.1; 1H NMR (400 MHz, CDCl3) 7.3 (dd, 2H), 7.2 (t, 1H), 7.1 (d, 2H), 4.18 (q, 2H), 2.5 (m, 1H), 1.9 (m, 1H), 1.6 (m, 1H), 1.3 (overlapping m and t, 4H). to warm washed with 25 mL of 3N HCl, 25 mL of water, 25 mL of saturated sodium carbonate dried over magnesium sulfate Removal of solvents under reduced pressure

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

Procedure: To an ice cold solution of 1.62 g of (1R, 2R)-2-phenyl-cyclopropane carboxylic acid (from racemic trans-2-phenyl-cyclopropane carboxylic acid by resolution on a chiral HPLC column) and 2.0 mL of triethylamine and 0.12 g of 4-dimethylaminopyridine was added 1.2 mL of ethyl chloroformate The mixture was allowed to warm and stir for 1 h, then washed with 25 mL of 3N HCl, 25 mL of water, 25 mL of saturated sodium carbonate and dried over magnesium sulfate. Removal of solvents under reduced pressure gave 1.9 g of product as an oil: MS (m+1)=191.1; 1H NMR (400 MHz, CDCl3) 7.3 (dd, 2H), 7.2 (t, 1H), 7.1 (d, 2H), 4.18 (q, 2H), 2.5 (m, 1H), 1.9 (m, 1H), 1.6 (m, 1H), 1.3 (overlapping m and t, 4H). to warm washed with 25 mL of 3N HCl, 25 mL of water, 25 mL of saturated sodium carbonate dried over magnesium sulfate Removal of solvents under reduced pressure

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

Procedure: To a mixture of styrene (2.15g, 20.7 mmol) and Rh2 (4S-BNOX)4 (0.0113 g, 0.0131 mmol) in 5.0 mL of anhydrous dichloromethane was added, by syringe at room temperature, ethyl diazoacetate (0298 g, 2.62 mmol) in 3.0 mL of dichloromethane under nitrogen and at an addition rate of 0.8 mL/h (syringe pump). After addition was complete, the dichloromethane solution was passed through a plug of neutral alumina to separate the catalyst, and solvent and excess styrene were removed under reduced pressure Gas chromatographic separation of the trans-isomer produced a material whose specific rotation was -6.4° which corresponded to an enantiomeric excess of the ethyl (1R,2R)-2-phenylcyclopropanecarboxylate. Conversion of the ethyl esters to the 1-menthyl esters by base hydrolysis, acid chloride formation, and esterification with (-)-menthol provided a gas chromatographically separable mixture that showed 25% enantiomeric excess for the (1R,2R)-enantiomer of the trans-2-phenylcyclopropanecarboxylate. was added, by syringe at room temperature After addition to separate the catalyst, and solvent and excess styrene were removed under reduced pressure Gas chromatographic separation of the trans-isomer produced a material whose specific rotation was -6.4° provided a gas chromatographically separable mixture that

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

Procedure: To a mixture of styrene (2.15g, 20.7 mmol) and Rh2 (4S-BNOX)4 (0.0113 g, 0.0131 mmol) in 5.0 mL of anhydrous dichloromethane was added, by syringe at room temperature, ethyl diazoacetate (0298 g, 2.62 mmol) in 3.0 mL of dichloromethane under nitrogen and at an addition rate of 0.8 mL/h (syringe pump). After addition was complete, the dichloromethane solution was passed through a plug of neutral alumina to separate the catalyst, and solvent and excess styrene were removed under reduced pressure Gas chromatographic separation of the trans-isomer produced a material whose specific rotation was -6.4° which corresponded to an enantiomeric excess of the ethyl (1R,2R)-2-phenylcyclopropanecarboxylate. Conversion of the ethyl esters to the 1-menthyl esters by base hydrolysis, acid chloride formation, and esterification with (-)-menthol provided a gas chromatographically separable mixture that showed 25% enantiomeric excess for the (1R,2R)-enantiomer of the trans-2-phenylcyclopropanecarboxylate. was added, by syringe at room temperature After addition to separate the catalyst, and solvent and excess styrene were removed under reduced pressure Gas chromatographic separation of the trans-isomer produced a material whose specific rotation was -6.4° provided a gas chromatographically separable mixture that

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

Procedure: To a stirred mixture of 33 (153 g, 804.25 mmol, 1.00 equiv) in EtOH (1 L) was added 1M aq. LiOH (1 L), and the resultant solution was stirred at reflux for 1 h. Volatile solvent was removed under reduced pressure and the residue diluted with EtOAc (1.5 L). The organic phase was washed with water (3×1 L) and brine (1×1 L), dried (Na2SO4), filtered and concentrated in vacuo to afford 117.5 g (90%) of trans-2-phenylcyclopropane-1-carboxylic acid (35) as a white solid. at reflux for 1 h Volatile solvent was removed under reduced pressure the residue diluted with EtOAc (1.5 L) The organic phase was washed with water (3×1 L) and brine (1×1 L) dried (Na2SO4) filtered concentrated in vacuo

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred mixture of NaH (40.7 g) in DMSO (2.5 L) under N2 was added portion wise trimethyl sulfoxonium iodide (396 g, 1.80 mol, 1.76 equiv). A solution of 31 (180 g, 1.02 mol, 1.00 equiv) in 1:1 DMSO/THF (2 L) was added, and the reaction mixture was stirred at 25° C. overnight. The reaction mixture was quenched with 1N HCl (1 L) and extracted with EtOAc (2×2 L). The combined organic layers were washed with water (2×2 L) and brine (1×2 L), dried (Na2SO4), filtered and concentrated in vacuo. The residue was purified by SiO2 chromatography eluting with EtOAc/petroleum ether (5 to 12.5% EtOAc) to afford 153 g (79%) of trans-ethyl-2-phenylcyclopropane-1-carboxylate (33) as a light yellow oil. The reaction mixture was quenched with 1N HCl (1 L) extracted with EtOAc (2×2 L) The combined organic layers were washed with water (2×2 L) and brine (1×2 L) dried (Na2SO4) filtered concentrated in vacuo The residue was purified by SiO2 chromatography eluting with EtOAc/petroleum ether (5 to 12.5% EtOAc)

Conditions: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred mixture of NaH (40.7 g) in DMSO (2.5 L) under N2 was added portion wise trimethyl sulfoxonium iodide (396 g, 1.80 mol, 1.76 equiv). A solution of 31 (180 g, 1.02 mol, 1.00 equiv) in 1:1 DMSO/THF (2 L) was added, and the reaction mixture was stirred at 25° C. overnight. The reaction mixture was quenched with 1N HCl (1 L) and extracted with EtOAc (2×2 L). The combined organic layers were washed with water (2×2 L) and brine (1×2 L), dried (Na2SO4), filtered and concentrated in vacuo. The residue was purified by SiO2 chromatography eluting with EtOAc/petroleum ether (5 to 12.5% EtOAc) to afford 153 g (79%) of trans-ethyl-2-phenylcyclopropane-1-carboxylate (33) as a light yellow oil. The reaction mixture was quenched with 1N HCl (1 L) extracted with EtOAc (2×2 L) The combined organic layers were washed with water (2×2 L) and brine (1×2 L) dried (Na2SO4) filtered concentrated in vacuo The residue was purified by SiO2 chromatography eluting with EtOAc/petroleum ether (5 to 12.5% EtOAc)

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

Procedure: To an ice cold solution of 1.62 g of (1R, 2R)-2-phenyl-cyclopropane carboxylic acid (from racemic trans-2-phenyl-cyclopropane carboxylic acid by resolution on a chiral HPLC column) and 2.0 mL of triethylamine and 0.12 g of 4-dimethylaminopyridine was added 1.2 mL of ethyl chloroformate The mixture was allowed to warm and stir for 1 h, then washed with 25 mL of 3N HCl, 25 mL of water, 25 mL of saturated sodium carbonate and dried over magnesium sulfate. Removal of solvents under reduced pressure gave 1.9 g of product as an oil: MS (m+1)=191.1; 1H NMR (400 MHz, CDCl3) 7.3 (dd, 2H), 7.2 (t, 1H), 7.1 (d, 2H), 4.18 (q, 2H), 2.5 (m, 1H), 1.9 (m, 1H), 1.6 (m, 1H), 1.3 (overlapping m and t, 4H). to warm washed with 25 mL of 3N HCl, 25 mL of water, 25 mL of saturated sodium carbonate dried over magnesium sulfate Removal of solvents under reduced pressure

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

Procedure: To an ice cold solution of 1.62 g of (1R, 2R)-2-phenyl-cyclopropane carboxylic acid (from racemic trans-2-phenyl-cyclopropane carboxylic acid by resolution on a chiral HPLC column) and 2.0 mL of triethylamine and 0.12 g of 4-dimethylaminopyridine was added 1.2 mL of ethyl chloroformate The mixture was allowed to warm and stir for 1 h, then washed with 25 mL of 3N HCl, 25 mL of water, 25 mL of saturated sodium carbonate and dried over magnesium sulfate. Removal of solvents under reduced pressure gave 1.9 g of product as an oil: MS (m+1)=191.1; 1H NMR (400 MHz, CDCl3) 7.3 (dd, 2H), 7.2 (t, 1H), 7.1 (d, 2H), 4.18 (q, 2H), 2.5 (m, 1H), 1.9 (m, 1H), 1.6 (m, 1H), 1.3 (overlapping m and t, 4H). to warm washed with 25 mL of 3N HCl, 25 mL of water, 25 mL of saturated sodium carbonate dried over magnesium sulfate Removal of solvents under reduced pressure

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

Procedure: To a mixture of styrene (2.15 g, 20.7 mmol) and Rh2 (4S-BNOX)4 (0.0113 g, 0.0131 mmol) in 5.0 mL of anhydrous dichloromethane was added, by syringe at room temperature, ethyl diazoacetate (0298 g, 2.62 mmol) in 3.0 mL of dichloromethane under nitrogen and at an addition rate of 0.8 mL/h (syringe pump). After addition was complete, the dichloromethane solution was passed through a plug of neutral alumina to separate the catalyst, and solvent and excess styrene were removed under reduced pressure. Gas chromatographic separation of the trans-isomer produced a material whose specific rotation was -6.4° which corresponded to an enantiomeric excess of the ethyl (1R,2R)-2-phenylcyclopropanecarboxylate. Conversion of the ethyl esters to the 1-menthyl esters by base hydrolysis, acid chloride formation, and esterification with (-)-menthol provided a gas chromatographically separable mixture that showed 25% enantiomeric excess for the (1R,2R)-enantiomer of the trans-2-phenylcyclopropanecarboxylate. was added, by syringe at room temperature After addition to separate the catalyst, and solvent and excess styrene were removed under reduced pressure Gas chromatographic separation of the trans-isomer produced a material whose specific rotation was -6.4° provided a gas chromatographically separable mixture that

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

Procedure: To a mixture of styrene (2.15g, 20.7 mmol) and Rh2(4S-BNOX)4 (0.0113 g, 0.0131 mmol) in 5.0 mL of anhydrous dichloromethane was added, by syringe at room temperature, ethyl diazoacetate (0298 g, 2.62 mmol) in 3.0 mL of dichloromethane under nitrogen and at an addition rate of 0.8 mL/h (syringe pump). After addition was complete, the dichloromethane solution was passed through a plug of neutral alumina to separate the catalyst, and solvent and excess styrene were removed under reduced pressure Gas chromatographic separation of the trans-isomer produced a material whose specific rotation was −6.4° which corresponded to an enantiomeric excess of the ethyl (1R,2R)-2-phenylcyclopropanecarboxylate. Conversion of the ethyl esters to the 1-menthyl esters by base hydrolysis, acid chloride formation, and esterification with (−)-menthol provided a gas chromatographically separable mixture that showed 25% enantiomeric excess for the (1R,2R)-enantiomer of the trans-2-phenylcyclopropanecarboxylate. was added, by syringe at room temperature After addition to separate the catalyst, and solvent and excess styrene were removed under reduced pressure Gas chromatographic separation of the trans-isomer produced a material whose specific rotation was −6.4° provided a gas chromatographically separable mixture that

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

Procedure: To a suspension of styrene (3.00 g) and rhodium(II) acetate dimer (40.0 mg) in 1,2-dichloroethane (29.0 mL), a solution of ethyl diazoacetate (3.03 mL) in 1,2-dichloroethane (29.0 mL) was added over a period of 4 hours and the mixture was stirred at room temperature for 19 hours. The reaction mixture was concentrated under reduced pressure and purified by silica gel column chromatography (n-hexane:diethyl ether=20:1) to give ethyl trans-2-phenylcyclopropanecarboxylate as a colorless oil (2.42 g) and ethyl cis-2-phenylcyclopropanecarboxylate as a colorless oil (1.51 g). The reaction mixture was concentrated under reduced pressure purified by silica gel column chromatography (n-hexane:diethyl ether=20:1)