ethyl 3-oxooxane-4-carboxylate

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

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

Procedure: A solution of 3-oxo-tetrahydro-pyran-4-carboxylic acid ethyl ester (3.03 g, 17.6 mmol), R-(+)-α-methylbenzylamine (2.35 g, 19.4 mmol) and p-toluenesulfonic acid hydrate (67 mg, 230 μmol) in benzene (60 mL) was heated at reflux under a Dean-Stark trap for 16 h. The cooled mixture was concentrated in vacuo to provide the product as a yellow oily semisolid (5.05 g), used without further purification. at reflux under a Dean-Stark trap for 16 h The cooled mixture was concentrated in vacuo

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

Procedure: A solution of 4-ethoxycarbonylmethoxybutyric acid ethyl ester (90%, 15.0 g, 61.9 mmol) in toluene (300 mL) was stirred at room temperature and treated over 5 min with a solution of potassium tert-butoxide in tetrahydrofuran (1.0 M, 74.2 mL, 74.2 mmol). The mixture was stirred at room temperature for 24 h, then was poured into 1 N hydrochloric acid. The phases were separated, and the aqueous phase was extracted with ether. The combined organic phases were dried (Na2SO4), filtered and concentrated in vacuo. The residue was purified by flash column chromatography (5% ethyl acetate/hexanes) to provide the product as a pale yellow liquid (5.06 g, 48%). The phases were separated the aqueous phase was extracted with ether The combined organic phases were dried (Na2SO4) filtered concentrated in vacuo The residue was purified by flash column chromatography (5% ethyl acetate/hexanes)

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

Procedure: A solution of 4-ethoxycarbonylmethoxybutyric acid ethyl ester (90%, 15.0 g, 61.9 mmol) in toluene (300 mL) was stirred at room temperature and treated over 5 min with a solution of potassium tert-butoxide in tetrahydrofuran (1.0 M, 74.2 mL, 74.2 mmol). The mixture was stirred at room temperature for 24 h, then was poured into 1 N hydrochloric acid. The phases were separated, and the aqueous phase was extracted with ether. The combined organic phases were dried (Na2SO4), filtered and concentrated in vacuo. The residue was purified by flash column chromatography (5% ethyl acetate/hexanes) to provide the product as a pale yellow liquid (5.06 g, 48%). The phases were separated the aqueous phase was extracted with ether The combined organic phases were dried (Na2SO4) filtered concentrated in vacuo The residue was purified by flash column chromatography (5% ethyl acetate/hexanes)

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 ethyl 3-oxotetrahydro-2H-pyran-4-carboxylate (1.0 g, 5.81 mmol) in DCM (30 mL) was added DIPEA (1.22 mL, 6.97 mmol) and Tf2O (1.08 mL, 6.39 mmol) at −78° C., then it was warmed up to room temperature and stirred at room temperature for 2 h, the solution was diluted with DCM, washed with Sat. NaHCO3, brine, dried and concentrated to give ethyl 5-(((trifluoromethyl)sulfonyl)oxy)-3,6-dihydro-2H-pyran-4-carboxylate as crude product (2 g). washed with Sat. NaHCO3, brine dried concentrated

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

Procedure: To a solution of ethyl 3-oxotetrahydro-2H-pyran-4-carboxylate (1.0 g, 5.81 mmol) in DCM (30 mL) was added DIPEA (1.22 mL, 6.97 mmol) and Tf2O (1.08 mL, 6.39 mmol) at −78° C., then it was warmed up to room temperature and stirred at room temperature for 2 h, the solution was diluted with DCM, washed with Sat. NaHCO3, brine, dried and concentrated to give ethyl 5-(((trifluoromethyl)sulfonyl)oxy)-3,6-dihydro-2H-pyran-4-carboxylate as crude product (2 g). washed with Sat. NaHCO3, brine dried concentrated

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

Procedure: A solution of 3-oxo-tetrahydro-pyran-4-carboxylic acid ethyl ester (3.03 g, 17.6 mmol), R-(+)-α-methylbenzylamine (2.35 g, 19.4 mmol) and p-toluenesulfonic acid hydrate (67 mg, 230 μmol) in benzene (60 mL) was heated at reflux under a Dean-Stark trap for 16 h . The cooled mixture was concentrated in vacuo to provide the product as a yellow oily semisolid (5.05 g), used without further purification. 1H NMR (300 mHz, CDCl3) δ8.97 (bd, J=7.3 Hz, 1H), 7.3-7.2 (m, 5H), 4.41 (m, 1H), 4.30 (d, J=16.1 Hz, 1H), 4.18 (q, J=7.3 Hz, 2H), 3.91 (d, J=16.1 Hz, 1H), 3.64 (m, 2H), 2.34 (m, 2H), 1.48 (d, J=6.5 Hz, 3H), 1.30 (t, J=7.3 Hz, 3H). at reflux under a Dean-Stark trap for 16 h The cooled mixture was concentrated in vacuo

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

Procedure: A solution of 4-ethoxycarbonylmethoxybutyric acid ethyl ester (90%, 15.0 g, 61.9 mmol) in toluene (300 mL) was stirred at room temperature and treated over 5 min with a solution of potassium tert-butoxide in tetrahydrofuran (1.0 M, 74.2 mL, 74.2 mmol). The mixture was stirred at room temperature for 24 h , then was poured into 1 N hydrochloric acid. The phases were separated, and the aqueous phase was extracted with ether. The combined organic phases were dried (Na2SO4), filtered and concentrated in vacuo. The residue was purified by flash column chromatography (5% ethyl acetate/hexanes) to provide the product as a pale yellow liquid (5.06 g, 48%). 1H NMR (300 mHz, CDCl3) δ11.85 (s, 1H), 4.24 (q, J=7.3 Hz, 2H), 4.14 (t, J=1.7 Hz, 2H), 3.79 (t, J=5.5 Hz, 2H), 2.35 (tt, J=5.5, 1.7 Hz, 2H), 1.32 (t, J=7.3 Hz, 3H). The phases were separated the aqueous phase was extracted with ether The combined organic phases were dried (Na2SO4) filtered concentrated in vacuo The residue was purified by flash column chromatography (5% ethyl acetate/hexanes)

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

Procedure: A solution of 3-oxo-tetrahydro-pyran-4-carboxylic acid ethyl ester (3.03 g, 17.6 mmol), R-(+)-α-methylbenzylamine (2.35 g, 19.4 mmol) and p-toluenesulfonic acid hydrate (67 mg, 230 μmol) in benzene (60 mL) was heated at reflux under a Dean-Stark trap for 16 h. The cooled mixture was concentrated in vacuo to provide the product as a yellow oily semisolid (5.05 g), used without further purification. at reflux under a Dean-Stark trap for 16 h The cooled mixture was concentrated in vacuo

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

Procedure: A solution of 4-ethoxycarbonylmethoxybutyric acid ethyl ester (90%, 15.0 g, 61.9 mmol) in toluene (300 mL) was stirred at room temperature and treated over 5 min with a solution of potassium tert-butoxide in tetrahydrofuran (1.0 M, 74.2 mL, 74.2 mmol). The mixture was stirred at room temperature for 24 h, then was poured into 1 N hydrochloric acid. The phases were separated, and the aqueous phase was extracted with ether. The combined organic phases were dried (Na2SO4), filtered and concentrated in vacuo. The residue was purified by flash column chromatography (5% ethyl acetate/hexanes) to provide the product as a pale yellow liquid (5.06 g, 48%). The phases were separated the aqueous phase was extracted with ether The combined organic phases were dried (Na2SO4) filtered concentrated in vacuo The residue was purified by flash column chromatography (5% ethyl acetate/hexanes)