tert-butyl 2,2-dimethylpyrrolidine-1-carboxylate

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Add sec-butyllithium (2.9 mL, 2.1 mmol) dropwise to a solution of freshly distilled (−)-sparteine (1 mL, 4.3 mmol) in diethyl ether (25 mL) over 3 min at −78° C. Add 2,2-dimethylpyrrolidine-1-carboxylic acid tert-butyl ester (645 mg, 3.2 mmol) in diethyl ether (2 mL) dropwise over 10 min. Stir 2 h, add 2-(S)-dibenzylamino-3-phenylpropionaldehyde (967 mg, 2.9 mmol) in diethyl ether (2 mL) over 5 min and stir 20 min. Add saturated aqueous ammonium chloride solution and ethyl acetate and let warm to room temperature, separate the layers, extract the aqueous layer with ethyl acetate, wash the organic layer with saturated aqueous sodium chloride solution, dry (magnesium sulfate), concentrate and purify (silica gel chromatography, eluting with 4:1 hexanes:ethyl acetate) to give the title compound as a colorless oil (182 mg, 12%). stir 20 min separate the layers extract the aqueous layer with ethyl acetate wash the organic layer with saturated aqueous sodium chloride solution dry (magnesium sulfate) concentrate purify (silica gel chromatography, eluting with 4:1 hexanes:ethyl acetate)

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Add sec-butyllithium (2.9 mL, 2.1 mmol) dropwise to a solution of freshly distilled (−)-sparteine (1 mL, 4.3 mmol) in diethyl ether (25 mL) over 3 min at −78° C. Add 2,2-dimethylpyrrolidine-1-carboxylic acid tert-butyl ester (645 mg, 3.2 mmol) in diethyl ether (2 mL) dropwise over 10 min. Stir 2 h, add 2-(S)-dibenzylamino-3-phenylpropionaldehyde (967 mg, 2.9 mmol) in diethyl ether (2 mL) over 5 min and stir 20 min. Add saturated aqueous ammonium chloride solution and ethyl acetate and let warm to room temperature, separate the layers, extract the aqueous layer with ethyl acetate, wash the organic layer with saturated aqueous sodium chloride solution, dry (magnesium sulfate), concentrate and purify (silica gel chromatography, eluting with 4:1 hexanes:ethyl acetate) to give the title compound as a colorless oil (182 mg, 12%). stir 20 min separate the layers extract the aqueous layer with ethyl acetate wash the organic layer with saturated aqueous sodium chloride solution dry (magnesium sulfate) concentrate purify (silica gel chromatography, eluting with 4:1 hexanes:ethyl acetate)

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Add sec-butyllithium (2.9 mL, 2.1 mmol) dropwise to a solution of freshly distilled (−)-sparteine (1 mL, 4.3 mmol) in diethyl ether (25 mL) over 3 min at −78° C. Add 2,2-dimethylpyrrolidine-1-carboxylic acid tert-butyl ester (645 mg, 3.2 mmol) in diethyl ether (2 mL) dropwise over 10 min. Stir 2 h, add 2-(S)-dibenzylamino-3-phenylpropionaldehyde (967 mg, 2.9 mmol) in diethyl ether (2 mL) over 5 min and stir 20 min. Add saturated aqueous ammonium chloride solution and ethyl acetate and let warm to room temperature, separate the layers, extract the aqueous layer with ethyl acetate, wash the organic layer with saturated aqueous sodium chloride solution, dry (magnesium sulfate), concentrate and purify (silica gel chromatography, eluting with 4:1 hexanes:ethyl acetate) to give the title compound as a colorless oil (182 mg, 12%). stir 20 min separate the layers extract the aqueous layer with ethyl acetate wash the organic layer with saturated aqueous sodium chloride solution dry (magnesium sulfate) concentrate purify (silica gel chromatography, eluting with 4:1 hexanes:ethyl acetate)