methyl N,N-di(propan-2-yl)carbamate

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

Procedure: 478 mg (3 mmol) of methyl N,N-diisopropylcarbamate are lithiated with 392 mg (3.3 mmol) of TMEDA in 4 ml of THF at -78° C. using 3.3 mmol of sec-BuLi. After 1 h, the reaction mixture is treated with 144 mg (2 mmol) of isobutyraldehyde and stirred for 21 h. The reaction mixture is then treated at -78° C. with 10 ml of 2N hydrochloric acid and 10 ml of ether and the mixture is warmed to room temperature. The phases are separated, the aqueous phase is extracted twice with ether and the combined organic phases are neutralized with saturated NaHCO3 solution. After drying over magnesium sulphate, the solvent is stripped off and the crude product of 500 mg weight is purified by chromatography on silica gel using ether/petroleum ether (1:3). 299 mg (64.6% of theory) of the title compound are obtained as a colorless liquid. The phases are separated the aqueous phase is extracted twice with ether After drying over magnesium sulphate the crude product of 500 mg weight is purified by chromatography on silica gel

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

Procedure: 11.148 g (70 mmol) of methyl N,N-diisopropylcarbamate and 12.424 g (105 mmol) of TMEDA in 200 ml of THF are lithiated at -78° C. with 70 mmol of sec. BuLi. After 1 h, 2.453 g (35 mmol) of cyclobutanone are added in portions (about 500 mg every 30 min). The reaction is complete after 3 h (TLC checking) and the reaction mixture is treated in the cold with 100 ml of ether and 120 ml of 2N hydrochloric acid. After warming to room temperature, the phases are separated and the aqueous phase is extracted three times using 50 ml of ether each time. The combined organic phases are then freed from acid with 50 ml of saturated NaHCO3 solution and dried over magnesium sulphate. After the solvent has been stripped off in vacuo, a crude yield of 12.197 g is obtained, chromatographic purification of which on silica gel using ether/petroleum ether (1:1) gives 3.721 g (46.4% of theory) of the title compound as a colorless liquid. are lithiated at -78° C. with 70 mmol of sec The reaction is complete after 3 h the phases are separated the aqueous phase is extracted three times dried over magnesium sulphate a crude yield of 12.197 g is obtained chromatographic purification of which on silica gel