Diisopropylethylamine → Di-tert-butyl dicarbonate

Participants

Reaction Steps

A mixture of 3-(tert-butyl-dimethyl-silanyloxymethyl)-4-chloro-benzylamine (2.00 g, 7.00 mmol) and cyclopropancarboxaldehyde (0.784 mL, 10.5 mmol) in MeOH (70 mL) was heated to reflux for 4 h. The mixture allowed to cool to rt. NaBH4 (397 mg, 10.5 mmol) was added in portion, and the mixture was stirred for 1 h at rt. The solvents were removed under reduced pressure, and the resulting oil was diluted with EtOAc. The resulting mixture was washed with aq. sat. NaHCO3 and brine. The org. layer was dried over MgSO4, filtered, and the solvents were removed under reduced pressure to yield the crude [3-(tert-butyl-dimethyl-silanyloxymethyl)-4-chloro-benzyl]-cyclopropylmethyl-amine. This crude product was dissolved in CH2Cl2 (70 mL). DIPEA (3.60 mL, 21.0 mmol) and Boc2O (2.30 g, 10.5 mmol) were added. The mixture was stirred at rt for 2 h, and the mixture was diluted with CH2Cl2 (30 mL). The resulting mixture was washed with aq. 1M HCl, aq. sat. NaHCO3, and brine. The org. layer was dried over MgSO4, filtered, and the solvents were removed under reduced pressure. Purification of the crude by FC (heptane→EtOAc/heptane 10:90) yielded the title compound contaminated with Boc2O (3.60 g, quantitative yield). LC-MS: tR=1.25 min; ES+: 440.80.

Provenance & Evidence