1,1-Dichloroethane → Tert-butyl 9-methyl-3,9-diazaspiro[5.5]undecane-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To an ice cooled solution of 3,9-diaza-spiro[5.5]undecane-3-carboxylic acid tert-butyl ester (1.55 g, 6 mmol) in dichloroethane (50 mL) formaldehyde (0.68 mL, 9 mmol) was added and stirred for 1 h at 0° C. Sodium triacetoxyborohydride (2.54 g, 12 mmol) was added and the reaction stirred at room temperature over night. Aqueous sodium hydrogencarbonate (sat. 50 mL) and water (50 mL) were added and the aqueous phase extracted five times with dichloromethane. The combined organic phase was washed with brine, dried (sodium sulfate), filtered and evaporated. Flash chromatography (dichloromethane/methanol 9:1 with 1% ammonium hydroxide) gave 435 mg (27%) 9-methyl-3,9-diaza-spiro[5.5]undecane-3-carboxylic acid tert-butyl ester.

Provenance & Evidence