Formaldehyde → 9-(3,4-Dichloro-phenyl)-3-methyl-3-aza-spiro[5.5]undec-8-ene

Participants

Reaction Conditions

Reaction Steps

To an ice cooled solution of 9-(3,4-dichloro-phenyl)-3-aza-spiro[5.5]undec-8-ene (410 mg, 1.38 mmol) in dichloroethane (12 mL) and methanol (4 mL), formaldehyde (37% in water, 157 μL, 2.08 mmol) was added and stirred for 1 h at 0° C. Sodium triacetoxy-borohydride (585 mg, 2.76 mmol) was added and the mixture stirred at room temperature over night. The reaction was quenched with aqueous sodium hydrogen-carbonate and evaporated. The remaining aqueous phase was extracted four times with dichloromethane and the combined organic phase was dried (sodium sulfate), filtered and evaporated to give 320 mg of crude material. Flash chromatography (dichloromethane/methanol 9:1 with 1% ammonium hydroxide) gave 225 mg (52%) of 9-(3,4-dichloro-phenyl)-3-methyl-3-aza-spiro[5.5]undec-8-ene as an yellow oil.

Provenance & Evidence