Dimethyl Sulfoxide → tert-Butyl 2-(1-oxoprop-1-yl)-1-oxo-8-azaspiro[4.5]decane-8-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of oxalyl chloride (1.6 mL, 18.3 mmol) in dichloromethane (150 mL) at −78° C. was slowly added dimethyl sulfoxide (2.6 mL, 37 mmol). After 5 min, a solution of tert-butyl 2-(1-hydroxyprop-1-yl)-1-oxo-8-azaspiro[4.5]decane-8-carboxylate (4.75 g, 15.3 mmol) from Step H in dichloromethane (40 mL) was added via an addition funnel. The reaction mixture was stirred for 45 min at −78° C. and then triethylamine (10.2 mL, 73.2 mmol) was added. After 5 min, the reaction mixture was removed from the cooling bath, allowed to warm to room temperature for 1.5 h, poured into water, and extracted three times with dichloromethane. The organic layers were combined, washed with brine, dried over sodium sulfate, filtered and concentrated to afford 4.65 g. The residue was purified by flash chromatography eluting with 15% ethyl acetate in hexanes to give the title compound (3.98 g) as a pink oil.

Provenance & Evidence