Potassium Carbonate → Tert-butyl 8-but-2-ynyl-10-(hydroxymethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

Tert-butyl 10-(hydroxymethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (1.35 g, 4.71 mmol), K2CO3 (3.26 g, 23.6 mmol) and 1-bromobut-2-yne (495 μL, 5.66 mmol) were combined in N,N-dimethylformamide (15 mL) and heated for 48 h at 45° C. under nitrogen. The reaction mixture was diluted with ethyl acetate (150 mL) and filtered. The filtrate was washed with water, 50% saturated sodium bicarbonate solution, and brine. The organic layer was dried over Na2SO4, filtered, and concentrated in vacuo. The desired fractions obtained from silica gel chromatography (5-20% methanol/dichloromethane) were combined and concentrated, then brought up in ethyl acetate, filtered and concentrated in vacuo to provide tert-butyl-8-but-2-ynyl-10-(hydroxymethyl)-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (1.12 g, 3.31 mmol, 70%). ESI-MS m/z calc. 338.2. found 339.3 (M+1)+; Retention time: 0.86 minutes (3 min run).

Provenance & Evidence