Potassium tert-butoxide → Tert-butyl 9-oxo-7-oxa-3,10-diazaspiro[5.6]dodecane-3-carboxylate
Reaction equation
Cl[CH2:2][C:3]([NH:5][CH2:6][CH2:7][C:8]1([OH:21])[CH2:13][CH2:12][N:11]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])[CH2:10][CH2:9]1)=[O:4].CC(C)([O-])C.[K+]>C1COCC1>[O:4]=[C:3]1[NH:5][CH2:6][CH2:7][C:8]2([CH2:13][CH2:12][N:11]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])[CH2:10][CH2:9]2)[O:21][CH2:2]1Participants
4
Procedure
A solution of tert-butyl 4-(2-(2-chloroacetamido)ethyl)-4-hydroxypiperidine-1-carboxylate (example 89, step c) (0.3 g) in dry THF (18 mL) was added dropwise over 6 hours to a refluxing mixture of potassium tert-butoxide (1M in tert-butanol, 3 mL) and dry THF (60 mL). At the end of the addition the mixture was heated at reflux for a further 15 minutes and then cooled to room temperature. The mixture was partitioned between ethyl acetate and brine. The organic layer was dried over sodium sulphate, filtered and the solvent evaporated under reduced pressure. Tritruration with diethylether afforded the subtitled compound. Yield 0.117 g.