Water → tert-Butyl 1-oxa-6-azaspiro(2.5)octane-6-carboxylate

Participants

Reaction Steps

Potassium t-butoxide (31 g) was added to a stirred suspension of trimethylsulfoxonium iodide (60.8 g) in 1,2-dimethoxyethane (250 ml) at 20° C. After 1 hour, the mixture was added portionwise over 30 minutes to a stirred solution of 4-oxo-1-piperidinecarboxylic acid, 1,1-dimethylethyl ester (50 g) in 1,2-dimethoxyethane (50 ml) at 0° C. After a further 2 hours, water (500 ml) was added and the mixture extracted with tert.-butyl methyl ether (2×500 ml). The organic extracts were washed separately with saturated sodium bicarbonate solution (250 ml), combined, dried over anhydrous magnesium sulphate, filtered and evaporated under reduced pressure. The residual oil was co-evaoprated with toluene (100 ml) to give the sub-title compound (43.25 g, 81%) as a solid.

Provenance & Evidence