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

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Reaction Conditions

Reaction Steps

Oil free sodium hydride (2.16 g, 0.09 M) was added to dry dimethyl sulfoxide (250 mL) under nitrogen gas and the mixture was heated to 60-65° C. until a uniform black solution was formed, about 1 h. Then 19.83 g (0.09 M) of trimethylsulfoxonium iodide was added (slight exotherm) and the mixture was stirred until a brown solution occurred, about 30 min. Then a solution of 13.40 g (67.3 mM) of N-t-butyloxycarbonyl-4-piperidone in 50 mL of dimethyl sulfoxide was stirred at room temperature for 1 h. The reaction mixture was then poured into 1 L of cold water and the whole was extracted 4× with 100 mL portions of hexane. The combined hexane extracts was back-washed with 50 mL of water and with brine solution and was dried with magnesium sulfate, filtered and evaporated to give 11.75 g of white crystalline product, 6-t-butyloxycarbonyl-1-oxa-6-azaspiro[2.5]octane, (78% yield).

Provenance & Evidence