Hydrochloric Acid → 1638651-87-2

Participants

Reaction Conditions

Reaction Steps

A 50 ml of flask fitted with magnetic stirrer was charged with 5 ml of THF and was cooled to −78° C., to which 2-methyl-2-butene (0.15 mL, 3 mmol) was added and stirred for 5 minutes. Another 50 ml of flask fitted with magnetic stirrer was charged with tert-butyl 5-formyl-3-oxa-8-azabicyclo[3.2.1]octane-8-carboxylate (71 mg, 0.3 mmol) and tert butanol (5 mL) and was stirred at 25° C., to which the above prepared 2-methyl-2-butene THF solution was added. The resulting mixture was cooled to 0° C., and then a solution of NaH2PO4 (81 mg, 0.52 mmol) in water (5 mL) and a solution of NaClO2 (20 mg, 0.22 mmol) in water (5 mL) were added subsequently. After stirring for 20 minutes at 0° C., the reaction mixture was diluted with water (10 mL), acidified to pH 5-6 using 1N HCl, and extracted with ethyl acetate (50 mL) three times. The combined organic phases were dried over Na2SO4, and concentrated in vacuo to afford 8-tert-butoxycarbonyl-3-oxa-8-azabicyclo[3.2.1]octane-5-carboxylic acid 81k (40 mg, 51%), which was used for next step without further purification. MS: calc'd (MH+) 258, measured (MH+) 258

Provenance & Evidence