Sodium Methoxide → Bicyclo(3.2.1)octane-2,4-dione

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Reaction Steps

4.27 g (79 mmol) of sodium methanolate in 40 ml of dimethyl sulfoxide are used as initial charge in a reaction vessel. A solution of 7.2 g (52 mmol) of 4-methylene-3-oxa-bicyclo(3.2.1]octan-2-one in 20 ml of dimethyl sulfoxide is fed into that solution in the course of 2.5 hours at a temperature of from 25 to 35° C., with stirring. After a further 0.5 hours, the reaction mixture is diluted with 200 ml of water and extracted twice with 100 ml of ethyl acetate. The combined organic phases are washed with 100 ml of water. The aqueous phases are then combined, adjusted to pH 3 using approximately 35 ml of 2N hydrochloric acid, and extracted four times using 400 ml of ethyl acetate each time. The combined organic phases are washed with water, dried over magnesium sulfate, filtered and concentrated using a rotary evaporator. The brown solid remaining is filtered over silica gel and yields 6.3 g (46 mmol) of bicyclo[3.2.1]octane-2,4-dione with a content of 93%, corresponding to a yield of 81.4%, and a melting point of 129-130° C.

Provenance & Evidence