3-Methyl-2-butanone → 1-(3,4-dihydro-2H-1,5-benzodioxepine-7-yl)-4-methyl-1-penten-3-one

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Reaction Steps

The MeOH (5 mL) solution of 3,4-dihydro-2H-1,5-benzodioxepine-7-carbaldehyde (445 mg) and 3-methyl-2-butanone (195 mg) was treated with aq. sodium hydroxide (1N, 1 ml) and the mixture was stirred for 24 hours. The reaction was partitioned between 10 ml water and 40 ml ethyl acetate. The organic layer was then sequentially washed with aq. hydrochloric acid (1N, 20 ml), water (20 ml), and Brine (20 ml) and then concentrated under reduced pressure. The residue was purified with flash chromatography on silica (33% ethyl acetate in hexane) to give the desired product as a white crystal.

Provenance & Evidence