1,2-Dibromoethane → 3-(3,4-Dimethylbenzoyl)-2-methylpropionaldehyde ethylene acetal

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Reaction Steps

0.29 ml (3.4 mmol) of 1,2-dibromoethane was added to a suspension of 1.66 g (68.1 mmol) of magnesium in 5 ml of anhydrous tetrahydrofuran under a stream of nitrogen. 9.96 g (51.1 mmol) of 3-bromo-2-methylpropionaldehyde ethylene acetal [prepared as described in step (i) above] were then added dropwise to the resulting mixture, whilst ice-cooling, after which the mixture was stirred for 1 hour. A solution of 6.58 g (34.1 mmol) of N-methoxy-N-methyl-3,4-dimethylbenzamide in 30 ml of tetrahydrofuran was then added dropwise to the mixture, and the resulting mixture was stirred, whilst ice-cooling for 1 hour. A saturated aqueous solution of ammonium chloride was then added to the mixture, and the resulting mixture was extracted twice with ethyl acetate. The organic extracts were combined and washed with a saturated aqueous solution of sodium chloride, after which they were dried over anhydrous magnesium sulfate and concentrated by evaporation under reduced pressure. The residue thus obtained was applied to a silica gel chromatography column and eluted with a 6:1 by volume mixture of hexane and ethyl acetate, to give 3.26 g (yield 39%) of the title compound as a colorless oily substance.

Provenance & Evidence