2,2,5,5-Tetramethyltetrahydro-3-ketofuran → 4-(5-Bromo-2-ethylbenzylidene)-2,2,5,5-tetramethyldihydrofuran-3-one

Beteiligte Stoffe

Reaktionsschritte

To an ice-cold solution of dihydro-2,2,5,5-tetramethyl-3(2H)-furanone (13.4 g, 94.34 mmol) in anhydrous 1,2-dimethoxyethane (32 ml) is added sodium methoxide (5.6 g, 103.8 mmol) in one portion, and the reaction mixture is stirred at this temperature for 5 minutes. To the resulting slurry is then added a solution of 5-bromo-2-ethyl-benzaldehyde (20 g, 94.34 mmol) in 1,2-dimethoxyethane (32 ml) dropwise over 10 minutes. The solution is next stirred at 0° C. for 1 hour, then diluted with diethyl ether and washed with 2M hydrochloric acid (×2). Organic fractions are combined, dried over magnesium sulphate, filtered and the filtrate evaporated in vacuo to afford 4-(5-bromo-2-ethylbenzylidene)-2,2,5,5-tetramethyldihydrofuran-3-one (30.2 g) as a yellow liquid.

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