Triethylamine → 3,3,3-Trifluoro-2-hydroxy-2-[(1-methyl-1,2,3,4-tetrahydro-1-naphthalenyl)methyl]propanal

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Reaction Conditions

Reaction Steps

To a solution of 3,3,3-trifluoro-2-[(1-methyl-1,2,3,4-tetrahydro-1-naphthalenyl)methyl]-1,2-propanediol (Intermediate 5) (1.6 g, 5.55 mmol) in anhydrous dichloromethane (36 ml), anhydrous dimethylsulphoxide (12 ml) and triethylamine (4.9 ml, 35 mmol) stirred under nitrogen in a bath at 8.5° C., was added pyridine-sulphur trioxide complex (4.45 g, 28 mmol) portionwise over 20 min. The solution was stirred in the ice-water bath for a further 1.5 h and then allowed to warm to 21° C. and stirred for 17 h. The reaction mixture was added to aqueous ammonium chloride solution (100 ml) and dichloromethane (100 ml) and the layers were separated. The aqueous layer was re-extracted with dichloromethane (100 ml) and the combined organic layers were washed successively with water (6×100 ml) and saturated brine (100 ml), dried over anhydrous magnesium sulphate and evaporated. The yellow oil obtained was purified by flash chromatography on a 90 g Biotage cartridge eluting with 5% ether in cyclohexane to give the title compound as an oil (1.24 g, 78%).

Provenance & Evidence