反应详情

A solution of 2-trifluoromethyl-furan-3-carboxylic acid ethyl ester (2.2 g, 10.5 mmoles) in tetrahydrofuran (150 ml) was treated portionwise during 0.5 h with lithium aluminium hydride (0.55 g, 14.5 mmoles) under a nitrogen atmosphere. When the addition was complete the mixture was stirred at room temperature for 18 h, then quenched by the addition of excess acetone (1 ml) and then water (1 ml). After diluting with ethyl acetate (200 ml) the grey precipitate was removed by filtration. The filtrate was dried and evaporation of the solvent afforded (2-trifluoromethyl-furan-3-yl)-methanol as a colourless oil. This material was used immediately in the next step. (ii) A solution of the (2-trifluoromethyl-furan-3-yl)-methanol from (i) in dry dichloromethane (180 ml) was treated with chloro-tri-isopropyl-silane (2.6 g, 13.4 mmoles) and imidazole (1.45 g, 21.3 mmoles) and the mixture was stirred overnight at room temperature. Further aliquots of chloro-tri-isopropyl-silane (0.9 g, 4.64 mmoles) and imidazole (0.5 g, 7.34 mmoles) were added and the mixture was stirred for 3 h. The reaction mixture was diluted with water, the organic phase separated and washed sequentially with 0.1M aqueous hydrochloric acid, water, saturated aqueous sodium bicarbonate, water and brine. After drying, evaporation of the solvents afforded a colourless oil. The oil was distilled under reduced pressure (0.05 torr) in a Kugelruhr apparatus collecting the fraction boiling at an oven temperature of 125±20° C. to afford compound 88 as a colourless oil.

1. additionWhen the addition
2. customquenched by the addition of excess acetone (1 ml)
3. additionAfter diluting with ethyl acetate (200 ml) the grey precipitate
4. customwas removed by filtration
5. customThe filtrate was dried
6. customevaporation of the solvent