3-Butyl-5-methyl-isoxazole-4-carbaldehyde → 3-[(E)-2-(3-Butyl-5-methyl-isoxazol-4-yl)-vinyl]-isoxazole-5-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

To a solution of 3-(diphenyl-phosphinoylmethyl)-isoxazole-5-carboxylic acid ethyl ester (410 mg, 1.2 mmol) in THF (10 mL) at −78° C. was added BuLi (1.6 M in hexanes, 0.79 mL, 1.3 mmol) and the mixture warmed up to 0° C. over 1 h and a solution of 3-butyl-5-methyl-isoxazole-4-carbaldehyde (193 mg, 1.2 mmol) in THF (5 mL) added and stirred for 2 h. The mixture was extracted with ethyl acetate and the combined organic layers were then washed with water and brine and then dried over sodium sulfate, filtered and evaporated. Purification by chromatography (silica, heptane:ethyl acetate=100:0 to 7:3) afforded the title compound (75 mg, 21%) as a colourless oil. MS: m/e=305.2 [M+H]+.

Provenance & Evidence