反应详情

温度

-78 °C

Methyl lithium (670 μl [1.11 mmol, 1.1 equiv] of a 1.65 M solution in diethyl ether) is added dropwise to a stirred solution of (S)-2-(tertbutyidimethylsilyloxy)-γ-butyrolactone 12 (218 mg, 1.01 mmol) in THF (4.0 ml) cooled to −78° C. is added dropwise. After stirring at −78° C. for 3 h, the reaction is quenched by the addition of glacial acetic acid (72 μl, 1.26 mmol, 1.25 equiv). Diethyl ether (20 ml) and saturated aqueous sodium bicarbonate solution (10 ml) are added. After stirring for 5 min the organic layer is separated and the aqueous layer is extracted with diethyl ether (2×20 ml). The combined organic extracts are dried over magnesium sulfate and concentrated in vacua. Crude (3S)-3-(tertbutyidimethylsilyloxy)-2-hydroxy-2-methyl-tetrahydrofurane 13 (235 mg, 93%) is obtained as a colourless crystalline solid (mixture of diastereomers) which is used for the synthesis of (S)-3,5-di-(tert-butyldimethylsilyloxy)-pentan-2-one 14 without further purification.

1. additionis added dropwise
2. stirringAfter stirring for 5 min the organic layer
3. customis separated
4. extractionthe aqueous layer is extracted with diethyl ether (2×20 ml)
5. dry with materialThe combined organic extracts are dried over magnesium sulfate
6. concentrationconcentrated in vacua