反应详情

A solution of 1,2-dibromoethane (5 g) in diethyl ether (10 ml) was added to a stirred suspension of magnesium (3 g) in diethyl ether (10 ml) to initiate the formation of a Grignard reagent. A mixture of 1,2-dibromoethane (16.7 g) and 3-bromothiophene (4 g) in diethyl ether (30 ml) was added dropwise. The mixture was stirred and heated to reflux for 2 hours. A solution of (2S)-2-methyltetrahydropyran-4-one (2 g) in diethyl ether (5 ml) was added and the mixture was heated to reflux for 1 hour. The mixture was partitioned between ethyl acetate and water. The organic phase was dried (MgSO4) and evaporated. The residue was purified by column chromatography using a 7:3 mixture of petroleum ether and ethyl acetate as eluent. There were thus obtained in turn (2S,4R)-4-hydroxy-2-methyl-4-(3-thienyl)tetrahydropyran (0.685 g, 18.5%) and the corresponding (2S,4S)-isomer (1 g, 32%).

1. additionwas added dropwise
2. temperatureheated
3. temperatureto reflux for 2 hours
4. temperaturethe mixture was heated
5. temperatureto reflux for 1 hour
6. customThe mixture was partitioned between ethyl acetate and water
7. dry with materialThe organic phase was dried (MgSO4)
8. customevaporated
9. customThe residue was purified by column chromatography
10. additiona 7:3 mixture of petroleum ether and ethyl acetate as eluent