反应详情

温度

-78 °C

A mixture of n-butyllithium (1.6 M in hexanes, 8.8 ml) and anhydrous ether (20 ml) was stirred at −78° C. under argon and a solution of 2-bromopyridine (1.22 ml) in anhydrous ether (20 ml) added dropwise over 10 minutes. The resulting deep red solution was stirred for 10 minutes and a solution of cyclohexanedione monoethylene ketal (2 g) in tetrahydrofuran (20 ml) then introduced dropwise over 10 minutes. The resulting green suspension was maintained at −78° C. for one hour then warmed to −20° C. and stirred for a further hour, after which a yellow solution had formed. The reaction was quenched with saturated aqueous ammonium chloride (60 ml) and the layers separated. The aqueous was partitioned with dichloromethane (2×80 ml) and combined organics were dried (sodium sulphate) and concentrated in vacuo to give a yellow oil. This was adsorbed onto silica for purification by chromatography eluting with 0-100% ethyl acetate/isohexane to give 8-pyridin-2-yl-1,4-dioxaspiro[4.5]decan-8-ol as a pale yellow solid (1.45 g, 48%).

1. stirringThe resulting deep red solution was stirred for 10 minutes
2. temperatureThe resulting green suspension was maintained at −78° C. for one hour
3. temperaturethen warmed to −20° C.
4. stirringstirred for a further hour
5. customafter which a yellow solution had formed
6. customThe reaction was quenched with saturated aqueous ammonium chloride (60 ml)
7. customthe layers separated
8. customThe aqueous was partitioned with dichloromethane (2×80 ml)
9. dry with materialcombined organics were dried (sodium sulphate)
10. concentrationconcentrated in vacuo
11. customto give a yellow oil
12. customThis was adsorbed onto silica for purification by chromatography
13. washeluting with 0-100% ethyl acetate/isohexane