Reacción #2638

Ecuación de reacción

tert-butyl methyl ether

4-tert-butyldimethylsiloxy-2-cyclopentenone

lithium bromide

lithium aluminum hydride

→

title compound

Rendimiento 69.2%

cis-4-tert-butyldimethylsilyloxy-2-cyclopentenol

Rendimiento 69.2%

Disolventes

toluene

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroIt is then quenched by slow addition of aqueous sodium hydroxide (1N, 7.0 mL) at a rate
2. 2
   Otrothe temperature of the reaction below 20° C
3. 3
   FiltraciónThe resulting suspension is then filtered through a pad of diatomaceous earth
4. 4
   Lavadothe pad is subsequently rinsed with toluene
5. 5
   OtroThe filtrate phases are separated
6. 6
   Extracciónthe aqueous phase is extracted with toluene
7. 7
   ExtracciónThe organic phase and organic extract
8. 8
   Lavadorinsed with aqueous sodium hydroxide (1N), brine
9. 9
   Secadodried over anhydrous magnesium sulfate
10. 10
    Filtraciónfiltered
11. 11
    Concentraciónconcentrated under vacuum (40° C., 20 mmHg)
12. 12
    workup.DISTILLATIONThe residue is then purified by Kugelrohr distillation (60°-80° C., 1 mmHg)

Procedimiento

A mechanically stirred solution of 4-tert-butyldimethylsiloxy-2-cyclopentenone (501 mg, 2.36 mmol) in anhydrous toluene (10 mL) under an atmosphere of argon is treated with lithium bromide (1.06 g, 12.2 mmol). The mixture is cooled to -20° C. with an ice/salt bath and treated with lithium aluminum hydride (92.0 mg, 2.42 mmol) in one portion followed by tert-butyl methyl ether (1.0 mL). The ice/salt bath is replaced with an ice bath and the reaction is then stirred for 2 hours at 0° C. It is then quenched by slow addition of aqueous sodium hydroxide (1N, 7.0 mL) at a rate that maintains the temperature of the reaction below 20° C. The resulting suspension is then filtered through a pad of diatomaceous earth and the pad is subsequently rinsed with toluene. The filtrate phases are separated and the aqueous phase is extracted with toluene. The organic phase and organic extract are combined, rinsed with aqueous sodium hydroxide (1N), brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum (40° C., 20 mmHg). The residue is then purified by Kugelrohr distillation (60°-80° C., 1 mmHg) to provide the title compound (350 mg, 69% yield) as a colorless oil; cis/trans/1-2+1-4 addition, 92.7/6.3/1.0.

Fuente