Reacción #607397

Ecuación de reacción

solution

(2Z,4E)-methyl 5-((S)-1-hydroxy-2,6,6-trimethyl-4-oxocyclohex-2-en-1-yl)-3-methylpenta-2,4-dienoate

methyl iodide

Lithium hexamethyl disilazane

→

title compound

(2Z,4E)-methyl 5-((S)-1-hydroxy-2,3,6,6-tetramethyl-4-oxocyclohex-2-en-1-yl)-3-methylpenta-2,4-dienoate

Disolventes

tetrahydrofuran

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrothe ice bath was removed
2. 2
   workup.STIRRINGThe resulting solution was stirred at ambient temperature overnight
3. 3
   OtroThe reaction was quenched with saturated aqueous ammonium chloride solution (200 ml) and water (200 ml)
4. 4
   Extracciónextracted with ethyl acetate (3×150 ml)
5. 5
   SecadoThe combined organic solution was dried (MgSO4)
6. 6
   Filtraciónfiltered
7. 7
   Concentraciónconcentrated
8. 8
   OtroThe residue was purified on a silica gel column
9. 9
   Lavadoeluted with ethyl acetate and hexane

Procedimiento

A solution of Example 1a (27.8 g, 0.1 mole) in anhydrous tetrahydrofuran (THF, 600 ml) was cooled to 0° C. with an ice bath under an atmosphere of nitrogen. Lithium hexamethyl disilazane (1.0 M solution in THF, 150 ml) was added dropwise via a syringe over about 30 minutes. The resulting solution was stirred at 0° C. for 30 minutes and the ice bath was removed. A solution of methyl iodide (8.09 ml, 18.4 g, 0.13 mole) in anhydrous THF (20 ml) was added via a syringe over 20 minutes. The resulting solution was stirred at ambient temperature overnight. The reaction was quenched with saturated aqueous ammonium chloride solution (200 ml) and water (200 ml) and extracted with ethyl acetate (3×150 ml). The combined organic solution was dried (MgSO4), filtered and concentrated. The residue was purified on a silica gel column eluted with ethyl acetate and hexane. The title compound was obtained as a white solid (17.1 g). 1HNMR (CDCl3): δ7.84 (d, 1H), 6.16 (d, 1H), 5.75 (s, 1H), 3.70 (s, 3H), 2.44 (d, 1H), 2.34 (d, 1H), 2.00 (s, 3H), 1.88 (s, 3H), 1.83 (s, 3H), 1.07 (s, 3H), 1.00 (s, 3H). MS (ESI—): m/e=291.

Fuente