Réaction #87231

Équation de réaction

sodium bicarbonate

(3R,4R,5S)-4-hydroxy-5-methyl-3-phenethyldihydrofuran-2(3H)-one

2,6-dimethylpyridine

triisopropylsilyl trifluoromethanesulfonate

→

(3R,4R,5S)-5-methyl-3-phenethyl-4-((triisopropylsilyl)oxy)dihydro-furan-2(3H)-one

Rendement 59.2%

Solvants

CH2Cl2

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONmixed thoroughly
2. 2
   AutreThe phases were separated
3. 3
   Extractionthe aqueous extracted with CH2Cl2 (2×25 mL)
4. 4
   SéchageThe combined CH2Cl2 extracts were dried
5. 5
   Concentrationconcentrated to a colorless oil which
6. 6
   Autrewas purified by flash chromatography (SiO2, 0→50% EtOAc/hexanes)

Mode opératoire

To a solution of (3R,4R,5S)-4-hydroxy-5-methyl-3-phenethyldihydrofuran-2(3H)-one (800 mg, 3.63 mmol) in CH2Cl2 (20 mL) were added 2,6-dimethylpyridine (592 μl, 5.08 mmol) and triisopropylsilyl trifluoromethanesulfonate (1171 μL, 4.36 mmol) at 0° C., and the mixture was warmed to room temperature while stirring overnight. The reaction mixture was poured onto 50 mL saturated sodium bicarbonate solution and mixed thoroughly. The phases were separated, and the aqueous extracted with CH2Cl2 (2×25 mL). The combined CH2Cl2 extracts were dried and concentrated to a colorless oil which was purified by flash chromatography (SiO2, 0→50% EtOAc/hexanes) to give (3R,4R,5S)-5-methyl-3-phenethyl-4-((triisopropylsilyl)oxy)dihydro-furan-2(3H)-one (809 mg, 53%): 1H NMR (400 MHz, CDCl3) δ 7.33-7.25 (m, 2H), 7.25-7.17 (m, 3H), 3.98 (dd, J=5.9, 4.8 Hz, 1H), 4.34-4.24 (m, 1H), 2.99-2.88 (m, 1H), 2.88-2.76 (m, 1H), 2.61-2.51 (m, 1H), 2.04-1.94 (m, 2H), 1.43 (d, J=6.5 Hz, 3H), 1.09-0.99 (m, 21H); 13C NMR (101 MHz, CDCl3) δ 176.64, 140.98, 128.57, 128.51, 126.16, 82.10, 79.45, 49.17, 32.96, 31.14, 19.10, 18.00, 17.71; ESIMS m/z 378 ([M+H]+).

Source