Reaktion #5658

Reaktionsgleichung

benzyl bromide

Benzhydryl 4-(2-furyl)-3-oxaoctanoate

Sodium bis(trimethylsilyl)-amide

→

(2S,4S) Benzhydryl 2-Benzyl-4-(2-furyl)-3-oxaoctanoate

Lösungsmittel

HMPA

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooled to -80°±5° C. under dry argon
2. 2
   Sonstigeat -80°±5° C
3. 3
   workup.DISTILLATIONAfter 15 m, freshly distilled
4. 4
   workup.ADDITIONwas added dropwise
5. 5
   Temperaturmaintaining the reaction temperature at -75°±5 ° C
6. 6
   Sonstigebefore quenching with water and extraction with ether
7. 7
   WaschenThe combined ether extracts were washed with saturated NH4Cl, 5% NaHCO3, brine,dried over MgSO4
8. 8
   Sonstigepurified by flash silica gel chromatography
9. 9
   Sonstigeto give 771.3 mg (31%)
10. 10
    Sonstige[α]25D - 65.5°

Vorschrift

Benzhydryl 4-(2-furyl)-3-oxaoctanoate (2.0 g, 5.28 mmol) was dissolved in 20 mL freshly distilled THF and cooled to -80°±5° C. under dry argon. Sodium bis(trimethylsilyl)-amide (1.0M in THF, 5.6 mL, 5.6 mmol) was slowly added keeping the temperature at -80°±5° C. After 15 m, freshly distilled and filtered (through basic alumina) benzyl bromide (0.7 mL, 5.81 mmol) in HMPA (4 mL) was added dropwise maintaining the reaction temperature at -75°±5 ° C. After 15 m, the reaction was allowed to warm to 0° C. for 1 h before quenching with water and extraction with ether. The combined ether extracts were washed with saturated NH4Cl, 5% NaHCO3, brine,dried over MgSO4, and purified by flash silica gel chromatography to give 771.3 mg (31%): [α]25D - 65.5°; 1H NMR (300 MHz, CDCl3) δ 0.81 (t, 3H, J=7 Hz), 1.22 (m, 4H), 1.80 (m, 2H), 2.91 (m, 2H), 4.12 (dd, 1H, J=9 Hz), 4.30 (t, 1H, J=7 Hz), 5.86 (m, 1H), 6.19 (m, 1H), 6.69

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