Reaktion #1702034

Reaktionsgleichung

HCl

diisopropylethylamine

acetyl bromide

5

3-Methoxydodecanal

AlMe3

→

6

Ausbeute 77.3%

(4R)-4-((2RS)-2-Methoxyundecyl)oxetan-2-one

Ausbeute 77.3%

Lösungsmittel

CH2Cl2

CH2Cl2

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooled to −45° C.
2. 2
   workup.STIRRINGThe resulting pale yellow solution was stirred for 14 h at −45° C.
3. 3
   Temperaturwarmed to rt
4. 4
   workup.ADDITIONpoured into a separatory funnel
5. 5
   WaschenThe organic layer was washed with saturated NaHCO3, brine
6. 6
   Trocknendried (Na2SO4)
7. 7
   SonstigeThe solvent was removed in vacuo
8. 8
   Sonstigethe yellow oily product was purified by chromatography on SiO2 (4% EtOAc/hexanes to 6% EtOAc/hexanes)

Vorschrift

A solution of N,N′-(1R,1′R)-1,1′-(benzylazanediyl)bis(2-methylpropane-1,1-diyl)bis(1,1,1-trifluoromethanesulfonamide) (81.2 mg, 0.15 mmol, 30 mol %) in CH2Cl2 (1 mL) was treated at rt under N2 slowly with a solution of AlMe3 (10.8 mg, 0.15 mmol) in CH2Cl2 (0.5 mL). The mixture was stirred at room temperature (rt) for 2 h, cooled to −45° C. and treated sequentially with diisopropylethylamine (11 mg, 1.7 equiv), acetyl bromide (117 mg, 1.9 equiv) and 5 (107 mg, 0.500 mmol, 1.0 equiv). The resulting pale yellow solution was stirred for 14 h at −45° C., warmed to rt, and poured into a separatory funnel containing 0.1 N HCl (10) mL). The organic layer was washed with saturated NaHCO3, brine, and dried (Na2SO4). The solvent was removed in vacuo and the yellow oily product was purified by chromatography on SiO2 (4% EtOAc/hexanes to 6% EtOAc/hexanes) to give 6 (99.1 mg, 77%) as a colorless oil: 1H NMR (CDCl3) 4.8-4.65 (m, 1H), 3.60-3.50 (m, 1H), 3.3-3.2 (m, 1H), 3.35, 3.32 (2s, 3H), 3.22-3.08 (m, 1H), 2.18-1.82 (m, 2H) 1.65-1.35 (m, 2H), 1.35-1.20 (m, 14H), 0.90-0.80 (m, 3H).

Quelle