Reaktion #158246

Reaktionsgleichung

bromide

tosylate

mesylate

DMF

DBU

HCl

DBU

NaI

→

(1RS,2SR,4SR)-2-methyl-3-methylenebicyclo[2.2.1]heptane-2-carbaldehyde

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeTo a 3 necked 100 ml round bottomed flask equipped with a magnetic stirrer
2. 2
   TemperaturThe reaction was cooled to 20°
3. 3
   Extraktionextracted with Et2O
4. 4
   Waschenafter washing with brine
5. 5
   Trocknenthe organic layer was dried over Na2SO4
6. 6
   Filtrationfiltered
7. 7
   Sonstigeevaporated
8. 8
   Sonstigeto obtain an oil
9. 9
   SonstigeA purification over a 12 g SiO2 cartridge with cyclohexane/AcOEt 95:5
10. 10
    Sonstigeafforded 3

Vorschrift

A 1M soln. of NaBH4 (0.36 ml, 0.36 mmol) in EtOH was added to a suspension of Ni(OAc)2 (89 mg, 0.36 mmol) in EtOH (1.3 ml) under H2. After 30 min, a soln. of 2 (424 mg, 2.86 mmol) in EtOH/H2O 9:1 (1 ml) was added. The mixture was stirred at 20° under 1 atm of H2, until absorption of 1.0 mol.-equiv. of H2. Filtration, then concentration of the reaction mixture afforded pure 3 in 95% yield. Also obtained in 53% yield from 13b (X=Br) or 13e (X=OTs), or 73% yield from 13f (X=OMs) according to the following DBU elimination procedure: To a 3 necked 100 ml round bottomed flask equipped with a magnetic stirrer, a thermometer and a water refrigerant under Ar, were added 13 (bromide, or tosylate or mesylate 1.613 mmol), DMF (10 ml). NaI (242 mg, 1.613 mmol) and DBU (614 mg, 4.03 mmol). The mixture was stirred at 80° for 50 hrs. The reaction was cooled to 20° and poured onto 2% aq. HCl, then extracted with Et2O, after washing with brine, the organic layer was dried over Na2SO4, filtered and evaporated to obtain an oil. A purification over a 12 g SiO2 cartridge with cyclohexane/AcOEt 95:5 afforded 3.

Quelle