Dihydrojasmone → 4-Hydroxy-3-methyl-2-pentyl-cyclopent-2-enone

Experimental description: 270 μL dihydrojasmone were dissolved in 1.2 mL ethanol and added to 150 mL potassium phosphate buffer pH 8.0. Var2 was added to the mixture at a final concentration of 2 μM. The mixture was split in 4.8 mL aliquots into 15 mL scintillation vials equipped with a stir bar. 600 μL 10 mM NADPH in KPi buffer were added to each vial and stirred for 2 minutes. 600 μL cofactor regeneration solution containing 500 mM glucose-6-phosphate and 10 units/mL glucose-6-phosphate dehydrogenase were then added to each vial. The resulting mixtures were stirred at room temperature. After 36 hours, the reaction mixtures were joined together and extracted with chloroform (3×50 mL). The organic phase was then dried over magnesium sulfate (MgSO4) and evaporated in vacuo. Purification of the resulting oil by silica gel chromatography (0-30% ethyl acetate/hexane) afforded the activated product (4-hydroxy-3-methyl-2-pentylcyclopent-2-enone, 222 mg). 210 mg (1.15 mmol) of activated product were dissolved in 2 mL dry dichloromethane (CH2Cl2) and a catalytic amount (4 drops) of ethanol was added to the solution. The solution was cooled to −78° C. (dry ice) and added with 215 μL DAST (1.5 mmol). The reaction was stirred in dry ice for 12 hours. The reaction mixture was then added with 5 mL saturated sodium bicarbonate (NaHCO3) and extracted with dichloromethane (3×15 mL). The organic phase was then dried over magnesium sulfate (MgSO4) and evaporated in vacuo. Purification of the resulting oil by silica gel chromatography (0-30% ethyl acetate/hexane) afforded the fluorinated product, 4-fluoro-3-methyl-2-pentylcyclopent-2-enone (193 mg, 92% yield, yellow oil). 1H-NMR (300 MHz, CDCl3): δ 0.88 (t, J=6.6 Hz, 3H, CH3), δ 1.25-1.40 (m, 6H, CH2), δ 2.10 (d, J=2.1 Hz, 2H, CH3), δ 2.20 (t, J=7.1 Hz, 2H), δ 2.44-2.60 (m, 1H), δ 2.70-2.82 (m, 1H), δ 5.47 (dd, J=54.2 Hz, J=5.8, 1H); 13C-NMR (75 MHz, CDCl3): δ 13.7, 14.2, 22.6, 23.1, 27.9, 29.9, 31.9, 41.4 (d, J=19.6 Hz), δ 91.2 (d, J=174 Hz): 19F-NMR (282 MHz, CDCl3): δ −179.08 (ddd, J=51.88 Hz, J=21.43 Hz, J=9.3 Hz). HRMS (EI+): exact mass calculated for C11H17FO requires m/z 184.1263, found 184.1255.

1. additionVar2 was added to the mixture at a final concentration of 2 μM
2. customThe mixture was split in 4.8 mL aliquots into 15 mL scintillation vials
3. customequipped with a stir bar
4. addition600 μL 10 mM NADPH in KPi buffer were added to each vial and
5. addition600 μL cofactor regeneration solution containing 500 mM glucose-6-phosphate and 10 units/mL glucose-6-phosphate dehydrogenase
6. additionwere then added to each vial
7. stirringThe resulting mixtures were stirred at room temperature
8. waitAfter 36 hours
9. customthe reaction mixtures
10. extractionextracted with chloroform (3×50 mL)
11. dry with materialThe organic phase was then dried over magnesium sulfate (MgSO4)
12. customevaporated in vacuo
13. customPurification of the resulting oil by silica gel chromatography (0-30% ethyl acetate/hexane)

ORD record

ord-5e29d76827194db09da255736c6b6b66

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08252559B2