tert-Butyl hydroperoxide → (2S,3R)-1,2-Epoxy-2-(2,4-difluorophenyl)butan-3-ol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of diethyl L(+)-tartrate (8 ml, 0.047 mole) in dry CH2Cl2 (1.2 L) is added activated 3A° molecular sieve powder (300 g) and cooled the mixture to -5 ° C. Added a solution of titanium (IV) isopropoxide (30 ml, 0.10 mole) followed by t-butyl hydroperoxide (78 ml of 5-6M solution in decane) and continue to stir at -5° C. for 25 minutes. To this mixture, a solution of crude 6b, in CH2Cl2 (100 ml) is added and stirred for 12 hours at 5° C. Cooled the reaction mixture to -40° C., added 70 ml of 30% aq. NaOH solution saturated with NaCI and the mixture is allowed to warm to 10° C. Added 60 g of MgSO4, 20 g of celite and continued to stir at 10° C. for 30 minutes. The mixture is suction-filtered over celite. To the filtrate toluene (1 L), and 700 ml of ether are added and insoluble material removed by filtration. The filtrate is evaporated under reduced pressure to give the crude 7c as a light brown oil.

Herkunft & Nachweise