Reaktion #7771

Reaktionsgleichung

NH4Cl

BF3 Et2O

(±)(1S*,2R*,4S*)-4-(benzyloxy)-1,2-epoxycyclohexane

1-Methanesulfonyl-4-methylsulfanyl-benzene

nBuLi

→

(±)(1R*,2R*,5S*)-5-benzyloxy-2-(4-methylsulfanyl-benzenesulfonylmethyl)-cyclohexanol

Ausbeute 80.3%

Lösungsmittel

THF

EtOAc

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONAfter an addition 1 h at −78° C.
2. 2
   Temperaturthe solution was warmed to 0° C
3. 3
   workup.WAITAfter 2 h
4. 4
   Temperaturthe solution was cooled to −78° C.
5. 5
   TemperaturThe solution was warmed to rt
6. 6
   WaschenThe organic layer was washed with brine
7. 7
   Sonstigedried
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated

Vorschrift

1-Methanesulfonyl-4-methylsulfanyl-benzene (3.25 g) was dissolved in THF (50 mL) and cooled to −78° C. prior to the addition of 1.6 M nBuLi (10 mL). After 0.5 h, BF3-Et2O (2.04 mL) was added followed by (±)(1S*,2R*,4S*)-4-(benzyloxy)-1,2-epoxycyclohexane (2.19 g) (Chini et al. J. Org. Chem. 1990, 55, 4265) in THF (20 mL). After an addition 1 h at −78° C., the solution was warmed to 0° C. After 2 h, the solution was cooled to −78° C. and saturated NH4Cl solution (aq) was added. The solution was warmed to rt and EtOAc was added. The organic layer was washed with brine, dried, filtered, and concentrated. Flash chromatography of the resulting residue gave (±)(1R*,2R*,5S*)-5-benzyloxy-2-(4-methylsulfanyl-benzenesulfonylmethyl)-cyclohexanol (3.5 g) as the major product: 1H NMR (CDCl3, δ ppm, 300 mHz) 1.41 (m, 2H), 1.59 (m, 1H), 1.95 (m, 1H), 2.05-2.35 (m, 2H), 2.54 (s, 3H), 2.96 (dd, 1H), 3.64 (m, 2H), 3.81 (s, 1H), 4.48 (m, 2H), 7.3 (m, 7H), 7.82 (d, 2H)

Quelle