Bromobenzene → rel-(1R,2S)-2-Phenylcyclohexanol

Participants

Reaction Steps

Magnesium turnings (706 mg; 29 mmol; 1.45 equiv.) were combined with THF (3.5 mL). Bromobenzene (3.1 mL; 29.4 mmol; 1.47 equiv.) in 5 mL of THF was added slowly dropwise. After approximately 1 mL of the bromobenzene solution had been added 1 drop of 1,2-dibromoethane was added to initiate the reaction. Once all the bromobenzene was added and the magnesium consumed the reaction mixture was diluted with THF (20 mL) and cooled to -30° Copper(I) chloride (130 mg; 1.32 mmol; 0.066 equiv.) was added and the reaction mixture was stirred for 10 min. A solution of cyclohexene oxide (2.1 mL; 20 mmol) in THF (2 mL) was added slowly dropwise. After the addition was complete the reaction mixture was warmed to 0° and stirred for 2 h. The reaction mixture was then treated with saturated aqueous ammonium sulfate (10 mL) and the layers were separated. The organic layer was washed with 5 mL portions of saturated ammonium sulfate until the washes were colorless. The combined aqueous washes were extracted with ether (3×10 mL), and the combined organic solution was dried (MgSO4) and concentrated. The crude product was recrystallized from pentane to afford 850 mg (24%) of 1m as white crystals. 1H nmr (300 MHz, CDCl3): 7.369-7.221 (5H, m); 3.640 (1H, m); 2.438 (1H, dt, J=10.43 Hz, 3.34 Hz); 2.146-2.114 (1H, m); 1.892-1.847 (2H, m); 1.788-1.753 (1H, m); 1.639 (1H, s); 1.530-1.254 (4H, m). IR (KBr, cm-1): 3500 (s); 2900 (s); 1600 (m). FDMS (m/e): 176 (M+).

Provenance & Evidence