反应详情

To an argon-flushed flask containing 2.32 g (8 mmol) of 4'-hydroxy-4-biphenylyl benzoate and 1.25 eq of triphenylphosphine in 200 ml of dry THF was added a solution of 1.052 g (8.08 mmol) of (R)-2-octanol dissolved in 15 ml of dry THF via syringe. Then 1.2 eq of diethyl azodicarboxylate in 30 ml of dry THF was added dropwise over 30 min. The reaction mixture was stirred at room temperature for 20 h and then 5 drops of water was added and stirring was continued for an additional 1 h. The solvent was evaporated and the crude product was triturated for 1 h in a mixture of hexanes/ethyl acetate [70/30]. The solution was filtered through a short silica gel pad and the solvent evaporated. Flash chromatography on silica gel using hexanes/ethyl acetate [98/2] as eluent afforded 2.42 g (75%) of (S)-4'-(1-methylheptyloxy)-4-biphenylyl benzoate (Compound 39, Scheme VIII, R2 =(S) --OCH(CH3)C6H13) as a white solid (mp. 84° C.); Rf [hexanes/ethyl acetate 95/5]: 0.34; 1H NMR (300 MHz, CDCl3): δ0.89 (t, 3H, J=6.8 Hz), 1.14-1.68(m, 9H), 1.32(d, 3H, J=6.1 Hz), 1.75 (m, 1H), 4.39 (m, 1H), 6.95(d, 2H, J=9 Hz), 7.25(d,2H, J=8.4 Hz), 7.46-7.68(m, 7H), 8.22 (dd, 2H, J=1.2 Hz J=6.9 Hz); 13C NMR (300 MHz, CDCl3): δ14.02, 19.73, 22.55, 25.50, 29.24, 31.75, 36.48, 73.96, 116.10, 121.88 , 127.72, 128.58, 129.61, 130.21, 132.64, 133.59, 138.79, 149.87, 157.94, 165.30; IR (CHCl3): 3020, 2930, 2850, 1745, 1600, 1500, 1260, 1240, 1170, 1190, 1070, 1000, 840, 820 cm-1 ; Mass spectrum, m/z (rel. intensity): 402(M+ 16), 290(14), 105(100), 77 (16), 43 (6) .

1. customTo an argon-flushed flask
2. stirringstirring
3. waitwas continued for an additional 1 h
4. customThe solvent was evaporated
5. customthe crude product was triturated for 1 h in a mixture of hexanes/ethyl acetate [70/30]
6. filtrationThe solution was filtered through a short silica gel pad
7. customthe solvent evaporated