反应详情

温度

25 °C

Styrene (1 g, 9.6 mmol) was taken with 100 mg Immobilized lipase and 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid monohydrate (0.3 g, 1.03 mmol) in dry dichloromethane (15 mL) and stirred at 25° C. and added urea hydrogen peroxide (3 g, 32 mmol) portion-wise at a pH 5 for 20 hours. The reaction was monitored occasionally on TLC. The mixture was filtered and washed the residue with dichloromethane and the filtrate was reduced its volume under reduced pressure using vacuum flash evaporator. The product was purified by preparative TLC with 40% CH2Cl2/hexane. Yield: 70%; oil (Found: C, 79.91; H, 6.65. C8H8O requires C, 79.97; H, 6.71%); Rf (40% CH2Cl2/hexane) 0.55. The enantiomeric excess was determined by HPLC analysis using a Chiralcel OD column [iPrOH:hexane=0.2:99.8, flow rate 0.2 cm3 min−1], [α]D22+21.6 (c 0.7, PhH) 48% ee; {lit., [α]D22+44.8 (c 1.00, PhH), R}; νmax (neat/cm−1) 1496, 1476, 1452, 1390; δH (300 MHz; CDCl3) 2.80 (1H, dd, J 2.6 and 5.5, HCOCHH), 3.13 (1H, dd, J 4.1 and 5.5, HCOCHH), 3.85 (1H, dd, J 2.6 and 4.0, PhCHOCH2), 7.26-7.36 (5H, m, 5×CH, arom.); δC (300 MHz; CDCl3) 51.7 (CH2), 52.8 (CH), 125.9, 126.3, 128.6, 128.9 and 138.0 (6×C-Ph). MS m/z (rel. intensity %): 122 (M+2, 15), 121 (M+1, 43), 120 (M+, 20), 105(100), 91(68), 77 (88).

1. filtrationThe mixture was filtered
2. washwashed the residue with dichloromethane
3. customvacuum flash evaporator
4. customThe product was purified by preparative TLC with 40% CH2Cl2/hexane