تفاعل #218798

معادلة التفاعل

NaHCO3

32a

Carbonic acid 1-(2-benzyloxy-1-methylethyl)-5,5-diisopropoxy-2,4,4-trimethyl-3-oxopentyl Ester 2,2,2-trichloroethyl Ester

p-TsOH

→

67

المردود 76.0%

Carbonic Acid 1-(2-benzyloxy-1-methylethyl)-2,4,4-trimethyl-3,5-dioxopentyl Ester 2,2,2-trichloroethyl Ester

المردود 76.0%

المذيبات

THF H2O

ظروف التفاعل

المعالجة

1. 1
   استخلاصextracted with EtOAc
2. 2
   غسيلThe combined organic layers were washed with brine
3. 3
   تجفيفdried over MgSO4
4. 4
   تركيزconcentrated under reduced pressure
5. 5
   أخرىThe crude product was purified by flash chromatography (gradient hexane to hexane/EtOAc 84:16)

الإجراء التجريبي

To solution of 32a (1.28 g, 2.25 mmol) in 4:1 THF/H2O (25 mL) was added p-TsOH (111.0 mg, 0.6 mmol). After heating at 70° C. 5 h, the reaction mixture was poured into a cold (0° C.) sat. NaHCO3 aq solution (12 mL) and then extracted with EtOAc. The combined organic layers were washed with brine, dried over MgSO4 and concentrated under reduced pressure. The crude product was purified by flash chromatography (gradient hexane to hexane/EtOAc 84:16) to give 67 (793.2 mg, 76%) as a clear oil: 1H NMR (400 MHz, CDCl3) □ 0.90 (d, J=5.8 Hz, 3H), 1.0 (d, J=6.9 Hz, 3H), 1.24 (s, 6H), 1.97-2.04 (m, 1H), 3.24 (dd, J=4.8 and 9.2 Hz, 1H), 3.34 (m, 1H), 3.42 (dd, J=5.8 and 9.2 Hz, 1H), 4.35 (d, J=11.9 Hz, 1H), 4.39 (d, J=11.9 Hz, 1H), 4.64 (d, J=11.9 Hz, 1H), 4.69 (d, J=11.9 Hz, 1H), 4.96 (t, J=6.0 Hz, 1H), 7.19-7.28 (m, 5H), 9.49 (s, 1H); 13C NMR (100 MHz, CDCl3) −12.0, 14.8, 19.5, 19.6, 35.4, 43.3, 60.9, 71.1, 73.3, 80.37, 94.5, 127.7, 127.8, 128.3, 137.9, 154.1, 201.0, 210.1; IR (film, NaCl, cm−1) 2973, 2880, 1758, 1701, 1453, 1380, 1248; LRMS (ESI) calcd for C21H27O6Cl3Na [M+Na+] 503.0, found 503.0; [α]23D=−18.5 (c=0.8, CHCl3).

المصدر