تفاعل #218797

معادلة التفاعل

7-Benzyloxy-5-hydroxy-1,1-diisopropoxy-2,2,4,6-tetramethyl-heptan-3-one

pyridine

2,2,2-trichloroethyl chloroformate

→

32a

المردود 92.0%

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

المردود 92.0%

المذيبات

CH2Cl2

ظروف التفاعل

المعالجة

1. 1
   أخرىthe reaction mixture was quenched with brine
2. 2
   استخلاصextracted with CH2Cl2
3. 3
   تجفيفThe combined organic layers were dried over MgSO4
4. 4
   تركيزconcentrated under reduced pressure
5. 5
   أخرىThe crude product was purified by flash chromatography (gradient hexane to hexane/EtOAc 93:7)

الإجراء التجريبي

To a solution of 7-Benzyloxy-5-hydroxy-1,1-diisopropoxy-2,2,4,6-tetramethyl-heptan-3-one 32 (1.0 g, 2.4 mmol) and pyridine (0.8 mL, 7.3 mmol) in CH2Cl2 (10.0 mL) at 0° C. was added 2,2,2-trichloroethyl chloroformate (668.0 μL, 4.9 mmol) and the mixture was then allowed to warm to rt. After 1 h, the reaction mixture was quenched with brine and then extracted with CH2Cl2. The combined organic layers were dried over MgSO4 and concentrated under reduced pressure. The crude product was purified by flash chromatography (gradient hexane to hexane/EtOAc 93:7) to give 32a (1.285 g, 92%) as a clear oil: 1H NMR (400 MHz, CDCl3) δ 1.03-1.09 (m, 12H), 1.15 (d, J=1.8 Hz, 3H), 1.17 (d, J=1.9 Hz, 3H), 1.19-1.21 (m, 6H), 1.97-2.11 (m, 1H), 3.2 (dd, J=6.2 and 9.0 Hz, 1H), 3.54 (dd, J=4.8 and 9.1 Hz, 1H), 3.57-3.60 (m, 1H), 3.82 (qd, J=3.6 and 5.9 Hz, 2H), 4.47 (s, 2H), 4.57 (s, 1H), 4.72 (d, J=11.9 Hz, 1H), 4.81 (d, J=11.9 Hz, 1H), 5.08 (t, J=6.0 Hz, 1H), 7.29-7.35 (m, 5H); 13C NMR (100 MHz, CDCl3) δ 11.9, 15.0, 18.8, 21.4, 21.7, 22.3, 23.2, 23.4, 35.7, 42.5, 53.4, 53.9, 69.4, 70.9, 71.4, 73.3, 81.3, 94.7, 103.4, 127.5, 127.6, 128.2, 138.2, 154.0, 215.6; IR (film, NaCl, cm−1) 2966, 1760, 1698, 1247; LRMS (ESI) calcd for C27H41O7Cl3Na [M+Na+] 605.2, found 605.2; [α]23D=−20.4 (c=1.0, CHCl3.

المصدر