Реакция #218802

Уравнение реакции

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

pyridine

2,2,2-trichloroethyl chloroformate

→

desired product

Выход 92.0%

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

Выход 92.0%

Растворители

CH2Cl2

Условия реакции

Обработка

1. 1
   Другоеthe reaction mixture was quenched with brine
2. 2
   Экстракцияextracted with CH2Cl2
3. 3
   СушкаThe combined organic layers were dried over MgSO4
4. 4
   Концентрированиеconcentrated under reduced pressure
5. 5
   ДругоеThe crude product was purified by flash chromatography (gradient hexane to hexane/EtOAc 93:7)

Методика

To a solution of 7-Benzyloxy-5-hydroxy-1,1-diisopropoxy-2,2,4,6-tetramethyl-heptan-3-one (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 the desired product (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.

Источник