Réaction #1747884

Équation de réaction

alcohol

(3S,4R)-4-tert-Butoxycarbonylamino-3-hydroxy-5-methylhexanoic Acid Methyl Ester

imidazole

tert-butyldimethylsilyl chloride

→

47

Rendement 98.0%

(3S,4R)-4-tert-Butoxycarbonylamino-5-methyl-3-(tert-butyldimethyl-silanyloxy)hexanoic Acid Methyl Ester

Rendement 98.0%

Solvants

DMF

Et2O

Conditions de réaction

Traitement

1. 1
   workup.WAITat room temperature for 18 h
2. 2
   AutreThe organic layer was separated
3. 3
   Lavagewashed with 10% HCl (50 mL), NaHCO3 (50 mL, sat) and NaCl (50 mL, sat)
4. 4
   Séchagedried (Na2SO4)
5. 5
   Filtrationfiltered
6. 6
   Concentrationconcentrated
7. 7
   AutreThe crude oil was purified by column chromatography (silica gel, EtOAc/Hexanes 1/9)

Mode opératoire

To a solution of the crude alcohol 46 (2.2 g, 7.9 mmol) in DMF (12 mL), under argon, cooled to 0° C., imidazole (1.61 g, 23.7 mmol) and tert-butyldimethylsilyl chloride (3.57 mL, 23.7 mmol) were added. The reaction mixture was stirred at 0° C. for 30 min and then at room temperature for 18 h and diluted with Et2O (50 mL). The organic layer was separated and washed with 10% HCl (50 mL), NaHCO3 (50 mL, sat) and NaCl (50 mL, sat), dried (Na2SO4), filtered, and concentrated. The crude oil was purified by column chromatography (silica gel, EtOAc/Hexanes 1/9) to yield 47 (2.59 g, 98%) as colorless oil. Rf 0.31 (EtOAc/Hexanes 1/9). [α]D20=+5.30 (c=1, CH2Cl2). 1H-NMR (500 MHz, CDCl3): 0.07 (s, 6H), 0.84-0.91 (m, 15H), 1.42 (s, 9H), 1.98-2.01 (m, 1H), 2.43 (dd, J=6.0 and 19 Hz, 1H), 2.52 (dd, J=5.9 and 18.5 Hz, 1H), 3.47-3.48 (m, 1H), 3.65 (s, 3H), 4.17-4.19 (m, 1H), 4.41-4.44 (m, 1H). 13C-NMR (125 MHz, CDCl3): −3.6, 16.6, 17.60, 18.9, 25.7, 27.8, 28.2, 39.9, 51.5, 51.9, 59.5, 70.19, 155.9, 172.2. IR (neat) 3373.1, 2960.7, 1717.0, 1504.6, 1366.1, 1173.0, 837.0. HRMS m/z cald for C19H39NO5Si (M+Na): 390.2675 found 390.2676.

Source