반응 #494045

반응 방정식

(1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-benzyl 9-hydroxy-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysene-3a-carboxylate

PCC

→

(1R,3aS,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-benzyl 5a,5b,8,8,11a-pentamethyl-9-oxo-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysene-3a-carboxylate

수율 98.0%

용매

DCM

반응 조건

후처리

1. 1
   workup.STIRRINGThe mixture was further stirred for 5.5 h
2. 2
   여과The mixture was filtered through a pad of celite and silica gel which
3. 3
   세척was washed with dichloromethane
4. 4
   workup.ADDITIONa 1:1 mixture of ethyl acetate
5. 5
   농축The filtrate was concentrated under reduced pressure

실험 절차

To a solution of (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-benzyl 9-hydroxy-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysene-3a-carboxylate (7.1 g, 12.98 mmol) in DCM (100 mL) was added PCC (4.20 g, 19.48 mmol). After stirring for five minutes, the mixture turned a deep crimson color. The mixture was further stirred for 5.5 h. The mixture was filtered through a pad of celite and silica gel which was washed with dichloromethane and then a 1:1 mixture of ethyl acetate:hexanes. The filtrate was concentrated under reduced pressure to give (1R,3aS,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-benzyl 5a,5b,8,8,11a-pentamethyl-9-oxo-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysene-3a-carboxylate (6.92 g, 12.7 mmol, 98% yield) as a white foam. 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 0.78 (s, 3H), 0.89 (s, 3H), 0.94 (s, 3H), 0.95-1.73 (m, 17H), 1.01 (s, 3H), 1.05 (s, 3H), 1.67 (s, 3H), 1.82-1.94 (m, 3H), 2.21 (td, J=12.28, 3.51 Hz, 1H), 2.28 (dt, J=12.59, 3.17 Hz, 1H), 2.34-2.42 (m, 1H), 2.43-2.51 (m, 1H), 3.01 (td, J=10.99, 4.88 Hz, 1H), 4.59 (s, 1H), 4.72 (d, J=1.83 Hz, 1H), 5.06-5.17 (m, 2H), 7.28-7.38 (m, 5H).

출처