Lithium Chloride → Ethyl 5-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(benzoyloxymethyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)isoxazole-3-carboxylate

HRID 406888Notes

Reaction equation

HRID 406888 reaction equation
C([Sn](CCCC)(CCCC)[C:6]1[O:10][N:9]=[C:8]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[CH:7]=1)CCC.[C:24]([O:32][CH2:33][C@:34]12[CH2:67][CH2:66][C@@H:65]([C:68]([CH3:70])=[CH2:69])[C@@H:35]1[C@@H:36]1[C@@:49]([CH3:52])([CH2:50][CH2:51]2)[C@@:48]2([CH3:53])[C@@H:39]([C@:40]3([CH3:64])[C@@H:45]([CH2:46][CH2:47]2)[C:44]([CH3:55])([CH3:54])[C:43](OS(C(F)(F)F)(=O)=O)=[CH:42][CH2:41]3)[CH2:38][CH2:37]1)(=[O:31])[C:25]1[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=1.[Cl-].[Li+]>O1CCOCC1.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[C:24]([O:32][CH2:33][C@:34]12[CH2:67][CH2:66][C@@H:65]([C:68]([CH3:70])=[CH2:69])[C@@H:35]1[C@@H:36]1[C@@:49]([CH3:52])([CH2:50][CH2:51]2)[C@@:48]2([CH3:53])[C@@H:39]([C@:40]3([CH3:64])[C@@H:45]([CH2:46][CH2:47]2)[C:44]([CH3:54])([CH3:55])[C:43]([C:6]2[O:10][N:9]=[C:8]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[CH:7]=2)=[CH:42][CH2:41]3)[CH2:38][CH2:37]1)(=[O:31])[C:25]1[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=1

Participants

6

Reactant 3

HCID 433294Lithium ChlorideHCID 2763256Ethyl 5-(tributylstannyl)-1,2-oxazole-3-carboxylateHCID 86666260HCID 86666260, compound

Product 1

HCID 67777149Ethyl 5-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(benzoyloxymethyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)isoxazole-3-carboxylateYield 20.3%

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 312751,4-DioxaneSolvent

Conditions

Temperature
85 °C

Procedure

To a sealable vial containing ethyl 5-(tributylstannyl)isoxazole-3-carboxylate (0.052 g, 0.122 mmol) was added ((1R,3aS,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-9-(trifluoromethylsulfonyloxy)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-3a-yl)methyl benzoate (0.075 g, 0.111 mmol), lithium chloride (0.014 g, 0.332 mmol), and tetrakis(triphenylphosphine)palladium(0) (6.40 mg, 5.54 μmol). The mixture was diluted with 1,4-Dioxane (2 mL) and was flushed with N2. The vial was sealed and heated to 85° C. After 15.5 h of heating, the mixture was cooled to rt, was diluted with water (4 mL), and was extracted with dichloromethane (3×4 mL). The combined organic layers were dried over Na2SO4. The drying agent was removed by filtration and the filtrate was concentrated under reduced pressure. The residue was purified by Biotage flash chromatography using a 0-10% EtOAc in hexanes gradient. The fractions containing the expected product were combined and concentrated under reduced pressure. Ethyl 5-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(benzoyloxymethyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)isoxazole-3-carboxylate was isolated as an off-white foam (0.015 g total mass, 0.022 mmol, 20.3% yield). LCMS: m/e 668.53 (M+H)+, 3.11 min (method 1).

Workup

  1. customwas flushed with N2
  2. customThe vial was sealed
  3. temperatureAfter 15.5 h of heating
  4. temperaturethe mixture was cooled to rt
  5. additionwas diluted with water (4 mL)
  6. extractionwas extracted with dichloromethane (3×4 mL)
  7. dry with materialThe combined organic layers were dried over Na2SO4
  8. customThe drying agent was removed by filtration
  9. concentrationthe filtrate was concentrated under reduced pressure
  10. customThe residue was purified by Biotage flash chromatography
  11. additionThe fractions containing the expected product
  12. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-ca74c13023ec4048a979d625329b9c0d
Source dataset
uspto-grants-2014_06
Patent number
US08754068B2

Reaction notes

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