Boron trifluoride etherate → (2S,5R/S)-5-Allyl-1-(tert-butoxycarbonyl)pyrrolidine-2-carboxylic acid tert-butyl ester

HRID 884388Notes

Reaction equation

HRID 884388 reaction equation
[C:1]([O:5][C:6]([C@@H:8]1[CH2:12][CH2:11][CH:10](OCC)[N:9]1[C:16]([O:18][C:19]([CH3:22])([CH3:21])[CH3:20])=[O:17])=[O:7])([CH3:4])([CH3:3])[CH3:2].[CH2:23]([Si](C)(C)C)[CH:24]=[CH2:25].B(F)(F)F.CCOCC.C([O-])(O)=O.[Na+]>C(Cl)Cl.CC(OC)(C)C>[C:1]([O:5][C:6]([C@@H:8]1[CH2:12][CH2:11][CH:10]([CH2:25][CH:24]=[CH2:23])[N:9]1[C:16]([O:18][C:19]([CH3:20])([CH3:21])[CH3:22])=[O:17])=[O:7])([CH3:2])([CH3:3])[CH3:4]

Participants

7

Reactant 4

HCID 8000Boron trifluoride etherateHCID 69808AllyltrimethylsilaneHCID 516892Sodium BicarbonateHCID 123363996(2S,5R/S)-1-(tert-Butoxycarbonyl)-5-ethoxypyrrolidine-2-carboxylic acid tert-butyl ester

Product 1

HCID 57558972(2S,5R/S)-5-Allyl-1-(tert-butoxycarbonyl)pyrrolidine-2-carboxylic acid tert-butyl esterYield 77.3%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 15413tert-Butyl methyl etherSolvent

Procedure

A solution of 12.6 g of the α-methoxycarbamate 45 (40.0 mmol) and 16.0 ml of allyltrimethylsilane (100 mmol, 2.5 eq.) in 100 ml of anhydrous CH2Cl2 was cooled to −78° C. and added dropwise with 10.1 ml of BF3.OEt2 (80.0 mmol, 2 eq.). After completed addition, stirring was continued for 30 min, and completion of the reaction was checked by means of TLC (EE/CH 1:9). Thereafter, 10 ml of a saturated NaHCO3 solution was added, and the batch was allowed to come to RT. After transferring into a separating funnel together with 200 ml of MTBE, the phases were separated and the aqueous phase was extracted with 2×100 ml of MTBE. The combined organic phases were washed with 100 ml of half-conc. NaCl solution, dried over MgSO4 and concentrated. The residue was purified using silica gel column chromatography (EE/CH 1:9), thereby obtaining 9.62 g of allyl substitution product 46 (30.9 mmol, 77%) as a colorless oil (mixture of epimers, cis/trans 75:25).

Workup

  1. additionaddition
  2. customto come to RT
  3. customthe phases were separated
  4. extractionthe aqueous phase was extracted with 2×100 ml of MTBE
  5. washThe combined organic phases were washed with 100 ml of half-conc
  6. dry with materialNaCl solution, dried over MgSO4
  7. concentrationconcentrated
  8. customThe residue was purified

Sources & evidence

ORD record
ord-b483acaf978f4eba8f3374c50c6e0f56
Source dataset
uspto-grants-2012_08
Patent number
US08242105B2

Reaction notes

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