Trifluoroacetic acid → (1S,2S)-2-(4-Hydroxy-phenyl)-cyclopropanecarboxylic acid ethyl ester

HRID 625683Notes

Reaction equation

HRID 625683 reaction equation
[CH2:1]([O:3][C:4]([C@H:6]1[CH2:8][C@@H:7]1[C:9]1[CH:14]=[CH:13][C:12]([O:15]C(C)(C)C)=[CH:11][CH:10]=1)=[O:5])[CH3:2].FC(F)(F)C(O)=O>>[CH2:1]([O:3][C:4]([C@H:6]1[CH2:8][C@@H:7]1[C:9]1[CH:10]=[CH:11][C:12]([OH:15])=[CH:13][CH:14]=1)=[O:5])[CH3:2]

Participants

3

Reactant 2

HCID 6422Trifluoroacetic acidHCID 72700304(1S,2S)-2-(4-tert-Butoxy-phenyl)-cyclopropanecarboxylic acid ethyl ester

Product 1

HCID 72700607(1S,2S)-2-(4-Hydroxy-phenyl)-cyclopropanecarboxylic acid ethyl esterYield 88.7%

Procedure

(1S,2S)-2-(4-tert-Butoxy-phenyl)-cyclopropanecarboxylic acid ethyl ester (10.5 g, 35.6 mmol) is dissolved in trifluoroacetic acid (15 mL, 196 mmol) and stirred for 5 minutes. The mixture is concentrated under vacuum, then re-evaporated five times from dichloromethane. The residue is dissolved in boiling cyclohexane (20 mL) and then allowed to cool. The cyclohexane layer is decanted off and the operation repeated. The residue is dried under vacuum to give the title compound (yield 6.51 g). GC (METHOD 1): tR=11.04 min; Mass spectrum (EI+): m/z=206 [M]+, e.e. 96% by chiral HPLC (Column: Daicel Chiralpak AS-H, 4.6×250 mm, 5 μm Mobile phase: hexane:ethanol 95:5, 1 mL/min, 25° C.) tR=14.17 (13.11) min.

Workup

  1. concentrationThe mixture is concentrated under vacuum
  2. customre-evaporated five times from dichloromethane
  3. dissolutionThe residue is dissolved
  4. temperatureto cool
  5. customThe cyclohexane layer is decanted off
  6. customThe residue is dried under vacuum

Sources & evidence

ORD record
ord-c79803df687a493fb1dce09cf8675fc0
Source dataset
uspto-grants-2016_04
Patent number
US09308194B2

Reaction notes

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