Methanol → 1-(3',4'-Dichloro-2-fluorobiphenyl-4-yl)cyclopropane carboxylic acid 2-hydroxy-1-hydroxymethylethyl ester

Participants

Reaction Conditions

Reaction Steps

1-(3′,4′-Dichloro-2-fluorobiphenyl-4-yl)cyclopropane carboxylic acid oxiranylmethyl ester (1.0 g, 2.62 mmol) was dissolved in dry DCM (25 mL), and the solution was cooled at −20° C. To this solution 2,2,2-trifluoroacetic anhydride (1.46 mL, 10.49 mmol) in dry DCM (25 mL) was added, and the reaction mixture was kept at r.t. for 2 hours. All the volatile components were removed under reduced pressure, and traces of trifluoroacetic anhydride were removed by co-evaporation with toluene (2×100 mL) to afford crude 1-(3′,4′-dichloro-2-fluorobiphenyl-4-yl)cyclopropanecarboxylic acid 2-(2,2,2-trifluoro-acetoxy)-1-(2,2,2-trifluoro-acetoxymethyl)ethyl ester (1.4 g, 2.368 mmol) as a colourless oil. 1-(3′,4′-Dichloro-2-fluorobiphenyl-4-yl)cyclopropanecarboxylic acid 2-(2,2,2-trifluoro-acetoxy)-1-(2,2,2-trifluoro-acetoxymethyl)ethyl ester (0.9 g, 1.522 mmol) was dissolved in a mixture of pentane/CH2Cl2 (3/1 v/v; 10 mL), and the solution was cooled at −20° C. To this solution, pyridine (1.231 mL, 15.22 mmol) and methanol (0.925 mL, 22.83 mmol) dissolved in a mixture of pentane/DCM (3/1 v/v; 10 mL) were added. The reaction mixture was allowed to warm to r.t. and stirred at r.t. for 1 hour and 45 minutes. The solvent was removed under reduced pressure, and the residue was dried under vacuum for 1 hour to obtain crude 1-(3′,4′-dichloro-2-fluorobiphenyl-4-yl)cyclopropane carboxylic acid 2-hydroxy-1-hydroxymethylethyl ester (0.61 g, quantitative yield) which was used as such in the next reaction.

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