Triethylamine → (2S,4R)-1-Phenyl-4-(2-trifluoromethyl-benzenesulfonyl)-pyrrolidine-2-carboxylic Acid Methyl Ester

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Reaction Steps

To a solution of (2S,4R)-4-(2-trifluoromethyl-benzenesulfonyl)-pyrrolidine-2-carboxylic acid methyl ester (see example xx) (1.03 g, 1.0 eq) in dry dichloromethane (25 mL) were added freshly powdered molecular sieves (2.88 g). Phenyl boronic acid (0.74 g, 2.0 eq) was added, followed by triethylamine (0.62 g, 2.0 eq) and copper(II)acetate (0.61 g, 1.1 eq). Oxygen gas was bubbled through the reaction mixture for 5 min. The flask was sealed with a rubber septum and left under an atmosphere of oxygen by means of a balloon. After stirring at room temperature for 24 h, the mixture was filtered and the filtrate was treated with water and filtered again. The phases were separated and the organic phase dried over sodium sulfate, filtered and evaporated. Purification by flash chromatography on silica gel with an heptane/ethyl acetate gradient yielded the title compound as a light yellow solid (0.23 g, 18%). MS (ESI): m/z=414.2 [M+H]+.

Provenance & Evidence