Trifluoroacetic acid → trans-3-(3-Cyclopentoxy-4-methoxyphenyl)-4-methoxycarbonyl-1-(phenylmethyl)pyrrolidine

Participants

Reaction Steps

To a solution of N-methoxymethyl-N-(phenylmethyl)trimethylsilylmethylamine (2.84 g, 12 mmol) and (E)-methyl 3-(3-cyclopentoxy-4-methoxyphenyl)prop-2-enoate (2.76 g, 10 mmol) in 20 mL of CH2Cl2 cooled to 0° C. was added a 1 mL of a 1M solution of trifluoroacetic acid. Stirring was continued for 12 hr, and the solution was partitioned between ether and sat. NaHCO3. The layers were separated and the aqueous layer was extracted ethyl acetate (2×). The combined organic layers were dried (K2CO3), filtered, and concentrated under reduced pressure to a pale yellow oil. Chromatography on silica gel (3:1, hexanes:ethyl acetate) provided trans-3-(3-cyclopentoxy-4-methoxyphenyl)-4-methoxycarbonyl-1-(phenylmethyl)pyrrolidine (3.5 g, 86%) as a colorless oil. 1H-NMR (300 MHz): δ 2.74-3.09 (m, 5), 3.67 (s, 3), 3.81 (s, 3), 4.75 (m, 1).

Provenance & Evidence