(3S,4S)-Methyl 4-(4-chlorophenyl)-1-methylpiperidine-3-carboxylate → (3S,4R)-4-(4-Chloro-phenyl)-1-methyl-piperidine-3-carboxylic acid methyl ester

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Reaction Steps

Concentration of the mother liquor from Example 1 gave a mixture of compounds 1 and 2. Flash chromatography on silica gel using ether/Et3N 9/1 as eluent gave compound 2 (2.0 g, 18%): 1H NMR (benzene-d6) δ—1.4-1.5 (m, 1H), —1.62 (dq, 1H, J=3.9 and 12.6 Hz), 1.75 (dt, 1H, J=2.7 and 12.0 Hz), 2.06 (s, 3H), 2.0-2.15 (m, 1H), 2.54-2.63 (m, 1H), 2.68 (dt, 1H, J=4.2 and 11.7 Hz), 2.86-3.0 (m, 2H), 3.08 (s, 3H), 6.87 (d, 2H, J=8.7 Hz), 7.07 (d, 2H, J=8.7 Hz); 13C NMR (CDCl3) δ 33.1, 44.0, 46.1, 49.1, 51.5, 55.7, 58.1, 128.6, 128.7, 132.3, 141.9, 173.4; MS m/z (%) 267 (M+, 17), 208 (30), 128 (16), 114 (16), 43 (100).

Provenance & Evidence