Ethyl 6-oxo-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate → Ethyl 6-p-tolyl-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate

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Reaction Steps

The title compound was synthesized from ethyl 6-oxo-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate (0.3 g, 1.55 mmol, 1 equiv) and p-tolyl magnesium bromide (6.2 mL, 1M in THF, 6.2 mmol, 4 equiv) according to General Procedure 3 to give the endocyclic olefin-containing compound ethyl 6-p-tolyl-1,4-dihydrocyclopenta[b]pyrrole-2-carboxylate. 1H NMR showed a complex mixture but was qualitatively consistent with ethyl 6-p-tolyl-1,4-dihydrocyclopenta[b]pyrrole-2-carboxylate and the corresponding carbinol (ethyl 6-hydroxy-6-p-tolyl-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate) and was carried on to the next step without further purification. The mixture was hydrogenated according to General Procedure 6, and was purified by column chromatography (Isco CombiFlash) using a 0-30% gradient (EtOAc/Heptane) over 22 minutes. 0.1423 g. LCMS m/e 292 (M+Na). 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.33 (t, J=7.13 Hz, 3H), 2.30 (dt, J=8.65, 6.43 Hz, 1H), 2.34 (s, 3H), 2.61-2.70 (m, 1H), 2.75 (dd, J=8.79, 4.00 Hz, 1H), 2.86-2.97 (m, J=12.68, 8.41, 8.41, 4.03 Hz, 1H), 4.19-4.32 (m, 3H), 6.73 (d, J=1.61 Hz, 1H), 7.01-7.07 (m, 2H), 7.13 (d, J=7.86 Hz, 2H), 8.60 (br. s, 1H).

Provenance & Evidence