Potassium Carbonate → Methyl 4-ethenyl-1H-pyrrole-2-carboxylate

Participants

Reaction Steps

Degas, by purging with nitrogen for 10 minutes, a solution of methyl 4-bromo-1H-pyrrole-2-carboxylate (2.0 g, 9.8 mmoles), triethenylboroxin pyridine (1.3 equiv; 3.1 g, 12.7 mmoles), and potassium carbonate (3 equiv; 4.1 g, 29.4 mmoles) in a mixture of 1,4-dioxane (20 mL) and water (10 mL). Add tris(dibenzylideneacetonyl)bis-palladium (Pd2(dba)3) (0.01 equiv; 0.0925 g, 98.0 μmoles) and 1,1′-bis(di-tert-butylphosphino)ferrocene (dtbpf) (0.03 equiv; 0.0853 g, 294.1 μmoles) and heat at 95° C. for 3 h. Cool to room temperature then partition between water (50 mL) and a 1:1 mixture of hexanes/diethyl ether (100 mL). The organic layer is washed with water (2×50 mL) then brine. Dry over Na2SO4, filter and evaporate to give methyl 4-ethenyl-1H-pyrrole-2-carboxylate as a straw colored oil (1.5 g). Use without further purification. 1H-NMR (CDCl3), δ: 8.90 (1H, br. s), 7.02 (1H, m), 6.95 (1H, m), 6.56 (1H, q) 5.48 (1H, dd), 5.05 (1H, dd), 3.86 (3H, s).

Provenance & Evidence