Sodium Carbonate → tert-butyl 4-(benzofuran-3-yl)-5,6-dihydropyridine-1(2H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of commercially available 3-bromobenzofurane (2.50 g, 12.7 mmol) and commercially available tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate (4.32 g, 14.0 mmol) in 1,2-dimethoxyethane (85 ml) and 2M sodium carbonate solution (21.1 ml, 42.3 mmol) was purged with argon in an ultrasonic bath during 5 min. Then triphenylphosphine (666 mg, 2.54 mmol) and palladium(II)acetate (285 mg, 1.27 mmol) were added and the reaction mixture was allowed to stir at 85° C. for 17 h. The reaction mixture was cooled to room temperature, poured into water (30 ml) and extracted with diethyl ether (2×120 ml). The combined organic layers were washed with brine (60 ml), dried (MgSO4) and evaporated. The crude product (5.78 g) was further purified by flash chromatography on silica gel (heptane/ethyl acetate 4:1) to yield tert-butyl 4-(benzofuran-3-yl)-5,6-dihydropyridine-1(2H)-carboxylate as a yellow oil (2.06 g, 54%), MS (ISP) m/z=300.2 [(M+H)+].

Provenance & Evidence