Propyne → Methyl 3-prop-1-ynyl-1-benzofuran-5-carboxylate

Participants

Reaction Steps

Methyl 3-bromobenzofuran-5-carboxylate (750 mg, 2.94 mmol) is combined with bis(benzonitrile)palladium dichloride (169 mg, 0.44 mmol), cuprous iodide (19 mg, 0.10 mmol), tri-t-butylphosphine ((10% in hexane) 1.92 ml, 0.95 mmol), and propyne (2 ml, 35 mmol) in 7 ml dry dioxane in 15 ml screw cap pressure tube under nitrogen. The mixture is treated with DIA (494 μL, 3.6 mmol), is stirred overnight at RT, and is diluted with 50 ml EtOAc. The reaction is washed with 4×25 ml 1:1:0.1 H2O/brine/conc. NH4OH, the organic layer is dried (MgSO4), and the volatiles are removed in vacuo. The crude material is chromatographed over 50 g silica gel (230-400 mesh) eluting with 12% EtOAc/hexane. The appropriate fractions are combined and concentrated to give 460 mg (73%) of methyl 3-prop-1-ynyl-1-benzofuran-5-carboxylate as a pale solid. MS for C13H10O3 (EI) m/z (rel. intensity): 214 (M)+.

Provenance & Evidence