A suspension of 0.30 g (0.82 mmol) 6-bromo-4-methyl-3,4-dihydro-1H-pyrazino[1,2-a]indole-2-carboxylic acid tert-butyl ester, 0.29 g (3.3 mmol) copper(I)cyanide, 34.0 mg (0.030 mmol) tris(dibenzylideneacetone)dipalladium(0), 72.9 mg (0.013 mmol) 1,1′-bis(diphenylphosphino)ferrocene and 128.3 mg (0.82 mmol) tetraethylammonium cyanide in 6 ml dioxane was heated under reflux for 18 h. The reaction mixture was filtered, diluted with ethyl acetate and extracted with 10% aqueous citric acid, 10% aqueous sodium bicarbonate solution and brine. After drying over magnesium sulfate and filtration, the solvent was removed at a rotary evaporator and the residue was purified by chromatography on silica gel (0.032-0.063 mm) with n-hexane:ethyl acetate (9:1) as eluant to give the product as a light yellow foam. ISP-MS: m/e 312.2 ([M+H+]).
