Tolylboronic acid → 9-(4-methylphenyl)-2,3,4,4a,5,6-hexahydro-1H-pyrazino[1,2-a]quinoxaline

Participants

Reaction Conditions

Reaction Steps

To a two-necked round bottom flask charged with argon was added palladium (II) acetate (4 mg, 0.0195 mmol), 2-dicyclohexylphosphino-2′-(N,N-dimethylamino)biphenyl (10 mg, 0.02925 mmol), p-tolylboronic acid (80 mg, 0.59 mmol), potassium fluoride (68 mg, 1.17 mmol), and 9-Chloro-3-carbobenzyloxy-2,3,4,4a,5,6-hexahydro-1H-pyrazino[1,2-a]quinoxaline (140 mg, 0.39 mmol). 1 ml of degassed 1,4-dioxane was added and the reaction was degassed and heated to 100° C. for 20 h. The reaction mixture was cooled to rt and diluted with ether. 1N NaOH was added and the aqueous layer was extracted with ethyl acetate. The combined organics were washed with brine, dried over MgSO4, and concentrated to a yellow residue. The crude material was purified by radial PLC (1 mm plate, load with methylene chloride, elute with 20-40% ethyl acetate/hexanes) to give 9-(4-methylphenyl)-2,3,4,4a,5,6-hexahydro-1H-pyrazino[1,2-a]quinoxaline as a yellow foam (0.23 mmol, 60%).

Provenance & Evidence