Butanal → tert-Butyl 8-butyryl-3,4-dihydropyrazino[1,2-a]indole-2(1H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a vial was added tert-butyl 8-bromo-3,4-dihydropyrazino[1,2-a]indole-2(1H)-carboxylate (1.4 g, 4.0 mmol), Pd(dba)2 (75 mg, 2 mol %), BINAP (75 mg, 3 mol %), and crushed 4 Å MS (2.0 g). The vial was evacuated and backfilled under argon. To the vial was then added DMF (15 mL), pyrrolidine (660 μL, 8.0 mmol), and butyraldehyde (1.0 mL, 12 mmol). The vial was then sealed under argon and heated to 115° C. for 6 h. The reaction mixture was then cooled to room temperature, diluted with EtOAc (50 mL), and filtered through celite. The filtrate was washed with H2O (50 mL) and brine (50 mL). The organic layer was dried over Na2SO4, filtered, and concentrated to afford a crude residue that was purified on silica gel (1:1 hexanes/EtOAc) to afford the title compound as a white solid (1.0 g, 73%).

Provenance & Evidence