2,3,4,5-Tetrahydro-2,8-dimethyl-1H-pyrido[4,3-b]indole (30 mg, 0.15 mmol) was dissolved in DMF. Copper (I) iodide, L-proline (4 mg, 0.03 mmol) and potassium phosphate (63 mg, 0.29 mmol) were added and the reaction mixture was stirred for 10 min. at RT. 4-(1-bromo-3,3-dimethylbut-1-en-2-yl)pyridine (43 mg, 0.18 mmol) was added dropwise and the reaction mixture was purged with nitrogen. The reaction mixture was heated overnight at 85° C. (prolonged heating in some cases was required). DMF was evaporated under reduced pressure, the residue was diluted with water and the solid was filtered. The solid material was purified by silica gel chromatography (100-200 mesh) eluting with 0-7% MeOH-DCM. The product was further purified by HPLC. 1H NMR (CD3OD, freebase) δ (ppm): 8.21 (d, 2H), 7.15 (m, 3H), 7.05 (s, 1H), 6.94 (d, 1H), 6.80 (s, 1H), 3.90 (s, 2H), 3.18 (t, 2H), 2.90 (t, 2H), 2.70 (s, 3H), 2.36 (s, 3H), 1.30 (s, 9H).
