(4,4'-Di-tert-butyl-2,2'-bipyridine-κ²N¹,N^1')[bis[3,5-difluoro-2-(5-methyl-2-pyridinyl-κN)phenyl-κC¹]]iridium Hexafluorophosphate

• Piperidine
• 4-Methoxystyrene [M0130]
• (4,4'-Di-tert-butyl-2,2'-bipyridine)bis[2-(2',4'-difluorophenyl)-5-methylpyridine]iridium(III) Hexafluorophosphate (= Ir[dF(Me)(ppy)₂(dtbbpy)]PF₆) [B6254]
• Toluene
• 2,4,6-Triisopropylbenzenethiol

2,4,6-Triisopropylbenzenethiol (0.060 g, 0.25 mmol, 0.5 eq), piperidine (0.050 mL, 0.50 mmol, 1.0 eq), 4-methoxystyrene (0.10 mL, 0.75mmol, 1.5 eq), Ir[dF(Me)(ppy)₂(dtbbpy)]PF₆ (10 mg, 0.0099 mmol, 2.0 mol%) were dissolved in toluene (10 mL) at rt under N₂. The mixture was placed at a distance of 2-3 cm from Blue LED lamp with a cooling fan. The yellow orange suspension was stirred at rt under visible light irradiation until the amine was completely consumed. After 12 h of irradiation, the reaction mixture was diluted with ethyl acetate (20 mL) and extracted with 1 mol/L HCl aq. (70 mL x 2). The combined aqueous layer was washed with diethyl ether (30 mL x 2), then neutralized with 2 mol/L NaOH aq. (78 mL) to pH 7 and then saturated sodium bicarbonate aq. (10 mL) was added to ensure slightly basic conditions. The aqueous layer was extracted with dichloromethane (50 mL x 3). The combined organic layer was dried over sodium sulfate (30 g) for about 30 minutes and then filtered. The solvent was removed in vacuo to give compound 1 as a colorless oil (39 mg, y. 35%).

Toluene was degassed with nitrogen for 30 minutes before use.
Irradiation of visible light was performed with Kessil A160WE Tuna Blue 40Wx2.
The reaction mixture was maintained at rt by a cooling fan.
The reaction mixture was monitored by ¹H NMR and GC.

Compound 1

¹H NMR (400 MHz, CDCl₃); δ 7.12 (d, J = 7.8 Hz, 2H), 6.82 (d, J = 7.8 Hz, 2H), 3.78 (s, 3H), 2.79–2.75 (m, 2H), 2.56–2.49 (m, 6H), 1.46 (m, 4H), 1.25 (bs, 2H).

¹³C NMR (101 MHz, CDCl₃); δ 157.82, 132.58, 129.57, 113.75, 61.64, 55.22, 54.51, 32.62, 25.90, 24.37.

• Catalytic intermolecular hydroaminations of unactivated olefins with secondary alkyl amines
• A. J. Musacchio, B. C. Lainhart, X. Zhang, S. G. Naguib, T. C. Sherwood, R. R. Knowles, Science 2017, 355, 727.

• Anti-Markovnikov Hydroamination of Unactivated Alkenes with Primary Alkyl Amines
• D. C. Miller, J. M. Ganley, A. J. Musacchio, T. C. Sherwood, W. R. Ewing, R. R. Knowles, J. Am. Chem. Soc. 2019, 141, 16590.