Products > TCI Topics Archives > TCI Topics 2023 >

TCI Practical Example: Hartwig-Miyaura C-H Borylation Using an Iridium Catalyst

We are proud to present the C-H borylation of benzodithiophene using [Ir(cod)OMe]₂ as a catalyst. The direct borylation of aromatic compounds proceeds in combination with a catalyst and an electron-donating bpy ligand.

Used Chemicals

• Benzo[1,2-b:4,5-b']dithiophene [B3464]
• (1,5-Cyclooctadiene)(methoxy)iridium(I) Dimer (= [Ir(cod)OMe]₂) [C2662]
• 4,4'-Di-tert-butyl-2,2'-bipyridyl (= dtbpy) [D3134]
• Bis(pinacolato)diboron (= (pinB)₂) [B1964]
• Cyclohexane

Procedure

A solution of dtbpy (27 mg, 0.05 mmol), bis(pinacolato)diboron (1.0 g, 4.0 mmol) and [Ir(cod)OMe]₂ (33 mg, 0.025 mmol) in cyclohexane (40 mL) was stirred under nitrogen at room temperature for 10 minutes. Benzo[1,2-b:4,5-b']dithiophene (380 mg, 2.0 mmol) was added to the mixture and stirred at 80 ˚C for 18 hours. The reaction mixture was quenched with water and the two layers were separated, and then the water phase was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate and filtered. The solvent was removed under reduced pressure and the crude was washed with methanol (20 mL) to give 1 as a white solid (0.771 g, 87% yield).

Experimenter's Comments

The reaction mixture was monitored by NMR.
Cyclohexane was bubbled with nitrogen before use.

Analytical Data

Compound 1

¹H NMR (270 MHz, CDCl₃); δ 8.36 (s, 2H), 7.90 (s, 2H), 1.39 (s, 24H).

Lead Reference

• Synthesis and Transistor Application of Bis[1]benzothieno[6,7‑d:6′,7′‑d′]benzo[1,2‑b:4,5‑b′]dithiophenes
  • S. Nishinaga, H. Mori, Y. Nishihara. J. Org. Chem. 2018, 83, 5506.