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TCI Practical Example: Protection of the Boronic Acid with 1,8-Diaminonaphthalene

We are proud to introduce the protection of boronic acid with 1,8-diaminonaphthalene.

Used Chemicals

• 3,5-Dibromophenylboronic Acid [D4670]
• 1,8-Diaminonaphthalene [D0102]
• Toluene

Procedure

To a reaction vessel, 1,8-diaminonaphthalene (1.5 g, 9.5 mmol), 3,5-dibromophenyl boronic acid (2.5 g, 8.9 mmol), toluene (30 mL) were subsequently added and refluxed for 2 hours. Consumption of the starting material was confirmed by TLC. The reaction mixture was cooled to room temperature and was filtered under reduced pressure. The solid was washed with toluene to obtain 1 (2.9 g, 81% yield) as a reddish white powder.

Experimenter’s Comments

The reaction mixture was monitored by TLC (hexane:ethyl acetate = 4:1, Rf = 0.5).

Analytical Data

Compound 1

¹H NMR (400 MHz, CDCl₃); δ 7.76 (t, 1H, J = 1.8 Hz), 7.67 (d, 2H, J = 1.8 Hz), 7.15 (m, 2H), 7.08 (m, 2H), 6.42 (d, 2H, J = 7.3 Hz), 5.94 (brs, 2H).

Lead Reference

• Flexible, Bowl-Shaped N-Heterocyclic Carbene Ligands: Substrate Specificity in Iridium-Catalyzed Ketone Hydrosilylation
• A. R. Chianese, A. Mo, D. Datta, Organometallics 2009, 28, 465.

Other Reference

• Boron-Masking Strategy for the Selective Synthesis of Oligoarenes via Iterative Suzuki−Miyaura Coupling
• H. Noguchi, K. Hojo, M. Suginome, J. Am. Chem. Soc. 2007, 129, 758.