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TCI Practical Example: Palladium(II) Acetate-catalyzed Heck Reaction

We are proud to present the Heck cross coupling using palladium(II) acetate as a catalyst.

Used Chemicals

• 4-Bromophenol [B0787]
• Styrene (stabilized with TBC) [S0095]
• Palladium(II) Acetate (Purified) [P2161]
• Tri(o-tolyl)phosphine [T1024]
• Triethylamine [T0424]

Procedure

To a solution of 4-bromophenol (1.5 g, 8.7 mmol) in triethylamine (10 mL), styrene (1.1 g, 10.8 mmol), tri(o-tolyl)phosphine (0.16 g, 0.52 mmol) and palladium(II) acetate (0.020 g, 0.087 mmol) were successively added at room temperature. The reaction mixture was stirred overnight at 100 °C under nitrogen atmosphere. To a 1 mol/L HCl aq. (100 mL) the reaction mixture was added below 15 °C. Then diethyl ether (100 mL) was added and the mixture was stirred for 10 min. The solution was partitioned and the water phase was extracted by diethyl ether (50 mL). Then combined organic layer was dried over sodium sulfate and filtered. The residue was recrystallized from toluene giving trans-4-hydroxystilbene as a pale brown solid (0.97 g, 57% yield).

Experimenter's Comments

The reaction mixture was monitored by ¹H NMR.

Analytical Data

trans-4-Hydroxystilbene

¹H NMR (400 MHz, CDCl₃); δ 9.59 (s, 1H), 7.53 (d, J = 7.3 Hz, 2H), 7.42 (d, J = 8.2 Hz, 2H), 7.34 (dd, J = 7.8, 7.3 Hz, 2H), 7.22 (t, J = 7.3 Hz, 1H), 7.15 (d, J = 16.5 Hz, 1H), 7.01 (d, J = 16.5 Hz, 1H), 6.77 (d, J = 8.7 Hz, 2H).

¹³C NMR (101 MHz, CDCl₃); δ 157.3, 137.6, 128.7 (2 C), 128.5, 128.1, 127.9 (2 C), 127.0, 126.1 (2 C), 125.1, 115.6 (2 C).

Lead Reference

• Palladium-catalyzed vinylic substitution with highly activated aryl halides
• C. B. Ziegler Jr., R. F. Heck, J. Org. Chem. 1978, 43, 2946.

Other Reference

• Advances in the Heck chemistry of aryl bromides and chlorides
• N. J. Whitcombe, K. K. Hii, S. E. Giboson, Tetrahedron 2001, 57, 7449.