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Silyl protection of a phenol; (4-bromophenoxy)(tert-butyl)dimethylsilane

SyntheticPage 429
DOI: 10.1039/SP429
Submitted Jul 04, 2010, published Jul 08, 2010
Christopher Cooksey (
A contribution from QUINTOX group

			Reaction Scheme: Silyl protection of a phenol

Chemicals Used

tert-butyl(chloro)dimethylsilane (Aldrich)

4-Bromophenol (Aldrich)

Imidazole  (Aldrich)

Dimethylformamide (Aldrich)


4-Bromophenol and imidazole were dried in a dessicator over P2O5. tert-Butyl(chloro)dimethylsilane (15.0 g, 0.1 mol) was added to a solution of 4-bromophenol (12.1 g, 0.07 mol) and imidazole (16.5 g, 0.24 mol) in dimethylformamide (50 cm3) and the mixture was magnetically stirred (2 d). Water (5 cm3) and 60/80 petrol (50 cm3) were then added, followed after 1 h by more water (100 cm3). The phases were separated and the aqueous phase extracted twice with 1: 1 60/80 petrol-diethyl ether (100 cm3). The combined organic phases were washed successively with water, aqueous NaOH solution (1 M), water and saturated NaCl solution and dried (MgSO4). The solution was evaporated and the residue distilled to give a colourless oil, 19.8 g (98%), b.p. 67-68 ºC/0.01 mm.

Author's Comments

This well documented reaction proceeded without problems. The literature yield was 90%.


δH  (CDCl3, 60 MHz), 7.13d (2 H), 6.25d (2H), 0.93s (9 H), 0.16s (6 H).

δC (CDCl3, 100 MHz), 154.78, 132.26, 121.68, 113.60, 25.61, 18.16, -4.50.

Lead Reference

Riley PA, Cooksey CJ, Johnson CI, Land EJ, Latter AM, Ramsden CA., Eur J Cancer, 1997, 33(1), 135-143. PubMed PMID: 9071913. doi: 10.1016/S0959-8049(96)00340-1

Other References

Angle, SR, Louie, MS,  J. Org. Chem., 1991, 56(8), 2853-2866. doi: 10.1021/jo00008a049

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Keywords: phenol, protection, silylation

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