Cleavage of aryl alkyl ethers with trimethylsilyl iodide

Lego · Sun Sep 04, 2005 3:25 am

Trimethylsilyl chloride is cheap, 500 ml about 35$, NaI is cheap, too

J. Org. Chem., 1979, 44( Cool

, 1247-1251
George A. Olah, Subhash C. Narang, B. G. Balaram Gupta, Ripudaman Malhotra
Synthetic methods and reactions. 62. Transformations with chlorotrimethylsilane/sodium iodide, a convenient in situ iodotrimethylsilane reagent

General Procedure for the Dealkylation of Ethers by Chlorotrimethylsilane/Sodium Iodide
These reactions were generally carried out in 20-mmol scale in a 50-mL flask fitted with a water condenser (if necessary) ;and flushed continuously with dry nitrogen. To a solution of the corresponding ether (20 mmol) and sodium iodide (3 g, 20 mmol) in acetonitrile (20 mL) was added chlorotrimethylsilane (2.16 g, 20 mmol) slowly with continuous stirring. The reaction mixture was stirred at room temperature until the completion of the reaction, as monitored by TLC on silica gel with hexane as eluent (see Table III). In some cases, it was necessary to heat the reaction mixture under reflux until the completion of the reaction. On completion of the reaction, the reactior, mixture was quenched with water (25 mL) and taken up in ether. The ether layer was then washed with sodium thiosulfate (to remove iodine) and brine and dried over Na2SO4. Evaporation of the ether layer gave pure phenolic products or, in the case of aliphatic ethers, alcohols and related products, depending on the reaction condit ions (see Table II for details). The products were further purified, if necessary, by column chromatography on silica gel by eluting successively with hexane to obtain pure iodides and with chloroform to obtain pur’e alcohols (see Table III).