Silica Sulfuric Acid: An Efficient Catalyst for the Direct Conversion of Primary and Secondary Trimethylsilyl Ethers to their Corresponding Ethers under Mild and Heterogeneous Conditions

Abstract

Primary and secondary trimethylsilyl ethers were converted to their corresponding ethers in the presence silica sulfuric acid with good to excellent yields under mild and heterogeneous conditions.

Keywords

silica sulfuric acid - silyl ethers - ethers - heterogeneous conditions

References

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Chemicals were purchased from Fluka, Merck and Aldrich chemicals companies. The products were characterized by comparison of their spectral (IR, ¹H NMR), TLC and physical data with the authentic samples. Silica sulfuric acid was synthesized according to the our previously reported procedure. [10a] All silyl ethers were synthesized according to the reported procedure. [13]

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Preparation of Silica Sulfuric Acid: A 500 mL suction flask was used. It was equipped with a constant-pressure dropping funnel containing chlorosulfonic acid (23.3 g, 0.2 mol) and gas inlet tube for conducting HCl gas over an adsorbing solution i. e. H₂O. Into it were charged 60.0 g of silica gel. Chlorosulfonic acid was added dropwise over a period of 30 min at r.t. HCl gas evolved from the reaction vessel immediately. After the addition was complete the mixture was shaken for 30 min. A white solid (silica sulfuric acid) 76.0 g was obtained. [10a]