Iron(III) Tosylate in the Preparation of Dimethyl and Diethyl Acetals from Ketones and β-Keto Enol Ethers from Cyclic β-Diketones

Abstract

An efficient method for conversion of ketones to their corresponding dimethyl and diethyl acetals and of cyclic β-diketones into β-keto enol ethers using Fe(OTs)₃ as a catalyst is described.

Keywords:

• Diethyl acetals
• dimethyl acetals
• iron(III) tosylate
• β-keto enol ethers
• ketones

Notes

^a The structures of the products were established from their spectral (¹H NMR, ¹³C NMR, and MS) data.

^a The structures of the products were established from their spectral (¹H NMR, ¹³C NMR, and MS) data.

^b Yield of bis-acetal at C₁ and C₄.

^c Only miniscule amounts of the corresponding enol ether were detected.

^d 5 mol% of Fe(OTs)₃ was used.

^e Yield based on conversion in parentheses.

^f Acetal/Ethyl(2E)-3-ethoxy-2-butenoate.

^a The structures of the products were established from their spectral (¹H NMR, ¹³C NMR, and MS) data.

^b Unless otherwise stated, alcohol acts as solvent.

^c In toluene.

^d In 1,2-dichloroethane.

^e β-Ketodioxolane 5/β-keto enol ether 6.

^f β-Keto enol ether 7.

^g β-Keto enol ether 8/bis-β-keto enol ether 9.

^h Bis-β-keto enol ether 10. Only minimal amounts of the corresponding β-keto enol ether was isolated (0.9%).