Aminium salts catalyzed rearrangement of α-pinene and β-ionone oxides

Abstract

β-ionone and α-pinene oxides 1, 3 isomerize rapidly and selectively to 1-(1,2,2-trimethylcyclopent-1-yl)-pent-2-en-1,4-dione 2 and the industrialy important 2,2,3-trimethyl-3-cyclopentene acetaldehyde 4. under the influence of catalytic amounts of aminium salts A,B. In order to find insights into the mechanism of our procedure, protic and Lewis acid-catalyzed rearrangements have also been reconsidered.