Syntheses of alpha,beta-unsaturated carbonyl compounds from the reactions of monosubstituted ozonides with stable phosphonium ylides

Ozonides derived from terminal alkenes reacted with 1.3 mol equiv. of stabl e phosphonium ylides to give (E)-alpha,beta -unsaturated carbonyl compounds in good to excellent yields. No reducing agent is needed in the reaction. However, alkoxyalkyl-substituted ozonides afforded a mixture of (Z)- and (E )-alpha,beta -unsaturated carbonyl compounds under similar condition. The E /Z isomeric ratio is affected by the position of the heteroatom in the subs tituent of the ozonides. The possible mechanism of this reaction will be di scussed. (C) 2000 Elsevier Science Ltd. All rights reserved.