Synthesis of β-hydroxy esters from the ozonolysis of vinyl ethers

ORGN 109

David Soulsby, david_soulsby@redlands.edu, Department of Chemistry, University of Redlands, 1200 E. Colton Avenue, Redlands, CA 92373-0999
The ozonolysis of alkenes is a very powerful reaction which is widely used in organic chemistry. The majority of ozonolysis reactions provide either stable secondary ozonides or nucleophilic addition products. In 1985 Kuczkowski et al. demonstrated that the ozonolysis of ethyl vinyl ether in non-polar solvents occurs via an unusual mechanism whereby the carbonyl oxide undergoes preferential cycloaddition to the unreacted vinyl ether instead of the newly created formate ester to generate a 3-alkoxy-1,2-dioxolane. We have found that this reaction is broadly applicable to a range of substituted vinyl ethers, and that the in-situ acid catalyzed rearrangement of the dioxolane provides the substituted β-hydroxy esters in good yield. We have applied this methodology in our approach to the synthesis of the bruchin family, potent insect derived plant regulators. Finally, we have also shown that dioxolanes formed from racemic vinyl ethers undergo modest kinetic resolution to generate enantiomerically enriched β-hydroxy esters.