Angelic acid esters in the Ireland-Claisen rearrangement

CHED 522

Sarah Frost, sf145339@rc.hsu.edu and Martin J. Campbell, campbem@hsu.edu. Department of Chemistry, Henderson State University, 1100 Henderson Street, Arkadelphia, AR 71923
A series of allyl esters of angelic acid (Z-2-methyl-2-butenoic acid) was prepared from several allyl alcohols. The alcohols had various alkyl vinylic substituent patterns giving rise to 3-alkyl substituted propenyl angelate esters. These esters of a conjugated acid were subject to classical Ireland-Claisen conditions. The resulting 4-pentenoic acids had one or two quaternary stereocenters depending on the alcohol used. Various techniques were used to determine the stereochemistry of the rearrangement products.