Thermal rearrangement of allyl vinyl ether: Heavy-atom kinetic isotope effects and the transition structure

Article abstract of DOI:10.1021/ja00067a009

Kinetic isotope effects (KIE) in the rearrangement of allyl vinyl ether (1, 3-oxa-1,5-hexadiene) to 4-pentenal (2) were measured for labeling with ¹⁴C at the 2-, 4-, and 6-positions and with ¹⁸O at the 3-position. BEBOVIB modeling calculations were applied successfully to the heavy-atom KIE and previously reported KIE for deuterium substitution at positions 4 and 6. From the calculations, it is deduced that the C₄-O bond is 50-70% broken and the C₁-C₆ bond 10-30% formed in the transition structure. Further, there is strong coupling between the allyl and vinyloxy fragments, strong bonding within the allyl but relatively weak bonding within the vinyloxy fragment.