n124662SE Academic Article uri icon


  • Carbon kinetic isotope effects were determined at natural abundance for the palladium trimethylenemethane cycloaddition of ester-amide 5. Substantial intermolecular 13C KIEs were observed for both olefinic carbons of 5. In contrast, a Michael addition to 5 exhibits a significant 13C KIE only at the carbon to the ester group. Intramolecular KIEs determined for the product-determining step(s) for reaction of the Pd-TMM intermediate would require a surprising isotope-dependent selection between diastereomeric ring closures. These results cannot be reconciled with a stepwise cycloaddition mechanism but are readily interpreted in terms of a concerted cycloaddition.

published proceedings

  • Journal of the American Chemical Society

author list (cited authors)

  • Singleton, D. A., & Schulmeier, B. E.

publication date

  • January 1, 1999 11:11 AM