Evidence for a concerted mechanism in a palladium trimethylenemethane cycloaddition Academic Article uri icon

abstract

  • 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.

citation count

  • 32

complete list of authors

  • Singleton, DA||Schulmeier, BE

publication date

  • January 1999