Isotope effects and heavy-atom tunneling in the Roush allylboration of aldehydes.

ABSTRACT: Intermolecular (13)C kinetic isotope effects (KIEs) for the Roush allylboration of p-anisaldehyde were determined using a novel approach. The experimental (13)C KIEs fit qualitatively with the expected rate-limiting cyclic transition state, but they are far higher than theoretical predictions based on conventional transition state theory. This discrepancy is attributed to a substantial contribution of heavy-atom tunneling to the reaction, and this is supported by multidimensional tunneling calculations that reproduce the observed KIEs.

SUBMITTER: Vetticatt MJ 

PROVIDER: S-EPMC3345075 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature