Thwarting beta-Hydride Elimination: Capture of the Alkylpalladium Intermediate of an Asymmetric Intramolecular Heck Reaction This research was supported by the National Institutes of Health (grant GM-12389). M.O. thanks the Deutsche Forschungsgemeinschaft (DFG) for an Emmy Noether fellowship (Oe 249/1-1). NMR and mass spectra were determined at the University of California, Irvine with instruments purchased with the assistance of the NSF and NIH shared instrumentation programs. We are grateful to Dr. Joseph W. Ziller and Dr. John Greaves for their assistance with X-ray structure and mass spectrometric analyses.