|A recent contribution from the Kendall Houk laboratory concerns the asymmtric version of a palladium catalysed beta C-H-activation (Gang Chen et al. DOI). This work builds on work done by Giri et al. in 2005 on asymmetric Pd iodination (DOI). |
The substrates are amides with unactivated protons at the beta position. The large fluorinated aryl group acts as a directing group. The catalyst system is palladium acetate and a custom-built bulky chiral aminoethyl quinoline ligand (isoquinoline plus N-Sulfinyl imine chemistry). In the transition state palladium is coordinated to all three nitrogen atoms with remaining coordination site interacting with the beta methylene group. Yield 78%, enantiomeric ratio 95:5.