Monomeric Cobalt Oxazoline Palladacycles (COP). Useful Catalysts for Catalytic Asymmetric Rearrangement of Allylic Trichloroacetimidates

Cobalt oxazoline palladacycles (COP) containing
acetylacetonate and hexafluoroacetylacetonate ligands were
prepared as catalysts for the asymmetric rearrangement of
allylic trichloroacetimidates. These monomeric catalysts are
more soluble than the previously described chloride-bridged
dimer COP-Cl (1). COP-hfacac (2) provides rearranged allylic
trichloroacetamides with high enantiomeric purities (91−98% ee) in solvents of widely varying polarities:  cyclohexane,
toluene, 1,2-dichloroethane, ethyl acetate, acetone, acetonitrile, and THF. The first single-crystal X-ray structure of a
COP catalyst is also reported.