Versatile halogenation via a C NHC ^C sp3 palladacycle intermediate.

Stable cyclopalladated complexes containing an (sp 3 )C-Pd bond were synthesized via α-CH 2 deprotonation and palladation of N -alkyl groups of carbene ligands bearing electron-withdrawing substituents. The strong electron donating strengths of the resulting C NHC ^C sp3 chelators were experimentally identified, and the palladacycle underwent template-directed, versatile C-halogenation with X 2 .