Synthesis, structure, and catalytic activity of palladium complexes with new chiral cyclohexane-1,2-based di-NHC-ligands

A pair of novel palladium complexes {[(1S,2S)-L]PdBr2} and {[(1R,2R)-L]PdBr2} of chiral di-N-heterocyclic carbene ligands derived from chiral 1,2-cyclohexanediamine have been prepared in moderate to good yields and characterized by NMR, HRMS and X-ray single crystal diffraction studies. The obtained chiral NHC–Pd compound was able to catalyze the asymmetric Suzuki–Miyaura couplings of aryl bromides with arylboronic acids in good yields and moderate enantioselectivities (up to 61% ee).