The challenging control of the absolute configuration of chiral-at-metal Complexes is efficiently achieved using the tripodal tetradentate ligand L. The optical resolution of rac-[RhCl2(kappa C-4,N,N',P-L)] mediated by (S)-alpha-phenylslycirie provides access to enantiopure complexes- of general formula [Rh(kappa C-4,N,N',P-L)A-(Solv)][SbF6](n) that enantioselectively catalyze the Diels-Alder reaction between methacrolein and HCp with enantiomeric ratio of up to >99/1. The nature of the active species, the origin of the enantioselectivity and mechanistic details are disclosed by means of NMR spectroscopy and DFT studies.