Diastereospecific dimerisation in bridging amido complexes of dipalladium

Chirality is conserved in the deprotonation of the complex PdCl2(L-a) (L-a = 2-[N-p-tolylamino)-methyl]pyridine; 1a) leading to the folded diastereomer of [PdCl(mu-L-a-H)](2) (2a), where the p-tolyl groups are syn exo and the same enantiomer of 1a shapes both halves of the amido-bridged dimer. The dimerization, of different enantiomers of 1a (R with S), which should lead to the achiral unfolded diastereomer of 2a where p-tolyl groups would arrange anti, is not observed.