Absolute configuration, coordination and stereochemical influence of 1,3,5,7-tetramethyl-2,6,9-trioxo-bicyclo[3,3,1]nona-3,7-diene in Rh(I) and cationic Pd(II) complexes

Relevant stereochemical and coordination features of 1,3,5,7-tetramethyl-2,6,9-trioxo-bicyclo[3,3,1]nona-3,7-diene (TOND), a chiral molecule of C2 symmetry are described. The X-ray crystal structure of [RhCl{(S)-CHPhMeNH2}{(+)-TOND}] has ascertained that the absolute configuration of (+)-TOND is R,R. Furthermore, the synthesis of stable cationic Pd(II) π-allyl complexes of general formula [Pd(η3-allyl)(TOND)][BF4] has allowed to probe the ability of this ligand to afford stereoselective coordination of prochiral fragments. The X-ray molecular structure of the representative compound [Pd(η3-crotyl)(TOND)][BF4] has been determined. Finally, the influence of TOND on the stereochemistry of prochiral nitrogen donors of diamine and phosphamine chelates has been explored in rhodium complexes of general formula [Rh(chelate)(TOND)][BF4]. The configurations of the nitrogen donors have resulted as stereospecifically selected by the presence of TOND.