Synthesis and characterization of enantiopure chiral NH 2 /SO palladium complexes.

A series of enantiopure chiral NH 2 /SO palladium complexes have been synthesised with high yields by treating the corresponding tert -butylsulfinamide/sulfoxide derivatives with Pd(CH 3 CN) 2 Cl 2 . The enantiopure chiral ligands were prepared by stereoselective addition of tert -butyl or phenyl methylsulfinyl carbanions to different tert -butylsulfinylimines. In all cases, coordination occurs with concomitant desulfinylation. X-ray studies of the Pd complexes showed a higher trans influence of the phenylsulfinyl group in comparison to that of the tert -butylsulfinyl group. Furthermore, we have obtained and characterised two possible palladium amine/sulfonyl complexes, epimers at sulfur, resulting from N -desulfinylation and coordination of palladium with both oxygens of the prochiral sulfonyl group. The catalytic activity and enantioselectivity of the new Pd(II) complexes of acetylated amine/ tert -butyl- and phenylsulfoxides in the carboxylated cyclopropanes arylation reaction has been studied, obtaining the best results with the phenylsulfoxide ligand 25(SC,SS) that produced the final arylated product in a 93 :7 enantiomeric ratio.