Stereochemical investigation of a kinetically labile chiral organopalladium complex in solution

Abstract

According to the relative locations of the R and S stereogenic centres in the diamine chelate, the kinetically labile complex (+)-[Pd{(S)- CH3CH(1-C10H6)NMe2-C 2,N}{(R,S)-Me2NCH(Me)CH(Me)NMe 2-N,N′}]ClO4 exists as an equilibrium mixture of two stereochemically distinct isomers in solution. The equilibrium ratio is temperature and solvent dependent. In d2-dichloromethane, the minor isomer observed at room temperature diminishes when the temperature is lowered to -20°C. A low temperature 2-D ROESY NMR experiment is used to identify the sterically favored major isomer in solution and hence to evaluate the efficiency of the chiral inductive effects of coordinated (S)-dimethyl(1-(α-naphthyl)ethyl)amine.