Design, Synthesis Of Chiral Diphenylprolinol-derived PCP-Pincer PD(Ⅱ) Complexes And Their Applications In Asymmetric Catalysis

With this context, chiral PCP-Pincer Pd(â…¡) complexes with L-proline chiral auxiliaries have been synthesized by a "four-component, one-pot phosphorylatio-n/palladation" procedure via C-H bond activation of the related ligands. Moreover, we examined their catalytic activities and stereoselectivities in the related asymmetric reactions.This dissertation mainly focuses on 2 aspects as follows:(1) The optically pure PCP-pincer palladium complex 9 and 10 were easily prepared by a "four-component, one-pot phosphorylation/palladation" procedure via C-H bond activation of the related ligands. Additionally, complex 11 could be obtained by the halogen exchange reaction of chloride complex 9 with excess amounts KI, or by the oxidative addition route using 2-iodoresorcinol as a backbone. All the chiral PCP-Pincer Pd(â…¡) complexes were characterized by elemental analysis,1H NMR,13C NMR,31P NMR. The X-ray structure analysis of each complex established the stereochemical configuration at the phrosphous atom. (2) The asymmetric alkylation of aldehyde or sulfonimine with allyltributyltin was used as a model reaction to examine the catalytic efficiencies of these chiral PCP-pincer Pd(â…¡) complexes. The preliminary investigation indicated that the more bulky complex 2 gave better results in allylation of 4-nitrobenzenesulfonimine, affording the produet in a good yield (77%) with moterate enantioselectity (69% ee).