Synthesis And Application Of Novel Axially Chiral NHC-Pd(Ⅱ) And NHC-Rh(Ⅲ) Complexes Derived From BINAM And H₈-BINAM

This thesis mainly focused on the synthesis of axially chiral NHC-Rh(â…¢) and NHC-Pd(â…¡) complexes derived from BINAM and Hg-BINAM and applications of these complexes in the catalytic reactions. 1. An Efficient Asymmetric 1,4-Addition of Arylboronic Acids to 2,3-Dihydro-4-pyridones Catalyzed by Axially Chiral NHC-Pd (â…¡) Complexes.Novel axially chiral cis-chelated bidentate bis(N-heterocyclic carbene)-palladium(â…¡) complexesâ… -10 andâ… -11 derived from Hg-BINAM have been synthesized. Their structures have been characterized by X-ray diffraction of single crystals. Axially chiral NHC-Pd(â…¡) complexesâ… -2,â… -3 andâ… -4 are effective catalysts for the asymmetric conjugate addition of arylboronic acids to 2,3-dihydro-4-pyridones, producing the synthetically and biologically important 2-aryl-4-piperidones in moderate to high yields (up to 96%) and with excellent enantioselectivities (up to> 99.5%ee), in most cases under mild conditions. However, bis(NHC)-Pd(â…¡) complexesâ… -1,â… -10 andâ… -11 were ineffective in this reaction. 2. Synthesis of Novel Axially Chiral NHC-Rh(â…¢) Complexes Derived from BINAM and Hg-BINAM and Application in the Enantioselective Hydrosilylation of 3-Oxo-3-arylpropionic Acid Methyl or Ethyl Esters.Novel axially chiral cis-chelated bidentate bis(N-heterocyclic carbene)-Rhodium (â…¢) complexesâ…¡-2 derived from Hg-BINAM have been synthesized. Their structures have been characterized by X-ray diffraction of single crystals. Axially chiral N-heterocyclic carbene (NHC)-Rh(â…¢) complexesâ…¡-11 andâ…¡-2 were applied in the enantioselective hydrosilylation of 3-oxo-3-arylpropionic acid methyl or ethyl esters. The reduction products, 3-hydroxy-3-arylpropionic acid methyl or ethyl esters, could be obtained in good yields (up to 90%) with good to excellent enantioselectivities (up to 99%ee) under mild conditions. 3. A Novel cis-Chelated Pd(â…¡)-NHC Complex for Catalyzing Suzuki and Heck-type Cross-coupling Reactions.Axially chiral cis-chelated bidentate bis(N-heterocyclic carbene)-palladium(â…¡) complexâ… -1 is fairly effective in Suzuki cross-coupling reaction. Using either aryl bromides or iodobenzene as substrates afforded coupling products in 75-99%yields, moreover, using aryl chlorides afforded moderate yields of the coupling products. Complexâ… -1 was also effective in Heck-type cross-coupling reaction to give the corresponding products in good to excellent yields (up to 99%) in most cases.