Catalytic Asymmetric Synthesis Of P-stereogenic Compounds

P-stereogenic compounds are very important ligands in asymmetric reactions. Traditionally, the synthesis of these phosphorus compounds involves the optical resolution of racemates or starts from chiral pools. The development of new synthetic methods through asymmetric catalysis is very important for the preparation of P-stereogenic compounds. My dissertation research focuses on the asymmetric reactions of methyl phenyl phosphine with electron-deficient alkenes and alkyl halides, which will produce the corresponding P-stereogenic phosphorus compounds. It includes two parts as shown below.1. Asymmetric1,4-addition of phenylmethylphosphine to electron-deficient alkenes catalyzed by chiral NCN Pincer-Pd catalysts.Asymmetric addition reactions of phenylmethylphosphine to various enones and a,(3-unsaturated N-acylpyroles were investigated. The corresponding1,4-adducts having both P-and C-stereogenic centers were produced with good yields (86-98%) and excellent enantioselectivities (81-97%) by the use of new NCN Pincer-Pd catalysts in the presence of50mol%KOAc in toluene at-5℃.2. Asymmetric alkylation of phenylmethylphosphine with alkyl halides catalyzed by chiral PCP Pincer-Pd catalystAsymmetric alkylation of phenylmethylphosphine with various alkyl chlorides and bromides were investigated in the presence of PCP Pincer-Pd complex as the catalyst. Various P-stereogenic phosphorus compounds were produced with good yields (75-95%) in moderate enantioselectivies (24-56%).