Studies On The Catalytic Asymmetric Methylation And Arylation Of Aldehydes

In this thesis, the asymmetric methylation and arylation of aldehydes were investigated in the presence of catalytic amount of novel chiral aziridino alcohol ligands bearing two stereogenic centers.1. The application of chiral aziridino alcohol ligands in the catalytic asymmetric addition of dimethylzinc to aldehydes.In the presence of the chiral aziridino alcohol ligand 1 as catalyst, the asymmetric methylation addition of dimethylzinc with aldehydes to afford the corresponding products in up to 91.9% yield with 97.0% enantiomeric excess.With the chiral aziridino alcohol ligand 2 as catalyst, the asymmetric methylation addition of dimethylzinc with aldehydes afforded the corresponding products in up to 94.6% yield with 96.2% enantiomeric excess. And the result show that two different enantiomers were obtained when ligand 1 and 2 were used as catalyst respectively.2. The application of chiral aziridino alcohol ligands in the catalytic asymmetric arylation of arylaldehydes. Asymmetric aryl transfer reactions of arylaldehydes were catalyzed by chiral ligand 1 and 2. In the presence of a catalytic amount(20mol%) of the ligand 1(2), the enantio-selective arylation of aldehydes afforded addition products in up to 93.7% yield with up to 98.2% enantionmeric excess. At the same time, with the same ligand as catalyst, both enantiomers of the products were obtained by choosing the appropriate arylboronic acid and arylaldehyde as ary donor and acceptor respectively.