| Catalytic asymmetric addition reactions of nucleophiles to carbonyl and imine electrophiles are important processes in asymmetric synthesis. Such addition reactions are intrinsically efficient in the production of a wide range of valuable enantiomerically pure compounds, as a new chiral center and a new carbon-carbon bond are established in a single operation. The quest for efficient catalytic systems and chiral ligands plays a crucial role in expanding the utility of this strategy. Furthermore, for the practical applications of useful catalytic asymmetric synthesis, it is highly desirable to develop convenient methods for the preparation of effective chiral ligands.; Over the past two decades, the catalytic asymmetric addition employed enolsilanes (aldol addition), allyl-stannanes (allylaytion), and dialkylzinc (alkylation) have proven remarkably effective and products with excellent enantiomeric excesses have been achieved for different types of C=X electrophiles. Compared to the above well-established reactions, however, the catalytic asymmetric alkenyl, aryl and alkynl transfer to carbonyl and imine compounds are substantially less developed in spite of their importance in organic synthesis. In this study, we have developed a convenient, one-step synthesis of optically active tertiary aminonaphthols, which were found to be very effective chiral ligands in the catalytic asymmetric phenyl and alkenyl transfer to aldehydes. An efficient methodology of Ag (I) and Cu (I)/(II)-catalyzed alkynlation of alpha-amino esters to synthesis beta, gamma-alkynyl alpha-amino acids derivatives has also been developed. |
