Asymmetric Synthesis by Stereocontrol

Abstract

Diels-Alder cycloadditions of S-indoline chiral acrylamides with cyclopentadiene in the presence of Lewis acids proceed with high diastereofacial selectivity, giving either endo-R or endo-S products depending on Lewis acid and the structures of chiral dienophiles. Diastereo- and enantioselective pinacol coupling reactions of chiral alpha -ketoamides mediated by samarium diiodide afforded extremely high diastereoselectivities. Enantiopure (S,S)- or (R,R)-2,3-dialkyltartaric acid and derivatives can be synthesized. Furthermore, it was demonstrated that alpha,beta -unsaturated amides coupled with SmI2 to dimerized products containing two chiral carbons which were first obtained as the adjacent chiral carbons.