摘要:
The addition reaction of chiral imines, (ent-10, 48, 70) and chiral enamino esters (52, 55, 73) with maleic anhydride (32), citraconic anhydride (57), alpha-chloroacrylonitrile (29), and nitroethylene (74), has been investigated. These condensations proved to be in general highly regio-, diastereo-, and enantioselective. In most cases the primary adducts underwent an in situ N-heterocyclization, allowing the enantioselective access to nitrogen-containing, five- and six-membered heterocycles.