Investigation of Lewis Acid-Catalyzed Asymmetric Aza-Diels−Alder Reactions of 2H-Azirines
journal contributionposted on 26.12.2003, 00:00 by Åsa Sjöholm Timén, Peter Somfai
Asymmetric Diels−Alder reactions with 2H-azirines as dienophiles have been studied. Diastereoselective reactions with an enantiopure azirine 1b, bearing a chiral auxiliary, gave substituted bi- and tricyclic tetrahydropyridines in high yield and stereoselectivity, under the influence of a Lewis acid. The novel enantioselective [4+2] cycloaddition reaction of 3-benzyl-2H-azirine carboxylate with cyclopentadiene was investigated with various chiral Lewis acid complexes and provided the corresponding tetrahydropyridines in moderate to low yield and enantioselectivity.