Organocatalytic Enantioselective Diels−Alder Reaction of Dienes with α-(<i>N</i>,<i>N</i>-Diacylamino)acroleins

Catalytic and highly enantioselective Diels−Alder reaction of cyclic and acyclic dienes with α-phthalimidoacroleins provides cyclic α-quaternary α-amino acid precursors. The conformationally flexible chiral ammonium salt of H-l-Phe-l-Leu-N(CH2CH2)2-reduced triamine with pentafluorobenzensulfonic acid is very effective as an asymmetric catalyst for the Diels−Alder reaction.