An enantioselective Diels-Alder reaction of 1,2-dihydropyridines with α-acyloxyacroleins catalyzed by a chiral primary ammonium salt.

ABSTRACT

The first enantioselective Diels-Alder reaction of 1,2-dihydropyridines with α-acyloxyacroleins catalyzed by a chiral primary ammonium salt has been developed and it offers more efficient routes to key synthetic intermediates of alkaloids, for which the direct preparations were unavailable before. The asymmetric induction can be understood through the optimized geometry of an iminium salt aqua complex derived from the catalyst and the dienophile.