Asymmetric Diels-Alder Reaction Catalyzed by a Chiral Diammonium Salt

Significance

A new organocatalytic asymmetric Diels-Alder reaction has been reported. The diammonium salt of chiral 1,1′-binaphthyl-2,2′-diamine and Tf₂NH catalyzes the reaction of dienes 1 with α-acyloxyacroleins 2 to give adducts of type 3 in good yields, enantioselectivities and diastereoselectivities. Both cyclic as well as acyclic precursors 1 can be used. In addition, a transition state, based on NMR spectroscopy and X-ray crystal structure analysis, to explain the observed relative and absolute configuration is proposed.