Synthesis of 7-azabicyclo[2.2.1]heptane-1-carboxylate via silver/ThioClickFerrophos-catalyzed asymmetric 1,3-dipolar cycloaddition of dihydropyrrole ester with N-substituted maleimide

The AgOAc/ThioClickFerrophos-complex catalyzed the 1,3-dipolar cycloaddition of 3,4-dihydropyrrole-2-carboxylates, a precursor of cyclic azomethine ylides, with N-substituted maleimide to give the exo-cycloadducts, that is, 7-azabicyclo[2.2.1]heptane-1-carboxylates, as the major product in moderate yields with a high enantiomeric excess (up to 86% ee) under the optimized conditions. Michael adducts were produced as a minor product.