title: Asymmetric one-pot sequential organo- and gold catalysis for the enantioselective synthesis of dihydropyrrole derivatives.
abstract: A direct asymmetric one-pot synthesis of optically active 2,3-dihydropyrroles from propargylated malononitrile and N-Boc-protected (Boc = tert-butoxycarbonyl) imines is presented. The approach is based on a bifunctional organocatalytic Mannich-type reaction and a subsequent gold-catalyzed alkyne hydroamination and isomerization. The compatibility of both catalytic systems is presented and the overall transformation results in good yields (up to 70 %) with high selectivities (endo/exo > 10:1) and enantioselectivities (up to 88 % ee). The absolute configuration of the final products is unambiguously established by X-ray analysis. To highlight the synthetic potential of the accessed heterocyclic compounds, their transformation into 1-pyrrolines, which represent direct precursors of pyrrolidines, is presented.
authors.affiliation: Center for Catalysis, Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark.
authors.forename: David
authors.initials: D
authors.lastname: Monge
authors.forename: Kim L
authors.initials: KL
authors.lastname: Jensen
authors.forename: Patrick T
authors.initials: PT
authors.lastname: Franke
authors.forename: Lennart
authors.initials: L
authors.lastname: Lykke
authors.forename: Karl Anker
authors.initials: KA
authors.lastname: Jørgensen