title: Use of a new spirophosphine to achieve catalytic enantioselective [4 + 1] annulations of amines with allenes to generate dihydropyrroles.
abstract: Due in part to the common occurrence of five-membered nitrogen heterocycles in bioactive molecules, the discovery of methods for the enantioselective synthesis of such structures is a useful endeavor. Building on a single example by Tong of a phosphine-catalyzed [4 + 1] annulation of an amine with an allene that furnished an achiral dihydropyrrole in 22% yield, we have developed, with the aid of a new chiral spirophosphine catalyst, a method with increased utility, specifically, improved yield, enhanced scope (the use of γ-substituted allenes), and good ee. The enantioenriched dihydropyrrole products can be transformed into other interesting families of compounds with very good stereoselectivity.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
authors.forename: Søren
authors.initials: S
authors.lastname: Kramer
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Fu
mesh_terms: D000466:Alkadienes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D010720:Phosphines / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis*
chemical_list: D000466:Alkadienes; D000588:Amines; D010720:Phosphines; D011758:Pyrroles; C025947:propadiene