title: Alkaloid-Catalyzed Enantioselective [3 + 2] Cycloaddition of Ketenes and Azomethine Imines.
abstract: A new asymmetric synthesis of bicyclic pyrazolidinones through an alkaloid-catalyzed formal [3 + 2] cycloaddition of in situ generated ketenes and azomethine imines is described. The products were formed in good to excellent yields (52-99% for 17 examples), with good to excellent diastereoselectivity (dr 5:1 to 27:1 for 11 examples), and with excellent enantioselectivity in all cases (≥96% ee). This method represents the first unambiguous example of an enantioselective reaction between ketenes and a 1,3-dipole.
authors: Department of Chemistry, Oakland University , 2200 North Squirrel Road, Rochester, Michigan 48309-4477, United States.
authors: Mukulesh
authors: M
authors: Mondal
authors: Department of Chemistry, Eastern Illinois University , 600 Lincoln Avenue, Charleston, Illinois 61920-3099, United States.
authors: Kraig A
authors: KA
authors: Wheeler
authors: Department of Chemistry, Oakland University , 2200 North Squirrel Road, Rochester, Michigan 48309-4477, United States.
authors: Nessan J
authors: NJ
authors: Kerrigan
mesh_terms: D000470:Alkaloids / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D061565:Cycloaddition Reaction; D005030:Ethylenes / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013882:Thiosemicarbazones / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D001391:Azo Compounds; D005030:Ethylenes; D007097:Imines; D007659:Ketones; D011720:Pyrazoles; D013882:Thiosemicarbazones; C512188:azomethine; C008223:ketene