title: Synthesis of α-Methylene-β-Lactams via PPh3-Catalyzed Umpolung Cyclization of Propiolamides.
abstract: We report herein a facile synthesis of α-methylene-β-lactams. Thus, under the catalysis of triphenylphosphine, a number of 2-propiolamidoacetates or α-propiolamido ketones in refluxing ethanol underwent umpolung cyclization to afford the corresponding 4-substituted 3-methyleneazetidin-2-ones in high yields.
authors.affiliation: †Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhu
authors.affiliation: ‡Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: †Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.|‡Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China.
authors.forename: Chaozhong
authors.initials: C
authors.lastname: Li
mesh_terms: D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D003521:Cyclopropanes / Q000737:chemistry*; D007769:Lactams / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010720:Phosphines / Q000737:chemistry*
chemical_list: D000577:Amides; D003521:Cyclopropanes; D007769:Lactams; D010720:Phosphines