title: Lewis acid-promoted three-component reactions of propargylic alcohols with 2-butynedioates and secondary amines.
abstract: We report herein a three-component reaction of propargylic alcohols with 2-butynedioates and secondary amines, which furnished functionalized dihydroazepines. In the cases where benzylmethylamine and benzyl-i-propylamine were used as the secondary amine, the reaction afforded 2,5-dihydro-1H-pyrroles and 2,3-dihydro-1H-pyrroles, respectively, as the major product along with the desired dihydroazepines. The reaction mode depends on the electronic and steric effect of the substitutents on the secondary amines used. A tentative mechanism for this cascade process is postulated. The key intermediate is ascribed to 1,3,4-pentatrien-1-amine, which is formed by trapping the in situ generating allenic carbocation with enamine. Because of the reactivity of 1,3,4-pentatrien-1-amine formed, different products were thus formed.
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Guangwei
authors.initials: G
authors.lastname: Yin
authors.forename: Yuanxun
authors.initials: Y
authors.lastname: Zhu
authors.forename: Ping
authors.initials: P
authors.lastname: Lu
authors.forename: Yanguang
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D002087:Butyrates / Q000737:chemistry*; D058116:Lewis Acids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D020005:Propanols / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry
chemical_list: D000480:Alkynes; D000588:Amines; D002087:Butyrates; D058116:Lewis Acids; D020005:Propanols; D011758:Pyrroles; C028255:propargyl alcohol