title: Synthesis and mechanistic study of fused 2-pyrrolines via thermolysis of 6-substituted-3,5-hexadienyl azidoformates.
abstract: Thermolysis of 3,5-hexadienyl azidoformates at 300 degrees C, 0.05 Torr, led to a fused 2-pyrroline regiospecifically, regardless of the configuration E or Z between the C-3 and C-4 double bond. Thermolysis of 6-substituted-3,5(E)-hexadienyl azidoformates yielded a kinetically controlled 2-pyrroline with cis configuration between H-1 and H-8a whereas 6-substituted-3,5(Z)-hexadienyl azidoformates produced a cis and trans mixture. The mechanism was proposed as the loss of nitrogen to form an acyl nitrene, then addition to a double bond to produce an aziridine. Finally the cleavage of the C-C bond generated a vinylazomethine ylide followed by recyclization to a fused 2-pyrroline.
authors.affiliation: Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 701, Republic of China. wupl@mail.ncku.edu.tw
authors.forename: P L
authors.initials: PL
authors.lastname: Wu
authors.forename: T H
authors.initials: TH
authors.lastname: Chung
authors.forename: Y
authors.initials: Y
authors.lastname: Chou