Reactions of Phenyltriazolinedione with Alkenes. Stereochemistry of Methanol Adducts to Aziridinium Imide Intermediates
作者:Ioulia Smonou、Saeed Khan、Christopher S. Foote、Yiannis Elemes、Irene M. Mavridis、Ariadne Pantidou、Michael Orfanopoulos
DOI:10.1021/ja00132a006
日期:1995.7
The addition of 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) and the stereochemistry of methanol/PTAD adduct formation with cis- and trans-2-butenes, 1-methylcyclopentene, (E)-2-methyl-2-butene-1,1,1-d(3), and substituted indenes (indene, 2-methylindene, 2,3-dimethylindene) have been investigated. There is no loss of stereochemistry in the addition of MeOH and PTAD to butenes, 1-methylcyclopentene, 2-methyl-2-butene, and indene. However, in methyl-substituted indenes 9 and 14, loss of stereochemistry at the reaction center is observed. An aziridinium imide (AI) is proposed as an intermediate in all these systems. The stability of the AI intermediate and its equilibration with an open zwitterion depend on the particular system. Only in the benzylically-stabilized tertiary indenes is the open zwitterion stable enough to cause loss of stereochemistry.