title: Catalytic generation of vinylthionium ions. (4 + 3)-Cycloadditions and Friedel-Crafts alkylations.
abstract: A 3-phenylsulfanyl-substituted allylic alcohol and an ester thereof were treated with Brønsted acids or a gold catalyst, respectively, to generate vinylthionium ions. These species react with dienes, primarily substituted furans, to give products of either (4 + 3)-cycloaddition or Friedel-Crafts alkylation. The results are rationalized on the basis of a stepwise mechanism in which the relative rates of ring closure versus proton loss in the intermediate σ-complex determine the course of the reaction.
authors.affiliation: Department of Chemistry, University of Missouri-Columbia , Columbia, Missouri 65211, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Topinka
authors.forename: Rama Rao
authors.initials: RR
authors.lastname: Tata
authors.forename: Michael
authors.initials: M
authors.lastname: Harmata