title: Biradical and zwitterionic cyclizations of oxy-substituted enyne-allenes.
abstract: [see reaction]. Oxyanion substitution of enyne-allenes causes both Myers-Saito and Schmittel cyclizations to switch their product formation preferences from diradicals to polar, closed-shell singlets. The oxyanion stabilization is larger for the Schmittel products than the Myers-Saito products because the latter must sacrifice aromaticity to maximize interaction. The changing character of the different reaction paths is reflected in their activation energies.
authors.affiliation: Department of Chemistry and Supercomputer Institute, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455-0431, USA. cramer@dchem.umn.edu
authors.forename: C J
authors.initials: CJ
authors.lastname: Cramer
authors.forename: B L
authors.initials: BL
authors.lastname: Kormos
authors.forename: M
authors.initials: M
authors.lastname: Seierstad
authors.forename: E C
authors.initials: EC
authors.lastname: Sherer
authors.forename: P
authors.initials: P
authors.lastname: Winget