title: Remote Pummerer Reaction via Intermolecular Through-Space Interaction between Sulfonium and Sulfenyl Sulfur Atoms.
abstract: The remote Pummerer reaction of the mono-sulfoxide of p-bis(methylthio)-aromatic 1 is described. The reaction of 1 with (CF(3)CO)(2)O in CH(2)Cl(2) gave a mixture of the corresponding mono-Pummerer product 2, the bis-Pummerer product 3, and the bis-sulfide 4 in an n:1:1 ratio (n >/= 2). The 1:1 formation of 3 and 4 indicates an intermolecular interaction between sulfur atoms. The reaction with the deuterium-labeled 1-d(3)() showed that the formation of 2 occurs at the sulfenyl as well as sulfinyl groups in 1a-d(3)()-1d-d(3)(), in which the product ratio of 2-d(3)():2-d(2)() is in the range of 3.5-10. On the other hand, the Pummerer reaction of 1e-d(3)() occurred preferably at the sulfinyl group in a usual manner. The reaction of a 1:1 mixture of the bis-sulfide 4 and the bis-sulfoxide 5 with (CF(3)CO)(2)O also gave 2, 3, and 4 in a ratio similar to that for the reaction of 1. The mechanism in the present remote Pummerer reactions is discussed in light of an intermolecular through-space interaction between the sulfonium and sulfenyl sulfur atoms, and a dithia dication dimer B and/or a bis(dithia dication) cyclic dimer C are proposed as intermediates.
authors.affiliation: Department of Chemistry and Tsukuba Advanced Research Alliance Center, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Emiko
authors.initials: E
authors.lastname: Koyama
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Namatame
authors.forename: Toyokazu
authors.initials: T
authors.lastname: Kitaura
authors.forename: Chihiro
authors.initials: C
authors.lastname: Kono
authors.forename: Mariko
authors.initials: M
authors.lastname: Goto
authors.forename: Takanobu
authors.initials: T
authors.lastname: Obinata
authors.forename: Naomichi
authors.initials: N
authors.lastname: Furukawa