225519-95-9Relevant academic research and scientific papers
Remote Pummerer Reaction via Intermolecular Through-Space Interaction between Sulfonium and Sulfenyl Sulfur Atoms
Kobayashi, Kenji,Koyama, Emiko,Namatame, Kazuhiko,Kitaura, Toyokazu,Kono, Chihiro,Goto, Mariko,Obinata, Takanobu,Furukawa, Naomichi
, p. 3190 - 3195 (2007/10/03)
The remote Pummerer reaction of the mono-sulfoxide of p-bis(methylthio)-aromatic 1 is described. The reaction of 1 with (CF3CO)2O in CH2Cl2 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-d3 showed that the formation of 2 occurs at the sulfenyl as well as sulfinyl groups in 1a-d3-1d-d3, in which the product ratio of 2-d3:2-d2 is in the range of 3.5-10. On the other hand, the Pummerer reaction of 1e-d3 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 (CF3-CO)2O 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.
