874758-26-6Relevant articles and documents
Ortho effect in the Bergman cyclization: Interception of p-benzyne intermediate by intramolecular hydrogen abstraction
Zeidan, Tarek A.,Manoharan, Mariappan,Alabugin, Igor V.
, p. 954 - 961 (2006)
Intramolecular hydrogen atom (H-atom) abstraction from the o-OCH 3 group effectively intercepts the p-benzyne intermediate in the Bergman cycloaromatization of 2,3-diethynyl-1-methoxybenzene (1) before this intermediate undergoes either retro-Bergman ring opening or external H-atom abstraction. This process leads to the formation of a new diradical and renders the cyclization step essentially irreversible. Chemical and kinetic consequences of this phenomenon were investigated through the combination of computational and experimental studies.