Duality of Reactivity of a Biradicaloid Compound with an o-Quinodimethane Scaffold

Sahara, Keisuke; Abe, Manabu; Zipse, Hendrik und Kubo, Takashi (2020): Duality of Reactivity of a Biradicaloid Compound with an o-Quinodimethane Scaffold. In: Journal of the American Chemical Society, Bd. 142, Nr. 11: S. 5408-5418

Abstract

Sigmarene, which is a Kekule hydrocarbon with appreciable singlet biradical character originating from an o-quinodimethane scaffold, is isolated as a doubly sigma-bonded dimer. The dimer dissociates into a monomeric sigmarene upon heating or photoirradiation. The monomeric species undergoes a rapid [4 + 4] cycloaddition reaction under dark conditions even at room temperature to produce the dimer. Contrarily, the monomeric sigmarene undergoes a [4 + 2] cycloaddition reaction in the presence of dienophile as an orbital symmetry allowed process. Therefore, the sigmarene shows high reactivity for both symmetry-forbidden and allowed processes in the framework of the orbital symmetry rule. This duality of reactivity of the sigmarene is consistent with the intermediate singlet biradical character (44%) estimated by a density functional theory (DFT) calculation.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 0002-7863
• Sprache: Englisch