title: The thermal C2-C6/[2 + 2] cyclisation of enyne-allenes: reversible diradical formation.
abstract: New enyne-allenes, structurally designed toward the thermal C(2)-C(6)/[2 + 2] cyclisation mode, were prepared and characterised, one of them even by X-ray crystallography. The mechanism of their transformation to formal [2 + 2] cycloadducts was interrogated by trapping experiments and DFT computations. The results support a stepwise mechanism that involves the reversible formation of the C(2)-C(6) diradical intermediate.
authors.affiliation: Department of Chemistry and Biology, Universität Siegen, Siegen, Germany.
authors.forename: Mehmet Emin
authors.initials: ME
authors.lastname: Cinar
authors.forename: Chandrasekhar
authors.initials: C
authors.lastname: Vavilala
authors.forename: Jian
authors.initials: J
authors.lastname: Fan
authors.forename: Michael
authors.initials: M
authors.lastname: Schmittel