title: The use of cobalt-mediated cycloisomerisation of ynedinitriles in the synthesis of pyridazinohelicenes.
abstract: A cobalt-mediated [2+2+2] cycloisomerisation of ynedinitriles to helical pyridazines in good to high yields was developed. The construction of the pyridazine nucleus from one alkyne and two nitrile units is proposed to follow either a conventional organometallic mechanism or to be triggered by a single-electron transfer from a Co(II) species. Various [5]-, [6]- and [7]helicene pyridazines were prepared.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Prague 6 (Czech Republic).
authors.forename: Serghei
authors.initials: S
authors.lastname: Chercheja
authors.forename: Jiří
authors.initials: J
authors.lastname: Klívar
authors.forename: Andrej
authors.initials: A
authors.lastname: Jančařík
authors.forename: Jiří
authors.initials: J
authors.lastname: Rybáček
authors.forename: Simon
authors.initials: S
authors.lastname: Salzl
authors.forename: Ján
authors.initials: J
authors.lastname: Tarábek
authors.forename: Lubomír
authors.initials: L
authors.lastname: Pospíšil
authors.forename: Jana
authors.initials: J
authors.lastname: Vacek Chocholoušová
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Vacek
authors.forename: Radek
authors.initials: R
authors.lastname: Pohl
authors.forename: Ivana
authors.initials: I
authors.lastname: Císařová
authors.forename: Ivo
authors.initials: I
authors.lastname: Starý
authors.forename: Irena G
authors.initials: IG
authors.lastname: Stará
keywords: cobalt; cyclization; helical structures; heterocycles; radicals