The first helicene structure was reported by
Jakob Meisenheimer in 1903 as the reduction product of
2-nitronaphthalene. In one study, [5]helicene was synthesized in an
olefin metathesis reaction of a divinyl compound (prepared from
1,1′-bi-2-naphthol (BINOL) in several steps), with
Grubbs' second generation catalyst: Other approach is also non-photochemical and is based on assembly of biphenylyl-naphthalenes and their platinum-catalyzed double cycloisomerization leading to various [6]helicenes: : File:Tetrahelicene.jpg|[4]Helicene File:Pentahelicene.jpg|[5]Helicene File:Hexahelicene2.jpg|[6]Helicene File:Hexahelicene.jpg|[6]Helicene, minus
chirality File:Heptahelicene2.jpg|[7]Helicene File:Heptahelicene.jpg|[7]Helicene, minus chirality File:Octahelicene.jpg|[8]Helicene File:Nonahelicene.jpg|[9]Helicene File:Decahelicene.jpg|[10]Helicene File:Undecahelicene.jpg|[11]Helicene File:Dodecahelicene.jpg|[12]Helicene File:Tridecahelicene.jpg|[13]Helicene File:Tetradecahelicene.jpg|[14]Helicene File:Pentadecahelicene.jpg|[15]Helicene File:Hexadecahelicene.jpg|[16]Helicene File:Octadecahelicene.jpg|[18]Helicene == Applications ==