Cyclooligomerisation of quinones

DFT and QTAIM study of the tetra-tert-butyltetraoxa[8]circulene regioisomers structure

“…The symmetric tetraoxa [8]circulenes [1][2][3][4][5][6][7] attract the research interest as a promising electroluminescent material for organic light-emitting diodes (OLEDs) [8][9][10][11]. The first reliable structure description of the simplest symmetric tetraoxa [8]circulene (Fig.…”

Organic Light‐Emitting Diodes from Symmetrical and Unsymmetrical π‐Extended Tetraoxa[8]circulenes

“…[7] The structure of the tetraoxa[8]-circulene framework was deduced by means of mass spectrometry of the all-naphthalene tetraoxa [8]circulene (4 N) by Erdtman and Hçgberg, and was later confirmed by single-crystal X-ray crystallography. [8][9][10][11] It became clear that when one side of the 1,4-benzoquinone was substituted, either by using 1,4-naphthoquinone or a 2,3-disubstituted-1,4-benzoquinone, the tetraoxa [8]circulene was a major product upon acid treatment. More recently a series of liquid-crystalline tetraoxa [8]circulenes were synthesised by attachment of linear alkyl chains to the tetraoxa [8]circulene framework.…”

Synthesis of tetraphenylene derivatives and their recent advances

“…In 1970, Erdtman and Högber established a method for tetrameric condensation of quinones, in which tetraoxa [8]circulene (101) (R = H) was formed in the presence of a strong acid [65]. Recently, Christensen and co-workers reported oligomerization of 2,3-disubstituted-1,4-benzoquinones substituted with hydrophobic long chains to generate various tetraoxa [8]circulenes containing alkyl groups (101) (Scheme 35; Equation 1) [66].…”