341970-20-5Relevant academic research and scientific papers
Effect of water molecules on the cycloaromatization of non-conjugated aromatic tetraynes
Kawano, Tomikazu,Inai, Hiroki,Miyawaki, Kazuhiro,Ueda, Ikuo
, p. 944 - 949 (2007/10/03)
Cycloaromatization of the thienyl tetrayne 1, which was prepared in several steps from bis(trimethylsilyl)butadiyne and 3-bromothiophene-2-carbaldehyde, in benzene (0.33 mM) in the presence of molecular sieves 3A at room temperature gave the indeno[2,1-b]thiophene ring-fused 1H-2-benzopyran derivative 10 and indeno[2,1-b]thiophene derivative 11 in 11 and 40% yields, respectively. In contrast, cycloaromatization of 1 in the presence of water molecules at room temperature gave the indeno[2,1-b]thiophene ring-fused 1H-2-benzopyran derivative 10 and the indene ring-fused indeno[2,1-b]thiophene derivative 12 in 82 and 14% yields, respectively. Cycloaromatization of the phenyl tetrayne 9 in the presence of water molecules at room temperature also resulted in a dramatic change in product yields.
Synthesis of indeno[1,2-b]phenanthrene-type heterocycles by cycloaromatization of acyclic non-conjugated benzotetraynes
Miyawaki, Kazuhiro,Ueno, Fukuko,Ueda, Ikuo
, p. 887 - 900 (2007/10/03)
A novel and simple procedure for the preparation of 6-oxa-, 6-thia-, and 6-azaindeno[1,2-b]phenanthrenes (4) by thermal cycloaromatization of acyclic non-conjugated benzotetraynes (3) is described.
Cycloaromatization of a non-conjugated polyenyne system: Synthesis of 5H-benzo[d]fluoreno[3,2-b]pyrans via diradicals generated from 1-[2-{4-(2-alkoxymethylphenyl)butan-1,3-dinyl}]phenylpentan-2,4-diyn -1-ols and trapping evidence for the 1,2-didehydrobenzene diradical
Miyawaki, Kazuhiro,Suzuki, Riho,Kawano, Tomikazu,Ueda, Ikuo
, p. 3943 - 3946 (2007/10/03)
Non-conjugated tetraynes 1 undergo thermal intramolecular cyclization to non-benzenoid diradicals (23) followed by radical cycloaromatization at 25°C to provide 7-dehydro-5H-benzo[d]fluoreno[3,2-b]pyran monoradical (24) and alkyl radicals (25). Hydrogen abstraction of 24 gives 5H-benzo[d]fluoreno[3,2-b]pyrans (3) which are converted to 4 by reaction with 25. On the other hand, 2 gives 5H-fluorenol (5), indicating the formation of 1,2-didehydrobenzene diradical intermediates (28 and 29). These radicals are trapped as the corresponding Diels-Alder-type products by reaction with an aromatic diene, anthracene.
