76670-39-8Relevant articles and documents
Convenient Phenacene Synthesis by Sequentially Performed Wittig Reaction and Mallory Photocyclization Using Continuous-Flow Techniques
Okamoto, Hideki,Takahashi, Haruhiko,Takane, Takamitsu,Nishiyama, Yasuhiro,Kakiuchi, Kiyomi,Gohda, Shin,Yamaji, Minoru
, p. 2949 - 2957 (2017/06/27)
Various phenacenes possessing chrysene, picene, and fulminene frameworks were prepared by using a continuous-flow synthetic protocol in which Wittig reaction affording diarylethenes and their Mallory photocyclization producing phenacene skeletons were sequentially performed. The Wittig reaction solution, containing the diaryl ethene obtained from an arylaldehyde and an arylmethyltriphenylphosphonium salt, was mixed with an iodine solution in the flow system and, subsequently, the solution was subjected to the photoreaction. Desired phenacenes were obtained with high to moderate chemical yield. For the present protocol, isolation of the intermediary diarylethene, which is the key precursor of the phenacene, is unnecessary. The approach provides a convenient method to supply a variety of phenacene samples, which are needed for initial systematic surveys in material science.
An investigation of the scope of the 1,7-electrocyclization of α,β:γ,δ-conjugated azomethine ylides
Zhang, Weimin,Ning, Fuqiang,Váradi, Linda,Hibbs, David E.,Platts, James A.,Nyerges, Miklós,Anderson, Rosaleen J.,Groundwater, Paul W.
supporting information, p. 3621 - 3629 (2014/05/20)
Substituents on the diene component have little influence on the periselectivity of the cyclizations of α,β:γ,δ-conjugated azomethine ylides, with 1,7-electrocyclizations predominating. In some cases, subtle changes to these substituents can, however, influence the product formed, through their effect on the relative energies of the transition states for the 1,5- (6π) and 1,7-electrocyclization (8π) processes. The most striking changes in periselectivity occur for phenylethenyl-substituted azomethine ylides 3d-f, which can give either a pyrroline 4d,f or dihydrobenzazepine 6e, depending upon the alkene configuration.
