Synthesis of the novel fused pi-electronic systems by the intramolecular electrophilic attack of tropylium ion

通过鎓离子分子内亲电攻击合成新型熔融π电子系统

• 批准号: 08640685
• 负责人: YAMAMURA Kimiaki
• 金额: $ 0.32万
• 依托单位: KOBE UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08640685/
• 关键词: tropylium ion; benzazulene; azulenothiophene; pi-conjugated system; triphenylene; alpha, beta-unsaturated ketone; azulene; furan; π-共役系; α,β-不飽和ケトン; ベンズ〔a〕アズレン; フラン環の解裂; 縮環π電子系化合物; ベンズ〔g〕クリセン; α、β-不飽和カルボニル化合物; 縮合ヘテロ芳香族化合物; 縮環π電子系カチオン

Fused full pi-conjugated systemss containing seven-membered ring are molecules of both theoretical and experimental interest due to their unique electronic structures, and various kinds of such compounds have been prepared. However the reported synthetic methods generally suffered from tedious multistep procedures and low yields at the stage of construction of the unsaturated seven-membered ring. We pay our attention to electrophilic nature of tropylium ion, and developed two facile synthetic methods of the compounds containing conjugated seven-membered ring. Our synthetic stratery was to use commercially available 1,3,5-cycloheptatriene as the seven-membered unit.1) The facile and novel synthesis of fused full conjugated cyclic compounds containing tropylium ion by an intramolecular Friedel-Crafts type reaction of o-aryl-, and o-heteroaryl-tropyliobenzenes. Cyclohepta [a] thienonaphthalenylium ions and cyclohepta [a] furonaphthalenylium ion which are the isoelectronic cations of triphenylene, and cyclohepta [a] benzofuro [c] naphthalenylium ions, cyclohepta [alpha] benzothieno [c] naphthalenylium ions and cyclohepta [a] indoro [c] naphthalenylium ion which are the isoelectronic carbocations of the potent carcinogenic benzo [g] chrysene, were obtained in reasonable yields.2) The facile and novel synthesis of heteroaromatic fused azurene derivatives.beta- (10-Benz [a] -azulenyl) -a, b-unsaturated ketone and beta- (9-azuleno [1,2-b] thienyl) -alpha, beta-unsaturated ketones were obtained from omicron- [2-furyl] tropyliobenzenes and 1-tropylio-2- [2-furyl] thiophenes, respectively, in reasonable yields. The mechanism involving a novel ring-cyclization by intramolecular attack of the tropylium ion to the 2-position of the furan ring is postulated. X-ray crystal structure of two of beta- (9-azuleno [1,2-b] thienyl) -alpha, beta-unsaturated ketones have been determined.

含有七元环的稠合全π共轭体系由于其独特的电子结构而成为具有理论和实验意义的分子，并且已经制备了各种此类化合物。然而，已报道的合成方法普遍存在繁琐的多步程序和在不饱和七元环构建阶段的低产率。我们关注托吡鎓离子的亲电性质，开发了两种含共轭七元环化合物的简便合成方法。我们的合成策略是使用市售的1,3,5-环庚三烯作为七元单元。 1）通过邻芳基的分子内Friedel-Crafts型反应，简便而新颖地合成含托鎓离子的稠合全共轭环状化合物-，和邻杂芳基-热带苯。环庚[a]噻吩并萘离子和环庚[a]呋喃萘离子是苯并菲的等电子阳离子，以及环庚[a]苯并呋喃[c]萘离子、环庚[α]苯并噻吩[c]萘离子和环庚[a]吲哚[ c] 萘基离子，它们是以合理的产率获得了强致癌性苯并[g]屈的等电子碳正离子。2）杂芳族稠合天青衍生物的简便且新颖的合成。β-（10-Benz [a]-azulenyl）-a，b-不饱和酮和 β-(9-azuleno [1,2-b] 噻吩基)-α,β-不饱和酮是从 omicron- 获得的分别以合理的收率制备[2-呋喃基] 托吡基苯和1-托吡基-2-[2-呋喃基]噻吩。假设了涉及通过鎓离子分子内攻击呋喃环的 2-位而进行的新型环环化的机制。两种 β-（9-azuleno [1,2-b] 噻吩基）-α、β-不饱和酮的 X 射线晶体结构已确定。