通过将扭曲的烯烃激发态与用于双自由基分子内转化为闭壳产物的新自终止路径相结合,发现了烯二炔和烯炔的四种原型环芳构化的最后一个缺失的例子。芳香烯炔光激发到扭曲的烯烃三重态创造了一种独特的立体电子情况,这是由苯环的激发态反芳香性的释放所促进的。这使得通常不利的 5-endo-trig 环化成为可能,并将其与 5-exo-dig 闭合合并。C1-C5 环化的 1,4-双基产物经历内部 H 原子转移,并伴随着环外 CC 键的断裂。该序列提供了从烯炔获得苯并富烯的有效途径,并将自终止芳构化烯炔级联的效用扩展到光化学反应。这种自终止反应的关键特征是,尽管在关键环化步骤中涉及自由基物质,但不需要外部自由基源或猝灭剂来提供产物。在这些级联中,两个自由基中心都是瞬时形成的,并通过分子内氢转移和 CC 键断裂转化为闭壳产物。此外,将 CC 键裂解结合到烯炔的光化学自终止环化中为在有机合成中使用烯烃作为炔烃等价
Unravelling a bench-stable zinc-amide compound as highly active multitasking catalyst for radical-mediated selective alk(en)ylation of unactivated carbocycles under mild conditions
作者:Sangita Sahoo、Subarna Manna、Arnab Rit
DOI:10.1039/d3sc06334h
日期:——
compound bearing an amidated imidazolium salt towards C–C bond-forming reactions utilizing an array of alcohols, ranging from aliphatic to aromatic and, attractively, even secondary alcohols. Moreover, this readily scalable protocol, which proceeds via an underdeveloped radical-mediated borrowinghydrogen protocol (an aldehyde is generated from an alcohol, and subsequent condensation with indene/fluorene
The condensation of indene or 2-nitrofluorene with aromatic aldehydes catalyzed by bis-(p-methoxyphenyl)telluroxide (BMPTO) under ultrasonic wave irradiation gave corresponding fulvenes in fair to good yield.
Kresze,G. et al., Justus Liebigs Annalen der Chemie, 1964, vol. 674, p. 18 - 27
作者:Kresze,G. et al.
DOI:——
日期:——
The Missing C<sub>1</sub>–C<sub>5</sub> Cycloaromatization Reaction: Triplet State Antiaromaticity Relief and Self-Terminating Photorelease of Formaldehyde for Synthesis of Fulvenes from Enynes
作者:Rana K. Mohamed、Sayantan Mondal、Kjell Jorner、Thais Faria Delgado、Vladislav V. Lobodin、Henrik Ottosson、Igor V. Alabugin
DOI:10.1021/jacs.5b07448
日期:2015.12.16
example of the four archetypical cycloaromatizations of enediynes and enynes was discovered by combining a twisted alkene excited state with a new self-terminating path for intramolecular conversion of diradicals into closed-shell products. Photoexcitation of aromatic enynes to a twisted alkene triplet state creates a unique stereoelectronic situation, which is facilitated by the relief of excited state
通过将扭曲的烯烃激发态与用于双自由基分子内转化为闭壳产物的新自终止路径相结合,发现了烯二炔和烯炔的四种原型环芳构化的最后一个缺失的例子。芳香烯炔光激发到扭曲的烯烃三重态创造了一种独特的立体电子情况,这是由苯环的激发态反芳香性的释放所促进的。这使得通常不利的 5-endo-trig 环化成为可能,并将其与 5-exo-dig 闭合合并。C1-C5 环化的 1,4-双基产物经历内部 H 原子转移,并伴随着环外 CC 键的断裂。该序列提供了从烯炔获得苯并富烯的有效途径,并将自终止芳构化烯炔级联的效用扩展到光化学反应。这种自终止反应的关键特征是,尽管在关键环化步骤中涉及自由基物质,但不需要外部自由基源或猝灭剂来提供产物。在这些级联中,两个自由基中心都是瞬时形成的,并通过分子内氢转移和 CC 键断裂转化为闭壳产物。此外,将 CC 键裂解结合到烯炔的光化学自终止环化中为在有机合成中使用烯烃作为炔烃等价
Anticancer compounds. Further analogs of 1-(4-dimethylaminobenzylidene)indene
作者:Carl T. Bahner、Norma H. Bingham、David H. Brotherton、Jane Cline、Dan Darby、Harry D. Harmon、Lydia M. Rives、Bill L. Stump、L. Watson