protocol for the construction of 9-(diorganomethylidene)fluorenes through palladium-catalyzed coupling reactions of 2-iodobiphenyls with alkenyl bromides has been reported. The reaction proceeds through the C–H activation/oxidative addition/reduction elimination/intramolecular Heck coupling reaction to afford a series of 9-(diorganomethylidene)fluorenes with good yields. Control experiments demonstrate that
central goal in catalysis. This would be especially interesting when the reactivity and selectivity patterns can be tuned. Herein, we introduced the first Mn-catalyzed selective C-alkylation and olefination of fluorene, and indene with alcohols. Various substrates including benzylic, heteroaromatic, and aliphatic primary and secondary alcohols are employed as alkylating agents. Mechanistic investigations
Intermolecular Oxidative Friedel–Crafts Reaction Triggered Ring Expansion Affording 9,10-Diarylphenanthrenes
作者:Lu Yang、Ilya D. Gridnev、Masahiro Terada、Tienan Jin
DOI:10.1021/acs.orglett.0c03283
日期:2020.11.20
A novel intermolecular tandem oxidative aromatic coupling between arylidene fluorenes and unfunctionalized aromatics mediated by a DDQ/TFA oxidation system has been developed for the construction of 9,10-diarylphenanthrenes (DAPs). The formation of a benzylic carbocation species possessing a quaternary sp3-carbon center on the fluorene moiety by an intermolecular oxidative Friedel–Crafts reaction of
Dications of Benzylidenefluorene and Diphenylmethylidene Fluorene: The Relationship between Magnetic and Energetic Measures of Antiaromaticity
作者:Catherine Do、Julianne Hatfield、Shirali Patel、D. Vasudevan、Cornelia Tirla、Nancy S. Mills
DOI:10.1021/jo101871q
日期:2011.1.7
Oxidation of m- and p-substituted benzylidene fluorenes to antiaromatic dications was attempted by electrochemical and chemical means. Electrochemical oxidation to dications was successful for benzylidene fluorenes with p-methoxy, p-methyl, p-fluoro, and unsubstituted phenyl rings in the 3-position; attempts to oxidize the m-substituted derivatives via electrochemistry were unsuccessful. Chemical oxidation
通过电化学和化学方法试图将间和对位取代的亚苄基芴氧化成抗芳族化合物。对于在3位上有对甲氧基,对甲基,对氟和未取代的苯环的亚苄基芴,电化学氧化成指示剂是成功的。尝试以氧化米取代经由电化学衍生物是不成功的。用SbF 5 / SO 2 ClF化学氧化得到9-[((4-甲氧基苯基)亚甲基] -9 H-干净的芴;所有其他取代的亚苄基芴的氧化产生产物混合物。GIAO方法计算出的化学位移与p-甲氧基取代的亚苄基芴指示表明,该计算令人满意地反映了该指示剂的磁性,并可能反映了所研究的其他指示剂的磁性。来自电化学氧化的氧化还原电势(一种指示剂的稳定性的度量)与另一种稳定性度量(每个指示剂与其中性前体之间的能量差计算值)显示出良好的线性关系。亚苄基芴的指示剂不如二苯基亚甲基芴的指示剂稳定。在每种类型的化合物中,带有p取代苯环的化合物比带有m的化合物更稳定。取代的苯环和带有被给电子基团取代的苯环的指示剂比带有被吸
Manganese-Catalyzed Synthesis of Quaternary Peroxides: Application in Catalytic Deperoxidation and Rearrangement Reactions
作者:Akash S. Ubale、Moreshwar B. Chaudhari、Moseen A. Shaikh、Boopathy Gnanaprakasam
DOI:10.1021/acs.joc.0c00837
日期:2020.8.21
method effectively promotes the vicinal bisperoxidation of sterically hindered various substituted arylidene-9H-fluorene/arylideneindolin-2-one derivatives to afford highly substituted bisperoxides with high selectivity over the oxidative cleavage of C═C bond that usually forms the ketone of an aldehyde. Furthermore, a new approach for the synthesis of (Z)-6-benzylidene-6H-benzo[c]chromene has been achieved