Synthesis of Fluorenes<i>via</i>the Palladium-Catalyzed 5-<i>exo-dig</i>Annulation of<i>o</i>-Alkynylbiaryls
作者:Natalia Chernyak、Vladimir Gevorgyan
DOI:10.1002/adsc.200800765
日期:2009.5
The direct Pd-catalyzed intramolecular rapidly with electron-deficient benzene ring, which, in hydroarylation of o-alkynyl biaryls proceeded in highly combination with a substantial isotope effect observed, stereoselective manner producing fluorenes 2, the products of 5-exo-dig cyclization, in excellent yields. The cascade intermolecular arylation, incorporated in this transformation, allowed for efficient
Nitration and Cyclization of Arene-Alkynes: An Access to 9-Nitrophenathrenes
作者:Wangsheng Liu、Yanbin Zhang、Hao Guo
DOI:10.1021/acs.joc.8b01201
日期:2018.9.7
A nitration and cyclization of arene-alkynes has been developed, affording 9-nitrophenathrenes efficiently. This reaction probably proceeds via addition of the nitrogen dioxide to the alkyne moiety, intramolecular radical addition of vinyl radical to one aryl ring, oxidation of radical intermediate into carbocation species, and elimination of a proton. In this transformation, Fe(NO3)3 was used as both
We describe a novel and highly efficient metal-free strategy to construct 9,9-disubstituted fluorenes and phenanthrenes via the TfOH-catalyzed cycloisomerizations of o-alkynylbiaryls. Notably, the significant effects of the electronic properties and steric hindrance of the alkyne terminus on the reaction selectivity have been observed.
Synthesis of Polycyclic Aromatic Iodides via ICl-Induced Intramolecular Cyclization
作者:Tuanli Yao、Marino A. Campo、Richard C. Larock
DOI:10.1021/ol049161o
日期:2004.8.1
The reaction of 2-(arylethynyl)biphenyls with ICl at -78 degrees C affords substituted polycyclic aromatic iodides in good to excellent yields. The aryl substituents can be either electron-donating or electron-withdrawing groups such as OMe, Me, CHO, CO(2)Et or NO(2) groups. This chemistry has been successfully extended to systems containing a variety of polycyclic and heterocyclic rings. [reaction:
Exclusive 5-<i>exo-dig</i> Hydroarylation of <i>o</i>-Alkynyl Biaryls Proceeding via C−H Activation Pathway
作者:Natalia Chernyak、Vladimir Gevorgyan
DOI:10.1021/ja8006534
日期:2008.4.1
The first example of the palladium-catalyzed exclusive 5-exo-dig hydroarylation of o-alkynyl biaryls has been demonstrated. In contrast to the reported earlier carbocyclizations proceeding via the Friedel-Crafts mechanism, this hydroarylation efficiently proceeds with electron-neutral and electron-deficient arenes, producing fluorene frameworks with defined stereochemistry of the double bond. On the