作者:Mingyue Zhao、Alejandro G. Barrado、Kristin Sprenger、Christopher Golz、Ricardo A. Mata、Manuel Alcarazo
DOI:10.1021/acs.orglett.0c01204
日期:2020.7.2
A variety of appropriately substituted internal alkynes were transformed into the corresponding cyano-substituted phenanthrenes, dihydronaphthalenes, and cyclohepta-1,3,5-trienes in moderate to excellent yields by treatment with imidazolium thiocyanate 1, which serves as an easy to handle [CN]+ precursor, in the presence of BCl3. The synthetic value of the method is additionally demonstrated by the
Flexible Synthesis of Phenanthrenes by a PtCl<sub>2</sub>-Catalyzed Cycloisomerization Reaction
作者:Alois Fürstner、Victor Mamane
DOI:10.1021/jo025962y
日期:2002.8.1
Readily available biphenyl derivatives containing an alkyne unit at one of their ortho positions are converted into substituted phenanthrenes upon exposure to catalytic amounts of either PtCl(2), AuCl(3), GaCl(3), or InCl(3) in toluene. This 6-endo-dig cyclization likely proceeds through initial pi-coordination of the alkyne unit followed by interception of the resulting eta(2)-metal complex by the
作者:Vladimir Akhmetov、Mikhail Feofanov、Dmitry I. Sharapa、Konstantin Amsharov
DOI:10.1021/jacs.1c07845
日期:2021.9.22
alkynes is the key feature of carbophilic π-Lewis acids such as gold- and platinum-based catalysts. The unique catalytic activity of these compounds in electrophilic activations of alkynes is explained through relativistic effects, enabling efficient orbital overlapping with π-systems. For this reason, it is believed that noble metals are indispensable components in the catalysis of such reactions. In this
Silver-Catalyzed Tandem C≡C Bond Hydroazidation/Radical Addition/Cyclization of Biphenyl Acetylene: One-Pot Synthesis of 6-Methyl Sulfonylated Phenanthridines
作者:Jiawei Tang、Paramasivam Sivaguru、Yongquan Ning、Giuseppe Zanoni、Xihe Bi
DOI:10.1021/acs.orglett.7b01771
日期:2017.8.4
silver-catalyzed tandem carbon–carbon triple bond hydroazidation, radical addition, and cyclization of biphenyl acetylene is described under mild conditions, leading to the formation of 6-methyl sulfonylated phenanthridines in good yields. In this novel cascade reaction, most of the atoms are incorporated into the product without cleavage of the C≡C bond. Mechanistic studies suggest the reaction should proceed
Gold-Catalyzed Regiospecific C−H Annulation of <i>o</i>
-Ethynylbiaryls with Anthranils: π-Extension by Ring-Expansion En Route to N-Doped PAHs
作者:Zhongyi Zeng、Hongming Jin、Kohei Sekine、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/anie.201802445
日期:2018.6.4
and atom economy, and shows good functional‐group compatibility as well as scale‐up potential. Mechanistically, the tandem reaction is proposed to involve a nucleophilic addition/ring opening/regiospecific C−H annulation/protodeauration sequence terminated by a Friedel–Crafts‐type cyclization. Photophysical studies of the products indicated violet‐blue fluorescence emission with quantum yields up to