Synthesis of Substituted [6]Phenacenes through Suzuki–Miyaura Coupling of Polyhalobenzene with Alkenylboronates and Sequential Intramolecular Cyclization via C–H Bond Activation

2013 ◽  
Vol 42 (10) ◽  
pp. 1257-1259 ◽  
Author(s):  
Ning-hui Chang ◽  
Hiroki Mori ◽  
Xi-chao Chen ◽  
Yasuhiro Okuda ◽  
Takeru Okamoto ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
Bond Activation

Direct access to isoindolines through tandem Rh(iii)-catalyzed alkenylation and cyclization of N-benzyltriflamides

2014 ◽  
Vol 50 (18) ◽  
pp. 2350-2352 ◽  
Author(s):  
Neeraj Kumar Mishra ◽  
Jihye Park ◽  
Satyasheel Sharma ◽  
Sangil Han ◽  
Mirim Kim ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
Bond Activation ◽  
Direct Access

The rhodium-catalyzed oxidative alkenylation of N-benzyltriflamides with olefins followed by an intramolecular cyclization via C–H bond activation is described.

Transition-metal-free C–C σ-bond activation of α-aryl ketones and subsequent Zn-catalyzed intramolecular cyclization: synthesis of tetrasubstituted furans

2019 ◽  
Vol 17 (10) ◽  
pp. 2725-2733 ◽  
Author(s):  
Yang Yuan ◽  
Hailu Tan ◽  
Lingkai Kong ◽  
Zhong Zheng ◽  
Murong Xu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Intramolecular Cyclization ◽  
Bond Activation ◽  
Metal Free ◽  
Aryl Ketones ◽  
Single Bonds

Atom-economical synthesis of tetrasubstituted furans from α-aryl ketones and alkynones through base-promoted cleavage of unstrained C–C single bonds of ketones and subsequent Zn-catalyzed cyclization.

Efficient synthesis and preliminary biological evaluations of trifluoromethylated imidazo[1,2-a]pyrimidines and benzimidazo[1,2-a]pyrimidines

2019 ◽  
Vol 43 (25) ◽  
pp. 9961-9968
Author(s):  
Badr Jismy ◽  
Mohamed Akssira ◽  
Damijan Knez ◽  
Gérald Guillaumet ◽  
Stanislav Gobec ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
Michael Addition ◽  
Bond Activation ◽  
Cyclization Reaction ◽  
Efficient Synthesis ◽  
Imidazole Derivatives ◽  
Amino Imidazole

Fluoromethylated imidazo[1,2-a]pyrimidines and benzimidazo[1,2-a]pyrimidines were synthesized through Michael addition/intramolecular cyclization reaction by condensation of 2-amino imidazole derivatives with ethyl 4,4,4-trifluorobut-2-ynate and using C–O bond activation.

Metal-Metal Cooperative Bond Activation by Heterobimetallic Alkyl, Aryl, and Acetylide PtII/CuI Complexes

2020 ◽  
Author(s):  
Shubham Deolka ◽  
Orestes Rivada Wheelaghan ◽  
Sandra Aristizábal ◽  
Robert Fayzullin ◽  
Shrinwantu Pal ◽  
...  
Keyword(s):  
Alkyl Group ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Terminal Alkyne ◽  
Alkyl Aryl ◽  
Metal Metal ◽  
The Stability ◽  
Selective Formation ◽  
Organoplatinum Compounds

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.

Imine as a Linchpin Approach for Distal C(sp2)–H Functionalization

2020 ◽  
Author(s):  
Sukdev Bag ◽  
Sadhan Jana ◽  
Sukumar Pradhan ◽  
Suman Bhowmick ◽  
Nupur Goswami ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Bond Activation ◽  
Bond Formation ◽  
Ancillary Ligand ◽  
Significant Challenge ◽  
Site Selectivity ◽  
Directing Group ◽  
Covalently Linked ◽  
Complex Organic ◽  
Post Functionalization

<p>Despite the widespread applications of C–H functionalization, controlling site selectivity remains a significant challenge. Covalently attached directing group (DG) served as an ancillary ligand to ensure proximal <i>ortho</i>-, distal <i>meta</i>- and <i>para</i>-C-H functionalization over the last two decades. These covalently linked DGs necessitate two extra steps for a single C–H functionalization: introduction of DG prior to C–H activation and removal of DG post-functionalization. We introduce here a transient directing group for distal C(<i>sp<sup>2</sup></i>)-H functionalization <i>via</i> reversible imine formation. By overruling facile proximal C-H bond activation by imine-<i>N</i> atom, a suitably designed pyrimidine-based transient directing group (TDG) successfully delivered selective distal C-C bond formation. Application of this transient directing group strategy for streamlining the synthesis of complex organic molecules without any necessary pre-functionalization at the distal position has been explored.</p>

Pt-Pd Nanoalloy for the Unprecedented Activation of Carbon-Fluorine Bond at Low Temperature

2019 ◽  
Author(s):  
Raghu Nath Dhital ◽  
keigo nomura ◽  
Yoshinori Sato ◽  
Setsiri Haesuwannakij ◽  
Masahiro Ehara ◽  
...  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Dft Calculations ◽  
Bond Activation ◽  
Mild Conditions ◽  
Selective Transformation ◽  
Rate Determining Step ◽  
Highly Active ◽  
Harsh Conditions ◽  
Reaction Profile

Carbon-Fluorine (C-F) bonds are considered the most inert organic functionality and their selective transformation under mild conditions remains challenging. Herein, we report a highly active Pt-Pd nanoalloy as a robust catalyst for the transformation of C-F bonds into C-H bonds at low temperature, a reaction that often required harsh conditions. The alloying of Pt with Pd is crucial to activate C-F bond. The reaction profile kinetics revealed that the major source of hydrogen in the defluorinated product is the alcoholic proton of 2-propanol, and the rate-determining step is the reduction of the metal upon transfer of the <i>beta</i>-H from 2-propanol. DFT calculations elucidated that the key step is the selective oxidative addition of the O-H bond of 2-propanol to a Pd center prior to C-F bond activation at a Pt site, which crucially reduces the activation energy of the C-F bond. Therefore, both Pt and Pd work independently but synergistically to promote the overall reaction

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