Iridium-Catalyzed C–H Alkylative Annulation of Arenes Using Ketones as an Alkyl Radical Source

Synfacts ◽  
2021 ◽  
Vol 17 (12) ◽  
pp. 1346
Keyword(s):  
2019 ◽  
Author(s):  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff ◽  
Frank Glorius

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chia-Yu Huang ◽  
Jianbin Li ◽  
Chao-Jun Li

AbstractHydrogen atom abstraction (HAT) from C(sp3)–H bonds of naturally abundant alkanes for alkyl radical generation represents a promising yet underexplored strategy in the alkylation reaction designs since involving stoichiometric oxidants, excessive alkane loading, and limited scope are common drawbacks. Here we report a photo-induced and chemical oxidant-free cross-dehydrogenative coupling (CDC) between alkanes and heteroarenes using catalytic chloride and cobalt catalyst. Couplings of strong C(sp3)–H bond-containing substrates and complex heteroarenes, have been achieved with satisfactory yields. This dual catalytic platform features the in situ engendered chlorine radical for alkyl radical generation and exploits the cobaloxime catalyst to enable the hydrogen evolution for catalytic turnover. The practical value of this protocol was demonstrated by the gram-scale synthesis of alkylated heteroarene with merely 3 equiv. alkane loading.


2021 ◽  
Vol 133 (17) ◽  
pp. 9792-9797
Author(s):  
Ming‐Qing Tian ◽  
Zhen‐Yao Shen ◽  
Xuefei Zhao ◽  
Patrick J. Walsh ◽  
Xu‐Hong Hu

2009 ◽  
Vol 113 (8) ◽  
pp. 1564-1573 ◽  
Author(s):  
Barbara Bankiewicz ◽  
Lam K. Huynh ◽  
Artur Ratkiewicz ◽  
Thanh N. Truong

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3517
Author(s):  
Horst Berneth ◽  
Friedrich Karl Bruder ◽  
Thomas Fäcke ◽  
Sven Hansen ◽  
Koichi Kawamura ◽  
...  

Versatile substituted electron-deficient trichloromethylarenes can easily be synthesized and combined with a Safranine O/triarylalkylborate salt to form a highly efficient three-component photo-initiation system that starts free radical polymerization to finally form holographic gratings with a single-pulsed laser. The mechanism of this photo-initiation most likely relies on an electron transfer from the borate salt into the semi-occupied HOMO of the excited dye molecule Safranine O, which after fragmentation generates an initiating alkyl radical and longer-lived dye radical species. This dye radical is most probably oxidized by the newly introduced trichloromethylarene derivative as an electron acceptor. The two generated radicals from one absorbed photon initiate the photopolymerization and form index gratings in a suitable holographic recording material. This process is purely photonic and does not require further non-photonic post treatments.


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