Palladium-catalyzed allylic C–H oxidation under simple operation and mild conditions

2019 ◽  
Vol 17 (12) ◽  
pp. 3103-3107 ◽  
Author(s):  
Yunlong Guo ◽  
Zengming Shen

We discovered an effective and simple system (Pd/BQ/air/r.t.) for making allylic alcohols through Pd-catalyzed allylic C–H bond functionalization.

2017 ◽  
Author(s):  
Haibo Ge ◽  
Lei Pan ◽  
Piaoping Tang ◽  
Ke Yang ◽  
Mian Wang ◽  
...  

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp<sup>3</sup> carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp<sup>3</sup>)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp<sup>3</sup>)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.<br><br>


2020 ◽  
Vol 59 (46) ◽  
pp. 20394-20398
Author(s):  
Ji Yang ◽  
Jiawang Liu ◽  
Yao Ge ◽  
Weiheng Huang ◽  
Helfried Neumann ◽  
...  

Author(s):  
Shuangshuang Li ◽  
Ju Qiu ◽  
Bowen Li ◽  
Zuolian Sun ◽  
Peizhong Xie ◽  
...  

A practical palladium/calcium catalytic system was developed for dehydrative allylation concerning unactivated allylic alcohols. EtOH solvent with H2O additive was identified as powerful media to accelerate proton transfer. That catalytic...


Synthesis ◽  
2020 ◽  
Author(s):  
Narendra R. Chaubey ◽  
Anant R. Kapdi ◽  
Biswanath Maity

AbstractOrganophotocatalytic C–H bond functionalization has attracted a lot of attention in the past several years due to the possibility of catalyzing reactions in a metal- and peroxide-free environment. Continuing on these lines, an organophotoredox-catalyzed C–H functionalization of imidazo[1,2-a]pyridines and related heterocycles with bromomalonates under mild conditions is reported, providing excellent yields of the products at room temperature. This is the first report involving malonates as coupling partners leading to the synthesis of a range of functionalized products including total synthesis of zolpidem, a sedative­-hypnotic drug molecule.


1998 ◽  
Vol 76 (10) ◽  
pp. 1467-1473 ◽  
Author(s):  
Veranja Karunaratne ◽  
David Dolphin

A variety of substituted 2-methylpyrroles (3-8) were oxidized using the metalloporphyrin catalysts iron(III) meso-tetra(2,6-dichloro-3-sulphonatophenyl)-β-octachloroporphyrin chloride 1 and iron(III) meso-tetra(2,6-dichlorophenyl)-β-octachloroporphyrin chloride 2 under very mild conditions. Treatment of the resulting allylic alcohols 3a-8a with α-free pyrroles 9 and 10 resulted in a very efficient synthesis of the corresponding dipyrromethanes 3b-8b and 3c-8c. Furthermore, the above allylic alcohols when treated with furfurylamine produced the novel (2-furylmethyl)-2-pyrrolylmethylamines 3d-8d.Key words: catalytic oxidation, metalloporphyrins, pyrroles, dipyrromethanes, polyhalogenated porphyrins.


2006 ◽  
Vol 25 (20) ◽  
pp. 4846-4849 ◽  
Author(s):  
Pascale Crochet ◽  
Mariano A. Fernández-Zúmel ◽  
José Gimeno ◽  
Marcus Scheele

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