Regiospecific Palladium-Catalyzed Cross-Coupling Reactions Using the Operational Equivalent of 1,3-Dilithiopropyne

Synthesis ◽  
2020 ◽  
Vol 52 (16) ◽  
pp. 2387-2394 ◽  
Author(s):  
Jorge A. Cabezas ◽  
Natasha Ferllini

A regiospecific palladium-catalyzed cross-coupling reaction using the operational equivalent of the dianion 1,3-dilithiopropyne, with aromatic iodides is reported. This reaction gives high yields of 1-propyn-1-yl-benzenes and 2-(propyn-1-yl)thiophenes in the presence of catalytic amounts of palladium(0) or (II) and stoichiometric amounts of copper iodide. No terminal alkyne or allene isomers were detected. Reaction conditions were very mild and several functional groups were tolerated.

Synlett ◽  
2017 ◽  
Vol 29 (03) ◽  
pp. 330-335 ◽  
Author(s):  
Zheng-Jun Quan ◽  
Xi-Cun Wang ◽  
Ming-Xia Liu ◽  
Hai-Peng Gong

Dihetaryl disulfides were used as electrophiles in a palladium-catalyzed carbon–carbon cross-coupling reaction with arylsilanes to ­realize a Hiyama-type reaction. This unique transformation shows high reactivity, excellent functional-group tolerance, and mild reaction conditions, making it an attractive alternative to conventional cross-coupling approaches for carbon−carbon bond construction.


2020 ◽  
Author(s):  
Chet Tyrol ◽  
Nang Yone ◽  
Connor Gallin ◽  
Jeffery Byers

By using an iron-based catalyst, access to enantioenriched 1,1-diarylakanes was enabled through an enantioselective Suzuki-Miyaura crosscoupling reaction. The combination of a chiral cyanobis(oxazoline) ligand framework and 1,3,5-trimethoxybenzene additive were essential to afford high yields and enantioselectivities in cross-coupling reactions between unactivated aryl boronic esters and a variety of benzylic chlorides, including challenging ortho-substituted benzylic chloride substrates. Mechanistic investigations implicate a stereoconvergent pathway involving carbon-centered radical intermediates.


Synthesis ◽  
2018 ◽  
Vol 50 (09) ◽  
pp. 1883-1890 ◽  
Author(s):  
Margus Lopp ◽  
Eleana Lopušanskaja ◽  
Anne Paju ◽  
Ivar Järving

A method for the synthesis of cyclic 3-aryl- and heteroaryl-substituted 1,2-dicarbonyl compounds with different ring sizes by using a Suzuki cross-coupling reaction between 3-halo-1,2-dicarbonyl compounds and arylboronic acids is developed. The 3-halo-1,2-dicarbonyl substrates are easily available from 1,2-dicarbonyl compounds. The method is versatile, affording good to high yields of the target compounds.


2012 ◽  
Vol 8 ◽  
pp. 2004-2018 ◽  
Author(s):  
Rajendra Surasani ◽  
Dipak Kalita ◽  
A V Dhanunjaya Rao ◽  
K B Chandrasekhar

Simple and efficient procedures for palladium-catalyzed cross-coupling reactions of N-substituted 4-bromo-7-azaindole (1H-pyrrole[2,3-b]pyridine), with amides, amines, amino acid esters and phenols through C–N and C–O bond formation have been developed. The C–N cross-coupling reaction of amides, amines and amino acid esters takes place rapidly by using the combination of Xantphos, Cs2CO3, dioxane and palladium catalyst precursors Pd(OAc)2/Pd2(dba)3. The combination of Pd(OAc)2, Xantphos, K2CO3 and dioxane was found to be crucial for the C–O cross-coupling reaction. This is the first report on coupling of amides, amino acid esters and phenols with N-protected 4-bromo-7-azaindole derivatives.


Synthesis ◽  
2021 ◽  
Author(s):  
Lorenzo Lombardi ◽  
Raffaello Mazzaro ◽  
Massimo Gazzano ◽  
Alessandro Kovtun ◽  
Vittorio Morandi ◽  
...  

A new type of ligand-free Ni-nanoparticles supported on rGO (size distribution average d = 9 ± 3 nm) is prepared and fully characterized via morphological (Fe-SEM), structural (P-XRD, HR-TEM) and spectroscopic (ICP-EOS, XPS) analysis tools. The metal composite was effectively employed in the unprecedented heterogeneously Ni-assisted cross-coupling reaction of aryl/vinyl iodides and thiocarboxylates. A range of sulphur-containing aryl as well as vinyl derivatives (15 examples) was achieved in high yields (up to 82%), mild reaction conditions and wide functional group tolerance.


Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1788
Author(s):  
S. N. Murthy Boddapati ◽  
Ramana Tamminana ◽  
Ravi Kumar Gollapudi ◽  
Sharmila Nurbasha ◽  
Mohamed E. Assal ◽  
...  

A facile, one-pot, and proficient method was developed for the production of various 2-arylaminobenzimidazoles. This methodology is based for the first time on a copper catalyst promoted domino C–N cross-coupling reaction for the generation of 2-arylaminobenzimidazoles. Mechanistic investigations revealed that the synthetic pathway involves a copper-based desulphurization/nucleophilic substitution and a subsequent domino intra and intermolecular C–N cross-coupling reactions. Some of the issues typically encountered during the synthesis of 2-arylaminobezimidazoles, including the use of expensive catalytic systems and the low reactivity of bromo precursors, were addressed using this newly developed copper-catalyzed method. The reaction procedure is simple, generally with excellent substrate tolerance, and provides good to high yields of the desired products.


Synthesis ◽  
2019 ◽  
Vol 51 (22) ◽  
pp. 4153-4164
Author(s):  
Linda M. Bannwart ◽  
Pascal S. Rieder ◽  
Marcel Mayor

Organosulfur compounds are ubiquitous in synthetic chemistry, biology and materials chemistry. The reactivity of free sulfhydryls requires their masking in many synthetic strategies. To facilitate the isolation of protected thiols by chromatography, we propose 2-(3-cyanopropyldimethylsilyl)ethyl as a polar protecting group analogue of 2-(trimethylsilyl)ethyl. The masked thiophenol is obtained in two synthetically complementing ways. Either an existing thiophenol is protected, or the protected thiol group is introduced by a cross-coupling reaction. In both cases the required reagents are readily available from inexpensive starting materials. Thiol protection and thiol introduction both tolerate a large variety of functional groups and substitution patterns, and the protected thiophenols are stable toward a broad range of reaction conditions. The stability of the protected derivatives in cross-coupling reactions and the mild reaction conditions for the release of the protecting group further emphasizes the potential of the methodology.


Synthesis ◽  
2021 ◽  
Author(s):  
chang wen ◽  
Qing Han Li ◽  
Chuan Wu ◽  
ruiqiang Luo ◽  
Feng Chen

A highly efficient and simple route for the synthesis of 2-substituted benzo[b]furans has been developed by Palladium catalyzed the cross-coupling reaction of 2-halobenzo[b]furans with aryl, alkynyl and alkylaluminum reagents. Various 2-aryl, 2-alkynyl and 2-alkyl substituted benzo[b]furans derivatives can be obtained with 23-97% isolated yields using 2-3 mol% PdCl2/ 4-6 mol% XantPhos as the catalyst under mild reaction conditions. The aryls bearing electron-donating or electron-withdrawing groups in 2-halobenzo[b]furans gave products in 40-97% isolated yields. In addition, aluminum reagents containing thienyl, furanyl trimethylsilanyl and benzyl groups worked efficiently with 2-halobenzo[b]furans as well, and three bioactive molecules with 2-substituted benzo[b]furan skeleton were synthesized. Furthermore, the broad substrates scope and the typical maintenance of vigorous efficiency on gram scale make this protocol a potentially practical method to synthesize 2-substituted benzo[b]furans derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.


2014 ◽  
Vol 10 ◽  
pp. 2821-2826 ◽  
Author(s):  
Claudia Araceli Contreras-Celedón ◽  
Darío Mendoza-Rayo ◽  
José A Rincón-Medina ◽  
Luis Chacón-García

A simple and efficient catalytic system based on a Pd complex of 4-aminoantipyrine, 4-AAP–Pd(II), was found to be highly active for Suzuki–Miyaura cross-coupling of aryl iodides and bromides with phenylboronic acids under mild reaction conditions. Good to excellent product yields from the cross-coupling reaction can be achieved when the reaction is carried out in ethanol, in the open air, using low loading of 4-AAP–Pd(II) as a precatalyst, and in the presence of aqueous K2CO3 as the base. A variety of functional groups are tolerated.


Author(s):  
Hany A. Elazab ◽  
Ali R. Siamaki ◽  
B. Frank Gupton ◽  
M. Samy El-Shall

There are several crucial issues that need to be addressed in the field of applied catalysis. These issues are not only related to harmful environmental impact but also include process safety concerns, mass and heat transfer limitations, selectivity, high pressure, optimizing reaction conditions, scale-up issues, reproducibility, process reliability, and catalyst deactivation and recovery. Many of these issues could be solved by adopting the concept of micro-reaction technology and flow chemistry in the applied catalysis field. A microwave assisted reduction technique has been used to prepare well dispersed, highly active Pd/Fe3O4 nanoparticles supported on reduced graphene oxide nanosheets (Pd-Fe3O4/RGO), which act as a unique catalyst for Suzuki cross coupling reactions due to the uniform dispersion of palladium nanoparticles throughout the surface of the magnetite - RGO support. The Pd-Fe3O4/RGO nanoparticles have been shown to exhibit extremely high catalytic activity for Suzuki cross coupling reactions under both batch and continuous reaction conditions. This paper reported a reliable method for Suzuki cross-coupling reaction of 4-bromobenzaldehyde using magnetically recyclable Pd/Fe3O4 nanoparticles supported on RGO nanosheets in a microfluidic-based high throughput flow reactor. Organic synthesis can be performed under high pressure and temperature by using a stainless steel micro tubular flow reactor under continuous flow reaction conditions. Optimizing the reaction conditions was performed via changing several parameters including temperature, pressure, and flow rate. Generally, a scalable flow technique by optimizing the reaction parameters under high-temperature and continuous reaction conditions could be successfully developed.


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