ChemInform Abstract: A Facile Approach to Asymmetrical Biaryls via Coupling Reaction of Aryl Halides with Sodium Tetraphenylborate Catalyzed by MCM-41-Supported Sulfur Palladium(0) Complex.

ChemInform ◽  
2008 ◽  
Vol 39 (18) ◽  
Author(s):  
Qiu Hua Xu ◽  
Ping Ping Wang ◽  
Ming Zhong Cai
Keyword(s):  
Coupling Reaction ◽  
Aryl Halides ◽  
Sodium Tetraphenylborate ◽  
Mcm 41

Synthesis of terminal arylacetylenes by a Stille coupling reaction catalysed by a MCM-41-supported bidentate phosphine palladium(O) complex

2008 ◽  
Vol 2008 (11) ◽  
pp. 615-618 ◽  
Author(s):  
Wenyan Hao ◽  
Yue Wang ◽  
Shouri Sheng ◽  
Mingzhong Cai
Keyword(s):  
Aqueous Medium ◽  
Palladium Catalyst ◽  
Basic Problem ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Stille Coupling ◽  
Bidentate Phosphine ◽  
Stille Coupling Reaction ◽  
High Yields ◽  
Mcm 41

A variety of terminal arylacetylenes have been conveniently synthesised in good to high yields by Stille coupling of aryl halides with ethynyltributylstannane catalysed by a MCM-41-supported bidentate phosphine palladium(O) complex in an aqueous medium and under air. Our system not only avoids the requirement for water-free and oxygen-free conditions, but also solves the basic problem of palladium catalyst reuse.

Piperazine as an Inexpensive and Efficient Ligand for Pd-Catalyzed Homocoupling Reactions to Synthesize Bipyridines and Their Analogues

2019 ◽  
Vol 16 (1) ◽  
pp. 173-180
Author(s):  
Mingwei Chen ◽  
Jinyu Hu ◽  
Xiaoli Tang ◽  
Qiming Zhu
Keyword(s):  
Transition Metal ◽  
Oxidation State ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Metal Species ◽  
Good Substrate ◽  
Active Metal ◽  
Homocoupling Reaction ◽  
Catalytic Cycles ◽  
Reductive Homocoupling

Aim and Objective: The synthesis of bipyridines, especially 2, 2’-bipyridines, remains challenging because the catalytic cycle can be inhibited due to coordination of bipyridine to transition metal. Thus, the development of efficient methods for the synthesis of bipyridines is highly desirable. In the present work, we presented a promising approach for preparation of bipyridines via a Pd-catalyzed reductive homocoupling reaction with simple piperazine as a ligand. Materials and Methods: Simple and inexpensive piperazine was used as a ligand for Pd-catalyzed homocoupling reaction. The combination of Pd(OAc)2 and piperazine in dimethylformamide (DMF) was observed to form an excellent catalyst and efficiently catalyzed the homocoupling of azaarenyl halides, in which DMF was used as the solvent without excess reductants although stoichiometric reductant was generally required to generate the low-oxidation-state active metal species in the catalytic cycles. </P><P> Results: In this case, good to excellent yields of bipyridines and their (hetero) aromatic analogues were obtained in the presence of 2.5 mol% of Pd(OAc)2 and 5 mol% of piperazine, using K3PO4 as a base in DMF at 140°C. Conclusion: According to the results, piperazine as an inexpensive and efficient ligand was used in the Pd(OAc)2-catalyzed homocoupling reaction of heteroaryl and aryl halides. The coupling reaction was operationally simple and displayed good substrate compatibility.

Sign in / Sign up

Export Citation Format

Share Document