- A green protocol for ligand, copper and base free Sonogashira cross-coupling reaction
-
A convenient methodology has been developed for palladium catalyzed Sonogashira cross-coupling reaction under mild and green reaction conditions. The reaction is catalyzed by an in situ generated catalytic system based on Pd(OAc)2and WEB (water extract of banana peels ash) in the absence of any organic or inorganic base, ligand and copper salt with excellent yield of cross coupled product. The reaction condition is compatible with electronically diversified aryl iodides and electronically diversified aryl or aliphatic alkyne. The present method developed for the Sonogashira reaction offers many advantages including high conversion, high economy, the involvement of non-toxic green substrates, etc.
- Dewan, Anindita,Sarmah, Manashi,Bora, Utpal,Thakur, Ashim J.
-
-
Read Online
- Alkylation of 1-alkynes in THF
-
Alkynes may be easily alkylated by sequential treatment with n-BuLi followed by an alkyl halide in THF. Primary iodides give excellent yields (75-99%) as do bromides in the presence of catalytic amounts of Bu4NI or NaI; in the absence of an iodide source, bromides react poorly. This method offers advantages over existing methods which use HMPA or NH3 as co-solvents.
- Buck, Matthew,Chong
-
-
Read Online
- Effect of fluorine substituents on catalytic functionalizations of alkyl halides with organostannanes
-
Introduction of fluorine atom(s) at the γ- and δ-positions of alkyl iodides increased the selectivities toward palladium-catalyzed cross-coupling reaction with organostannanes. A similar effect of fluorine substituents on the selectivities was also observed in the palladium-catalyzed carbonylative coupling reaction of alkyl iodides with phenyltributyltin under CO pressure.
- Shimizu, Rie,Fuchikami, Takamasa
-
-
Read Online
- Water-stabilized three- and four-atom palladium clusters as highly active catalytic species in ligand-free C-C cross-coupling reactions
-
Elite cliques: Palladium clusters with three and four atoms were found to be the catalytically active species for ligand-free palladium-catalyzed C-C bond-forming reactions (see picture). These palladium cluster species could be stabilized in water and stored for long periods of time for use on demand with no loss of activity. High yields of products and turnover frequencies (TOFs) of up to 105 h-1 were observed. Copyright
- Leyva-Perez, Antonio,Oliver-Meseguer, Judit,Rubio-Marques, Paula,Corma, Avelino
-
-
Read Online
- Urea as mild and efficient additive for palladium catalyzed Sonogashira cross coupling reaction
-
A catalytic system based on Pd(OAc)2/urea has been developed for Sonogashira cross coupling of aryl halides with terminal alkynes at room temperature. This catalytic system effectively promotes Sonogashira coupling of both aryl iodides and aryl bromides to give polyfunctional alkynes under copper and amine free conditions. The catalytic system is readily accessible, inexpensive and highly flexible for both aromatic and aliphatic alkynes.
- Sarmah, Manashi,Dewan, Anindita,Thakur, Ashim J.,Bora, Utpal
-
-
Read Online
- C-S Bond Alkynylation of Diaryl Sulfoxides with Terminal Alkynes by Means of a Palladium-NHC Catalyst
-
Sonogashira-Hagihara-type alkynylation of diaryl sulfoxides with unactivated terminal alkynes has been developed. With a combination of a palladium-NHC catalyst and LiO t Bu as a base, a series of diaryl sulfoxides were converted into the alkynylated products via C-S bond cleavage.
- Yoshida, Yuto,Nogi, Keisuke,Yorimitsu, Hideki
-
-
Read Online
- Binuclear Pd(I)-Pd(I) Catalysis Assisted by Iodide Ligands for Selective Hydroformylation of Alkenes and Alkynes
-
Since its discovery in 1938, hydroformylation has been thoroughly investigated and broadly applied in industry (>107 metric ton yearly). However, the ability to precisely control its regioselectivity with well-established Rh- or Co-catalysts has thus far proven elusive, thereby limiting access to many synthetically valuable aldehydes. Pd-catalysts represent an appealing alternative, yet their use remains sparse due to undesired side-processes. Here, we report a highly selective and exceptionally active catalyst system that is driven by a novel activation strategy and features a unique Pd(I)-Pd(I) mechanism, involving an iodide-assisted binuclear step to release the product. This method enables β-selective hydroformylation of a large range of alkenes and alkynes, including sensitive starting materials. Its utility is demonstrated in the synthesis of antiobesity drug Rimonabant and anti-HIV agent PNU-32945. In a broader context, the new mechanistic understanding enables the development of other carbonylation reactions of high importance to chemical industry.
- Zhang, Yang,Torker, Sebastian,Sigrist, Michel,Bregovi?, Nikola,Dydio, Pawe?
-
supporting information
p. 18251 - 18265
(2020/11/02)
-
- Gold-Catalyzed Hydrofluorination of Internal Alkynes Using Aqueous HF
-
The gold-catalyzed hydrofluorination reaction of internal alkynes using hydrofluoric acid is reported. Notably, those conditions use one of the most economical sources of HF and are free of additional additives. Both symmetrical and unsymmetrical internal alkynes can be utilized, and the use of alkynes bearing a fluorinated group at the propargylic position as substrates allowed for a regioselective hydrofluorination reaction.
- Gauthier, Rapha?l,Mamone, Marius,Paquin, Jean-Fran?ois
-
supporting information
p. 9024 - 9027
(2019/11/14)
-
- Agro waste derived nanosilica supported Pd(ll) complex: A protocol for copper free Sonogashira reaction in water
-
A palladium (II) complex immobilized onto nanosilica(Pd-imine@nanoSiO2) has been developed and evaluated as a highly efficient, retrievable catalyst for carbon-carbon triple bond activation reactions between aryl halides and terminal alkynes. Nanosilica has been derived from rice husk by simple and eco-compatible methodology. The catalyst has been extensively characterized by techniques such as FT-IR, UV–vis, powder XRD, XPS, SEM-EDX, thermogravimetric analysis, BET surface area measurement. The catalyst can be reused for five consecutive runs without compromising much with the activity. Easy preparation, its long shelf life, air-stability, wide substrate scope, ‘in water’ reactions, easy separability and good recyclability make it an ideal system for Sonogashira cross-coupling reaction. Moreover, various alkyne substrates were efficiently cross-coupled with a broad range of aryl iodides and aryl bromides to afford diaryl alkynes, providing improved yields with low catalyst loading in water. This protocol is also suitable for aliphatic alkynes.
- Gogoi, Rajjyoti,Saikia, Rituraj,Borah, Geetika
-
-
- A palladium salen complex: An efficient catalyst for the Sonogashira reaction at room temperature
-
A tetradentate Schiff base derived palladium complex has been developed as a catalyst for the room temperature Sonogashira reaction under copper free conditions. The main catalytic species, a Pd-complex was derived from Schiff base ligand N,N′-bis(salicylidene)-arylmethanediamine and Pd(OAc)2. Electron rich, electron deficient and sterically hindered aryl iodides underwent smooth coupling to afford good to excellent yield of diaryl alkynes in isopropanol at room temperature. The protocol is also suitable for aliphatic alkynes.
- Gogoi, Ankur,Dewan, Anindita,Borah, Geetika,Bora, Utpal
-
supporting information
p. 3341 - 3344
(2015/05/20)
-
- ALKYLATION OF STABILIZED ACETYLIDES IN DMSO. PREPARATION OF α,β-ACETYLENIC ALCOHOLS AND ACETALS.
-
Stabilized terminal acetylenes 1 2OTHP, Ph, CH(OET)2> may be converted into lithioacetylides and readily alkylated with 1 alkyl halides in DMSO to afford functionalized disubstitued acetylenes.
- Chong, J. Michael,Wong, Susanna
-
p. 5445 - 5448
(2007/10/02)
-