Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate) catalyzed Suzuki, Heck, Sonogashira, and cyanation reactions

Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate): a structurally well-defined O-containing transition metal complex is reported as an efficient catalyst for Suzuki, Heck, and Sonogashira cross-coupling reactions. The protocol was also applied successfully for cyanation of aryl halides under milder operating conditions. The system tolerated the coupling of various aryl halides with alkenes, alkynes, and organoboronic acid along with the cyanation of aryl halides providing good to excellent yields of desired products.     

Application of an air stable Pd oxazoline complex for Heck, Suzuki, Sonogashira and related C-C bond-forming reactions

The novel complex trans-[PdCl₂(η¹-N-2-ethyl-2-oxazoline)₂] is shown to be an active and oxidatively robust catalyst for C-C bond-forming reactions (Heck, Sonogashira, Ullman, Suzuki), which can be carried out in air without rigorous solvent/substrate purification and in the absence of additional free ligand.     

Di(2-pyridyl)methylamine-palladium dichloride complex covalently anchored to a styrene-maleic anhydride co-polymer as recoverable catalyst for C-C cross-coupling reactions in water

A new polymer-supported di(2-pyridyl)methylamine-palladium dichloride complex covalently anchored to a styrene-alt-maleic anhydride co-polymer is prepared. This complex catalyzes Heck, Suzuki and Sonogashira cross-coupling reactions in neat water with similar efficiency than the monomeric complex. The turnover number (TON) of this polymer reaches up to 10⁴ for Heck reactions, whereas for Suzuki and Sonogashira couplings TONs up to 10⁵ are achieved. There is low leaching of palladium after filtration of the polymer and the activity remains almost constant after fourth and five reaction cycles especially in Sonogashira reactions. In the case of the Suzuki reaction Pd nanoparticles are dispersed into the polymer after the first cycle according to TEM images and 2.4% of Pd are found by ICP-OES in the corresponding filtrate. Alternatively, these palladium-catalyzed reactions can also be performed under microwave heating. These couplings take place with better efficiency with polymer-supported di(2-pyridyl)methylamine-palladium dichloride complex than with the polyurea-encapsulated Pd EnCat™ 40.     

Catalytic activities of NHC‐PdCl2 species based on functionalized tetradentate imidazolium salt in three types of C‐C coupling reactions

A functionalized tetradentate imidazolium salt 9,10‐bis{di[2′‐(N‐ethylimidazolium‐1‐yl)ethyl]aminomethyl}anthracene tetrakis(hexafluorophosphate) ( 1 ) has been synthesized and characterized. The catalytic activity of the NHC‐PdCl₂ species formed by compound 1 and PdCl₂ was tested in Suzuki‐Miyaura, Heck‐Mizoroki and Sonogashira reactions. The results showed that this catalytic system was effective for above three types of C‐C coupling reactions.     

原位生成的水溶性Salen-Pd配合物催化微波促进水中的C-C偶联反应

将一种水溶性Salen,N,N’-双[（5-磺酸基-2-羟基）苄基]缩N,N’-二甲基-1,2-乙二胺（L）与醋酸钯原位生成水溶性Salen-Pd配合物,该水溶性钯配合物应用于催化微波加热的水中的Heck和Sonogashira碳-碳偶联反应.在优化反应条件之后,对溴苯衍生物与乙烯衍生物的Heck偶联反应以及溴苯衍生物与苯乙炔及其衍生物之间的Sonogashira偶联反应进行了考察.发现,在优化的反应条件下,无论是Heck反应,还是Sonogashira偶联反应,都能得到很好的收率.在有机物分离之后,水相继续循环使用4次,在水相的前3次循环使用时,都获得了不错的收率.     

Copper- and phosphine-free Sonogashira coupling reactions of aryl iodides catalyzed by an N,N-bis(naphthylideneimino)diethylenetriamine-functionalized polystyrene resin supported Pd(II) complex under aerobic conditions

A polymer-supported palladium(II) N,N-bis(naphthylideneimino)diethylenetriamine complex is found to be a highly active catalyst for Sonogashira coupling reactions. The reactions are performed under copper- and phosphine-free conditions in an air atmosphere. The palladium catalyst is easily separated, and can be reused several times without significant loss in catalytic activity.     

Synthesis of 1H-pyrrolo[3,2-c]quinoline derivatives via palladium-catalyzed heteroannulation of 2-aryl-3-iodo-4-(phenylamino)quinolines and 4-(N,N-allylphenylamino)-2-aryl-3-iodoquinolines

Palladium(0)/copper iodide catalyzed Sonogashira cross-coupling of 2-aryl-3-iodo-4-(phenylamino)quinolines with terminal alkynes afforded series of 1,2,4-trisubstituted 1H-pyrrolo[3,2-c]quinolines in a single-step operation. Conversely, the 4-(N,N-allylphenylamino)-2-aryl-3-iodoquinoline derivatives were found to undergo PdCl₂(PPh₃)₂/CuI catalyzed intramolecular Heck reaction to yield the corresponding 1,3,4-trisubstituted 1H-pyrrolo[3,2-c]quinolines.     

Recyclable and eco-friendly Pd-complexed graphene oxide/N-heterocyclic carbene catalyst for various coupling reactions in aqueous phase

In this study, we report recyclable Pd-complexed graphene oxide (GO) catalysts with a bulky N-heterocyclic carbene (NHC) ligand (GO/NHC-Pd) for various cross-coupling reactions in the aqueous phase. To prepare GO/NHC-Pd, the NHC precursor and a trimethoxy-silane linker were combined on the GO surface via condensation, followed by the Pd chelation over GO/NHC. The GO-based catalysts were applied to three types of CC cross-coupling reactions including Suzuki, Heck and Sonogashira reactions in the aqueous phase, to evaluate their catalytic performance. The reusability of the catalysts was tested by performing five consequent cross-coupling reactions.     

Sulfilimine palladacycles: stable and efficient catalysts for carbon-carbon coupling reactions

A new family of sulfilimine-based palladacycles (1-4) has been synthesized in high yields from easily accessible starting materials and is found to exhibit high catalytic activities for carbon-carbon bond-formation in Suzuki, Heck, Sonogashira and Ullmann-type reactions, affording coupled products in excellent yields.     

Preparation of polystyrene-supported soluble palladacycle catalyst for Heck and Suzuki reactions

A polystyrene-supported palladium complex soluble in tetrahydrofuran and N,N-dimethylacetamide and precipitated in diethyl ether or acetonitrile was prepared from two routes as an excellent and recyclable palladacycle catalyst for carbon-carbon bond formation in Heck and Suzuki reactions to give high yields of the desired products.     

The first example of atropisomeric amide-derived P,O-ligands used for an asymmetric Heck reaction

Atropisomeric N,N-diisopropyl 2-diphenylphosphino- and 2-di(tert-butyl)phosphino-1-naphthamides were used, for the first time, as bidentate P,O-ligands for intermolecular asymmetric Heck reactions of 2,3-dihydrofuran with aryl triflates. The reactions were carried out in the presence of 4 mol% Pd(OAc)₂, 8 mol% of the axially chiral ligand, and 3 equiv. of (i-Pr)₂NEt in THF at 60 °C for 3 days. Optically active 2-aryl-2,5-dihydrofurans were obtained as the major products along with the rearranged 2-aryl-2,3-dihydrofurans. Enantioselectivity up to 55.2% ee was obtained for the major product.     

有氧条件下聚(氯乙烯)负载Pd(II)配合物高效催化Heck和无铜Sonogashira反应Mohammad Bakherad,Ali Keivanloo,Shahrzad Samangooei简

A novel poly(vinyl chloride)-supported Pd complex was found to be a highly active catalyst for the Heck and Sonogashira reactions of aryl halides under aerobic conditions. The complex is thermally stable, and can be easily recovered and reused. The catalyst was recycled for the Heck and Sonogashira reactions for five runs without appreciable loss of its catalytic activity, and with negligible metal leaching.     

Synthesis of carbazoles and 1,2-dihydrocarbazoles by domino ‘twofold Heck/6π-electrocyclization’ reactions of di-, tri- and tetrabromoindoles

Di-, tri- and tetra-alkenylindoles were prepared by palladium(0)-catalyzed Heck cross-coupling reactions of di-, tri- and tetrabromo-N-methylindoles. The reactions were carried out at 90 °C using a novel biaryl monophosphine ligand developed by Buchwald and co-workers. 1,2-Dihydrocarbazoles were formed by a domino ‘twofold Heck/6π-electrocyclization’ when the reaction was carried out at higher temperature. The regioselectivity of the Heck reaction of 2,3,6-tribromo-N-methylindoles was in favour of carbon atoms C-2 and C-3. The 1,2-dihydrocarbazoles were transformed, by Pd/C-catalyzed dehydrogenation, into the corresponding carbazoles in high yield.     

Copper-free Sonogashira cross-coupling reaction catalyzed by polymer-supported N-heterocyclic carbene palladium complex

A core-shell type of polymer-supported N-heterocyclic carbene (NHC) palladium catalyst was applied to Sonogashira cross-coupling reactions without copper cocatalyst under ambient atmosphere. This supported NHC-palladium complex efficiently catalyzed the copper-free Sonogashira reaction of various aryl iodides and bromides with terminal alkynes; the reaction exhibited high dependency on the temperature and the amount of base as well as its nature. In addition, this heterogeneous catalyst exhibited good reusability for the copper-free Sonogashira reaction.     

Polystyrene-supported recyclable palladacycle catalyst for Heck, Suzuki and Sonogashira reactions

A new type of soluble polystyrene-supported palladium complex as an excellent and recyclable palladacycle catalyst was discovered for carboncarbon bond formation in Heck, Suzuki and Sonogashira reactions. Precipitation and filtration process for recycling the catalyst was also achieved.     

Porous polymer supported palladium catalyst for cross coupling reactions with high activity and recyclability

Porous polymer supported palladium catalyst for cross coupling reactions with high activity has been successfully prepared by coordination of Pd 2+ species with Schiff bases functionalized porous polymer. The catalyst has been systemically investi-gated by a series of characterizations such as TEM, N 2 adsorption, NMR, IR, XPS, etc. TEM and N 2 isotherms show that the sample maintains the nanoporous structure after the modification and coordination. XPS results show that chemical state of palladium species in the catalyst is mainly +2. More importantly, the catalyst shows very high activities and excellent recycla-bility in a series of coupling reactions including Suzuki, Sonogashira, and Heck reactions. Hot filtration and poison of catalysts experiments have also been performed and the results indicate that soluble active species (mainly Pd(0) species) in-situ gener-ated from the catalyst under the reaction conditions are the active intermediates, which would redeposit to the supporter after the reactions.     

A simple and greener approach for the synthesis of PVC supported Pd (0): application to Heck and Sonogashira reactions in water

Preparation of PVC-supported Pd nanoparticles through the reduction of PdCl₂ by a non-toxic and eco-friendly route, employing sodium formate and NaOH in ethanol–water system has been described. The prepared PVC supported Pd nanoparticles were employed as catalyst in the cross coupling reactions, that is, Heck and Sonogashira reactions in water medium to afford the respective products in good to excellent yields.     

Bis(pyrimidine)-based palladium catalysts: synthesis,X-ray structure and applications in Heck–, Suzuki–, Sonogashira–Hagihara couplings and amination reactions

The synthesis of N,N-bis(pyrimid-2-yl)amine (1), N-acetyl-N,N-bis(pyrimid-2-yl)amide (2), N-norborn-2-ene-5-ylbis(pyrimid-2-yl)carbamide (4) is described. The Pd-complex N-acetyl-N,N-bis(pyrimid-2-yl)amine palladium dichloride (3) has been prepared from compound 2 and its X-ray structure has been determined. A polymer supported catalytic system (6) was prepared via ring-opening metathesis copolymerization of 4 with 1,4,4a,5,8,8a-hexahydro-1,4,5,8-exo-endo-dimethanonaphthalene (HDMN-6) and subsequent loading with PdCl₂. Both the homogeneous and heterogeneous catalysts 3 and 6 were active in Heck–, Suzuki–, Sonogashira–Hagihara-type couplings and amination reactions using aryl iodides, bromides and chlorides.     

Synthesis of cis,cis,cis-1-alkylidene-2,3,4,5-tetrakis(diphenylphosphinomethyl)cyclopentanes

A new strategy to prepare tetradentate or pentadentate diphenylphosphine ligands has been explored from Diels-Alder adducts of fulvenes and maleic anhydride. A tetradentate phosphine ligand, bearing a side chain allowing the formation of a bond with polystyrene resin, has been prepared in seven steps from cyclopentadiene. The cis,cis,cis-1-cyclohexylidene-2,3,4,5-tetrakis(diphenylphosphinomethyl)cyclopentane (Cyclo-Tedicyp) in combination with [PdCl(C₃H₅)]₂ led to an efficient catalyst for the Heck, Suzuki and Sonogashira coupling reactions.     

An efficient copper(I) complex catalyzed Sonogashira type cross-coupling of aryl halides with terminal alkynes

A wide range of arylated alkynes are synthesized from the corresponding aryl halides and terminal alkynes through Sonogashira type cross-coupling reactions through C(aryl)-C bond formation in the presence of a catalytic amount of N,N′-dibenzyl BINAM-CuI complex under mild reaction conditions.