- Easily Prepared Mono(N,N-dialkylamino)phosphine Palladium(II) Complexes: Structural and Catalytic Evaluation
-
The search for efficient, active and universal catalyst systems for transition-metal catalyzed cross-coupling reactions, continues to be of interest to researchers world-wide. Herein, we report two new Pd(II) complexes, effortlessly prepared from N,N-dialkylamino-phosphines for Suzuki-Miyaura cross-coupling reactions. These sufficiently hindered (% VBur=30.0–31.5 %) and electron rich (vCO=1947.41–1946.29 cm?1) aminophosphines formed active catalysts for Suzuki-Miyaura coupling of aryl bromides and chlorides.
- Adeyinka, Adedapo S.,Holzapfel, Cedric W.,Lamola, Jairus L.,Maumela, Munaka C.,Mmutlane, Edwin M.,Ngodwana, Lonwabo,Shilubana, Joy C.,Vatsha, Banele
-
supporting information
p. 2578 - 2582
(2021/07/06)
-
- A Spiroalkylation Method for the Stereoselective Construction of α-Quaternary Carbons and Its Application to the Total Synthesis of (R)-Puraquinonic Acid
-
Cyclic α-quaternary carbon stereocenters were prepared from biselectrophillic substrates and an easily prepared chiral bicyclic sulfonyl lactam. This was achieved in two steps by spiroalkylation, employing biphasic reaction conditions with a phase-transfer catalyst, followed by reduction and alkylation with a series of alkyl halide electrophiles. The products of this method were isolated in good yields with with high levels of diastereoselectivity. This methodology was employed in the enantioselective total synthesis of (R)-puraquinonic acid (1) for a late-stage installation of the α-quaternary carbon stereocenter. This enabled the shortest synthesis of 1 to date, an eight-pot sequence providing an overall yield of 14%.
- Elmehriki, Adam A. H.,Gleason, James L.
-
supporting information
p. 9729 - 9733
(2019/12/02)
-
- The imidazo{[4,5-f][1,10]-phenanthrolin}l-2-ylidene and its palladium complexes: Synthesis, characterization, and application in C-C cross-coupling reactions
-
1,3-dibutyl-1H-imidazo[4,5-f][1,10]phenanthrolinium iodide, L5.2HI ligand and their mono-, di-, tri-, tetra-nuclear palladium(II) complexes (5.HPF6, 6–8) were synthesized and characterized by elemental analysis, FTIR, UV–visible and
- G?k, Lütfiye,Günnaz, Salih,?ahin, Zarife Sibel,Pelit, Levent,Türkmen, Hayati
-
-
- Gold(i)-catalyzed dehydrogenative cycloisomerization of 1,5-enynes
-
The gold(i)-catalyzed dehydrogenative cycloisomerization of cyclopropane-tethered 1,5-enynes proceeded smoothly to give multisubstituted benzene derivatives in good to excellent yields. Synthetically important benzocyclobutenes can be produced in high yields in the presence of a gold(i) catalyst and DDQ. Furthermore, this reaction also works very well for non-cyclopropane tethered 1,5-enynes.
- Chen, Gen-Qiang,Fang, Wei,Wei, Yin,Tang, Xiang-Ying,Shi, Min
-
supporting information
p. 10799 - 10802
(2016/09/07)
-
- A 2-methyl-3-phenyl-methanol preparation method
-
The invention relates to a preparation method of 2-methyl-3-phenyl benzyl alcohol. The preparation method comprises the steps of (1) under a lighting condition, enabling 2,3-dimethyl biphenyl to mix and react with chlorine gas at 40-120 DEGC; or, in the presence of an initiator, enabling the 2,3-dimethyl biphenyl to react with sulfuryl chloride or chlorine gas at 40-120 DEG C; (2) implementing an esterification reaction on 2-methyl-3-chloromethyl biphenyl prepared by the step (1) and an esterification reagent in a solvent in the presence of a catalyst; and (3) under an alkaline condition, hydrolyzing an esterification product prepared by the step (2), and controlling pH range within 9-14. The preparation method disclosed by the invention is simple and convenient to operate, relatively low in cost, not high in requirement on equipment and applicable to industrial production. (img file='DDA0000466672690000011. TIF'wi='1528'he='344'/).
- -
-
Paragraph 0070; 0071
(2016/10/08)
-
- A General Palladium-Catalyzed Hiyama Cross-Coupling Reaction of Aryl and Heteroaryl Chlorides
-
A general palladium-catalyzed Hiyama cross-coupling reaction of aryl and heteroaryl chlorides with aryl and heteroaryl trialkoxysilanes by a Pd(OAc)2/L2 catalytic system is presented. A newly developed water addition protocol can dramatically improve the product yields. The conjugation of the Pd/L2 system and the water addition protocol can efficiently catalyze a broad range of electron-rich, -neutral, -deficient, and sterically hindered aryl chlorides and heteroaryl chlorides with excellent yields within three hours and the catalyst loading can be down to 0.05 mol % Pd for the first time. Hiyama coupling of heteroaryl chlorides with heteroaryl silanes is also reported for the first time. The reaction can be easily scaled up 200 times (100 mmol) without any degasification and purification of reactants; this facilitates the practical application in routine synthesis.
- Yuen, On Ying,So, Chau Ming,Man, Ho Wing,Kwong, Fuk Yee
-
supporting information
p. 6471 - 6476
(2016/05/09)
-
- Development of Structurally Diverse N-Heterocyclic Carbene Ligands via Palladium-Copper-Catalyzed Decarboxylative Arylation of Pyrazolo[1,5-a]pyridine-3-carboxylic Acid
-
A series of fused non-classical normal N-heterocyclic carbenes, Pyrpy-NHC precursors derived from pyrazolo[1,5-a]pyridines, has been prepared using palladium-copper-catalyzed decarboxylative arylation of pyrazolo[1,5-a]pyridine-3-carboxylic acid. Air-stable palladium and rhodium complexes of these ligands have been synthesized via mild transmetallation of Ag-Pyrpy-NHC. The structural properties of Rh(Pyrpy-NHC)(COD)Cl complexes were determined via X-ray analysis. The measurement of the CO stretching frequencies of dicarbonyl Rh-Pyrpy-NHC complexes revealed that the electron donating strength of Pyrpy-NHC could be tuned by varying the substituents of the aryl group. A catalytic study of the Pd-Pyrpy-NHC complexes revealed promising activity in the Suzuki–Miyaura reaction under ambient atmospheric conditions. (Figure presented.).
- Alam, Khyarul,Kim, Seong Min,Kim, Do Joong,Park, Jin Kyoon
-
p. 2661 - 2670
(2016/08/31)
-
- PtI2-catalyzed cyclization of 3-acyloxy-1,5-enynes with the elimination of HOAc and a benzyl shift: Synthesis of unsymmetrical m-terphenyls
-
A novel cyclization of 3-acyloxy-1,5-enynes is developed in the presence of PtI2 for the synthesis of substituted unsymmetrical m-terphenyls in good to excellent yields. Two unique steps are involved in this transformation, which includes the elimination of HOAc and benzyl group migration. DFT calculations indicated that the rate-determining step is the migration of the benzylic carbocation to form a zwitterionic intermediate followed by the elimination of HOAc. The subsequent cyclopropanation of the zwitterionic intermediate is the regioselectivity-determining step.
- Huang, Kaimeng,Ke, Xiaona,Wang, Hongkai,Wang, Junying,Zhou, Chenchen,Xu, Xiufang,Liu, Lingyan,Li, Jing
-
p. 4486 - 4493
(2015/04/14)
-
- Direct catalytic cross-coupling of organolithium compounds
-
Catalytic carbon-carbon bond formation based on cross-coupling reactions plays a central role in the production of natural products, pharmaceuticals, agrochemicals and organic materials. Coupling reactions of a variety of organometallic reagents and organic halides have changed the face of modern synthetic chemistry. However, the high reactivity and poor selectivity of common organolithium reagents have largely prohibited their use as a viable partner in direct catalytic cross-coupling. Here we report that in the presence of a Pd-phosphine catalyst, a wide range of alkyl-, aryl- and heteroaryl-lithium reagents undergo selective cross-coupling with aryl- and alkenyl-bromides. The process proceeds quickly under mild conditions (room temperature) and avoids the notorious lithium halogen exchange and homocoupling. The preparation of key alkyl-, aryl- and heterobiaryl intermediates reported here highlights the potential of these cross-coupling reactions for medicinal chemistry and material science.
- Giannerini, Massimo,Fananas-Mastral, Martin,Feringa, Ben L.
-
p. 667 - 672
(2013/08/23)
-
- Palladium-catalyzed arylation of simple arenes with iodonium salts
-
The development of an arylation protocol for simple arenes with diaryliodonium salts using the Herrmann-Beller palladacycle catalyst is reported. The reaction takes simple aromatic feedstocks and creates valuable biaryls for use in all sectors of the chem
- Storr, Thomas E.,Greaney, Michael F.
-
supporting information
p. 1410 - 1413
(2013/05/09)
-
- Pd complexes based on phosphine-linked cyclophosphazenes: Synthesis, characterization and application in suzuki coupling reactions
-
Palladium complexes were obtained by reaction of phosphine-linked cyclophosphazenes, (P3N3)(O-C6H 4-PR2)6, where R = phenyl, i-propyl or cyclohexyl, with using a Pd/ligand molar ratio of 3/1. The (P3N 3)(O-C6H4-PR2)6Pd 3(dba)x complexes were characterized by elemental analyses, mass spectrometry, 31P NMR and FT-IR where a characteristic nC=C band of dba coordinated to palladium was always observed. All complexes were tested in Suzuki coupling reactions between phenylboronic acid and aryl halides. Turnover numbers as high as ca. 17,500 for the coupling of 2-bromotoluene with chlorophenylboronic acid could be obtained for R = cyclohexyl. The complex based on -PPh2 was also immobilized in silica matrixes by the sol-gel method. Preliminary experiments showed that the immobilized catalyst could be used in at least three consecutive Suzuki reactions with the same catalytic activity.
- De Paula, Vanderlei I.,Sato, Cintia A.,Buffon, Regina
-
scheme or table
p. 258 - 266
(2012/05/05)
-
- Iron-mediated direct arylation of unactivated arenes
-
(Chemical Equation Presented) Inexpensive and straightforward: An iron-mediated cross-coupling reaction generates biaryl compounds through C-H bond activation, using easily handled reagents with low toxicity. Under the optimized reaction conditions a series of substituted phenylboronic acids were coupled with several simple unactivated arenes.
- Wen, Jun,Zhang, Ji,Chen, Shan-Yong,Li, Jing,Yu, Xiao-Qi
-
supporting information; experimental part
p. 8897 - 8900
(2009/05/26)
-
- Direct C-H bond arylation of arenes with aryltin reagents catalysed by palladium complexes
-
Direct C-H bond arylation of simple arenes with aryltin reagents has been successfully catalysed by PdCl2 in the presence of CuCl2. CuCl2 proved to be an activator for a palladium intermediate as well as an oxidant. The Royal Society of Chemistry.
- Kawai, Hiroshi,Kobayashi, Yasuhiro,Oi, Shuichi,Inoue, Yoshio
-
p. 1464 - 1466
(2008/12/21)
-
- Palladium-catalyzed Suzuki-Miyaura cross-coupling of various aryl halides using ortho-alkyl-substituted arylphosphanes and (ortho-alkylphenyl)- alkylphosphanes under microwave heating
-
Mono- and dinuclear palladium(II) chloride complexes of various ortho-alkyl-substituted aryl- and alkylphosphanes were prepared. Subsequently, these were characterized by 1H NMR and 31P{1H} NMR spectroscopy, X-ray crystallographic studies and mass spectroscopy. The palladium complexes were screened as potential catalysts for the microwave-assisted Suzuki-Miyaura coupling reaction of several aryl halides under aerobic conditions. A preliminary study showed that excellent results can be obtained even for electron-rich bromides and unactivated aryl chlorides with an optimized solvent, base and catalyst loading using specific phosphane ligands. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Vuoti, Sauli,Autio, Juho,Laitila, Minna,Haukka, Matti,Pursiainen, Jouni
-
p. 397 - 407
(2008/09/17)
-
- Palladium-catalyzed Suzuki-Miyaura cross-couplings of aryl tosylates with potassium aryltrifluoroborates
-
(Chemical Equation Presented) Pd-catalyzed Suzuki-Miyaura cross-coupling reaction of aryl tosylates with potassium aryl trifluoroborate in the presence of bulky and electron-rich phosphine ligand is described. In addition, a useful chemoselective coupling of an aryl chloride in the presence of a tosyloxy group was demonstrated.
- Zhang, Liang,Meng, Tianhao,Wu, Jie
-
p. 9346 - 9349
(2008/03/12)
-
- Pd(ii) complexes of N,S-heterocyclic carbenes with pendant and coordinated allyl function and their Suzuki coupling activities
-
3-(2-Propenyl)benzothiazolium bromide (A) provides a direct and simple entry to Pd(ii) complexes with N,S-heterocyclic carbene (NSHC) ligands functionalized with an allyl pendant with hemilabile potential. Addition of salt A to Pd(OAc)2 eliminates HOAc and affords the bis(carbene) complexes cis-[PdBr2(NHSC)2] (cis-1, NSHC = 3-(2-propenyl) benzothiazolin-2-ylidene) and trans-[PdBr2(NHSC)2] (trans-1) along with the monocarbene complexes [PdBr2(NSHC)] (2) and trans-[PdBr2(benzothiazole-κN)(NSHC)] (3) as minor side products. Salt-metathesis of cis-1 with AgO2CCF3 yields the mixed dicarboxylato-bis(carbene) complex cis-[Pd(O2CCF 3)2(NSHC)2] (4). Complexes cis-1, trans-1 and 4 were characterized by multinuclear NMR spectroscopies, ESI mass spectrometry and elemental analysis. The molecular structures of complexes cis-1, 2 and 3 have been determined by X-ray single crystal diffraction. Complexes cis-1 and 4 as well as an in situ mixture of Pd(OAc)2 and salt A are active toward Suzuki-Miyaura coupling of aryl bromides and activated aryl chlorides giving good conversions. The Royal Society of Chemistry.
- Yen, Swee Kuan,Koh, Lip Lin,Huynh, Han Vinh,Hor, T. S. Andy
-
p. 3952 - 3958
(2008/02/12)
-
- Suzuki and Heck coupling reactions mediated by palladium complexes bearing trans-spanning diphosphines
-
Palladium complexes of three trans-spanning diphosphines are examined for effecting C-C coupling reactions. Ten aryl halides of varying electron density were screened in Suzuki coupling reactions with phenylboronic acid and in Heck reactions with styrene.
- Smith, Rhett C.,Bodner, Christina R.,Earl, Meredith J.,Sears, Nathaniel C.,Hill, Nicholas E.,Bishop, Lee M.,Sizemore, Nicholas,Hehemann, Dave T.,Bohn, Justin J.,Protasiewicz, John D.
-
p. 477 - 481
(2007/10/03)
-
- Catalytic system and method for coupling of aromatic compounds
-
A catalytic process for production of biphenyl and its derivatives by coupling of substituted or unsubstituted monoaryl compounds in the presence of a catalytic system comprising at least one Pd (II) compound and a strong acid or a mixture of acids. The process provides high conversions and high selectivity under mild temperature conditions and short reaction times. The strong acid or mixture of acids has a Hammett acidity of less than about -10, and contains a predominant amount of counterions which form a weak ligand complex with palladium (II). The method is highly selective to formation of desired biaryl isomers, such as 4,4'-isomers, and allows control of the relative amounts of isomers of biaryl compounds and substituted monoaryl compounds in the final product.
- -
-
-
- Aromatic hydrocarbons in the gaseous and condensed phase. A nuclear decay study
-
A nuclear technique based on the spontaneous decay of tritiated precursors has been used in a comparative stydy of aromatic phenylation by free phenylinium ions, both in the gas and liquid phase.The mechanism of the major competitive processes promoted by phenylinium ion attack, are discussed.
- Angelini, Giancarlo,Keheyan, Yeghis,Speranza, Maurizio
-
p. 367 - 370
(2007/10/02)
-