4482-03-5Relevant articles and documents
Two palladium-catalyzed domino reactions from one set of substrates/reagents: Efficient synthesis of substituted indenes and cis-stilbenoid hydrocarbons from the same internal alkynes and hindered Grignard reagents
Dong, Cheng-Guo,Yeung, Pik,Hu, Qiao-Sheng
, p. 363 - 366 (2007)
(Chemical Equation Presented) Two types of domino reactions from the same internal alkynes and hindered Grignard reagents based on carbopalladation, Pd-catalyzed cross-coupling reaction, and a C-H activation strategy are described. The realization of thes
A "Classical" Tetrahydroxycalix[4]arene Adopting the 1,2-Alternate Conformation
Simaan, Samah,Biali, Silvio E.
, p. 95 - 98 (2004)
The first example of a "classical" tetrahydroxycalixarene, which adopts the 1,2-alternate conformation both in solution and in the crystal, is described. Calixarene derivatives with two distal methylene groups substituted in a trans fashion by phenyl (5a)
Strategy for Selective Csp2-F and Csp2-Csp2Formations from Organoplatinum Complexes
Sarkissian, Elin,Golbon Haghighi, Mohsen
supporting information, p. 1016 - 1020 (2021/02/05)
By changing the parameters of fluorination reaction of bisaryl-platinum(II) complexes, each possible competitive pathway of Ar-Ar and Ar-F formation can be selectively controlled. It was discovered that steric hindrance, type of fluorinating reagent, and
A practical procedure for iron-catalyzed cross-coupling reactions of sterically hindered aryl-grignard reagents with primary alkyl halides
Sun, Chang-Liang,Krause, Helga,Fuerstner, Alois
, p. 1281 - 1291 (2014/05/06)
Although iron-catalyzed cross-coupling reactions of arylmagnesium halides with alkyl halides are well established and proceed effectively under a variety of experimental conditions, they often find limitations when working with sterically hindered aryl-Grignard reagents. Outlined in this paper is a practical solution that allows this gap in coverage to be filled. Specifically, it is shown that bis(diethylphosphino)ethane (depe) crafts an effective coordination environment about Fe(+2). This commercially available ligand is slim enough not to interfere with the loading of the iron center even by ortho,ortho-disubstituted arylmagnesium halides, yet capable of preventing premature reductive coupling of the resulting organoiron species, which seem to be hardly basic either. The reaction is compatible with various polar functional groups as well as with substrates containing β-heteroatom substituents. Moreover, the procedure even allows encumbered neopentylic electrophiles to be arylated with donors as bulky as mesitylmagnesium bromide, whereas secondary alkyl halides tend to eliminate.
Iron-catalyzed quick homocoupling reaction of aryl or alkynyl Grignard reagents using a phosphonium ionic liquid solvent system
Kude, Keisuke,Hayase, Shuichi,Kawatsura, Motoi,Itoh, Toshiyuki
experimental part, p. 397 - 404 (2012/01/13)
The iron-catalyzed homocoupling reaction of aryl Grignard reagent was completed very quickly when the reaction was carried out in a phosphonium salt ionic liquid solvent system at 0°C for 5 min. Using a similar reaction system, the first example of the iron-catalyzed homocoupling reaction of alkynyl Grignard reagents has also been accomplished using the ionic liquid technology.
Structure-activity relationship analysis of Pd-PEPPSI complexes in cross-couplings: A close inspection of the catalytic cycle and the precatalyst activation model
Nasielski, Joanna,Hadei, Nilofaur,Achonduh, George,Kantchev, Eric Assen B.,O'Brien, Christopher J.,Lough, Alan,Organ, Michael G.
supporting information; scheme or table, p. 10844 - 10853 (2010/12/19)
A series of Pd-N-heterocyclic carbene (Pd-NHC) complexes with various NHC, halide and pyridine ligands (PEPPSI (pyridine, enhanced, precatalyst, preparation, stabilisation and initiation) precatalysts) were prepared, and the effects of these ligands on catalyst activation and performance were studied in the Kumada-TamaoCorriu (KTC), Negishi, and Suzuki-Miyaura cross-coupling reactions. The lowered reactivity of more hindered 2,6-dimethylpyridyl complex 4 in the Negishi and KTC reactions is consistent with slow reductive dimerisation of the organometallic reaction partner during precatalyst activation. Comparative rate studies of complexes 1, 4 and 5 in the KTC and Suzuki-Miyaura reactions verify that 4 activated more slowly than the others. A potential on/ off mechanism of pyridine coordination to NHC-Pd0 is also plausible, in which the more basic pyridine stays bound for longer.
Synthesis of coordinatively unsaturated mesityliron thiolate complexes and their reactions with elemental sulfur
Hashimoto, Takayoshi,Ohki, Yasuhiro,Tatsumi, Kazuyuki
experimental part, p. 6102 - 6109 (2010/08/21)
The reactions of Fe2Mes4 (1; Mes = mesityl) with bulky thiols, namely, HSDmp (Dmp = 2,6-dimesitylphenyl), HSDxp (Dxp = 2,6-dixylylphenyl), and HSBtip [Btip = 2,6-(2,4,6-iPr 3C6H2)2C6H3], provided a series of iron(II) mesityl complexes bearing bulky thiolate ligands. These iron complexes are the thiolate-bridged dinuclear complexes Fe 2Mes2(μ-SAr)(μ-Mes) (2a, Ar = Dmp; 2b, Ar = Dxp), the 1,2-dimethoxyethane (DME) adducts (DME)Fe(SAr)(Mes) (3a, Ar = Dmp; 3b, Ar = Dxp), the mixed-valence FeI?FeII dinuclear complexes (Mes)Fe(μ-SAr)(μ-SAr)Fe (4a, Ar = Dmp; 4b, Ar = Dxp), and a low-coordinate mononuclear complex (BtipS)Fe(Mes) (5). An [Fe8S7] cluster [Fe4S3(SDmp)]2(μ-SDmp) 2(μ-SMes)(μ6-S) (6), the core structure of which is topologically relevant to that of the FeMo-cofactor of nitrogenase, was obtained from the reaction of 3a or 4a with S8. The μ-SMes ligand in 6 is formed via insertion of a sulfur atom into the Fe?C(Mes) bond. The formation of cluster 6 from 3a or 4a demonstrates that organoiron complexes are applicable as precursors for iron?sulfur clusters.
Pd-PEPPSI-IPent: Low-temperature negishi cross-coupling for the preparation of highly functionalized, tetra-ortho-substituted biaryls
Calimsiz, Selcuk,Sayah, Mahmoud,Mallik, Debasis,Organ, Michael G.
supporting information; scheme or table, p. 2014 - 2017 (2010/06/20)
(Chemical Equation Presented) Cool couplings: Complex, hindered biaryls have been prepared at temperatures ranging from 0°C to room temperature, or with gentle heating. The Pd-PEPPSI-IPent catalyst (see scheme) nicely couples starting materials containing acidic moieties and routinely prepares biaryl derivatives where one or both rings comprising the biaryl are heterocyclic. Ar1=hindered aryl or heteroaryl, Ar2=unactivated aryl or heteroaryl.
Grignard reagents in ionic solvents: Electron transfer reactions and evidence for facile Br-Mg exchange
Ramnial, Taramatee,Taylor, Stephanie A.,Clyburne, Jason A. C.,Walsby, Charles J.
, p. 2066 - 2068 (2008/02/08)
Grignard reagents form persistent solutions in phosphonium ionic liquids possessing O-donor anions and these solutions are excellent reaction media for electron transfer processes and transmetallation reactions. The Royal Society of Chemistry.
