- Photoredox/Nickel Dual Catalysis for the C(sp3)–C(sp3) Cross-Coupling of Alkylsilicates with Alkyl Halides
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Alkylsilicates were engaged under photoredox/nickel dual catalysis conditions with alkyl halides for the first time. The C(sp3)–C(sp3) cross-coupling products were obtained in moderate yields and were accompanied by the homocoupling
- Lévêque, Christophe,Corcé, Vincent,Chenneberg, Ludwig,Ollivier, Cyril,Fensterbank, Louis
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supporting information
p. 2118 - 2121
(2017/04/24)
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- RECYCLING OF ORGANOTIN COMPOUNDS
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A method for the synthesis of a first organic molecule, said method comprising the steps of: a) Reacting a first reactant with an organotin reactant having at least one optionally substituted organic group having from 5 to 20 carbon atoms selected from alkyl, alkenyl, alkynyl, alkoxyalkyl, alkoxy, alkylthioalkyl, carboxylates and alkylaminoalkyl groups, thereby forming a mixture of a product and a tin-containing by-product, and b) Removing most of the tin-containing by-product from said mixture in such a way as to provide a purified product comprising less than 1000 ppm of remaining tin-containing by- product, wherein said step of removing most of said tin-containing by-product is either an extraction between a first liquid and a second liquid, said second liquid being more polar than said first liquid and at least partly immiscible therewith or is a reversed phase chromatography.
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Page/Page column 44
(2013/12/03)
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- Preparation, structure, and reactivity of nonstabilized organoiron compounds. Implications for iron-catalyzed cross coupling reactions
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A series of unprecedented organoiron complexes of the formal oxidation states -2, 0, +1, +2, and +3 is presented, which are largely devoid of stabilizing ligands and, in part, also electronically unsaturated (14-, 16-, 17- and 18-electron counts). Specifically, it is shown that nucleophiles unable to undergo β-hydride elimination, such as MeLi, PhLi, or PhMgBr, rapidly reduce Fe(3+) to Fe(2+) and then exhaustively alkylate the metal center. The resulting homoleptic organoferrate complexes [(Me4Fe)(MeLi)] [Li(OEt2)]2 (3) and [Ph4Fe][Li(Et 2O)2][Li(1,4-dioxane)] (5) could be characterized by X-ray crystal structure analysis. However, these exceptionally sensitive compounds turned out to be only moderately nucleophilic, transferring their organic ligands to activated electrophiles only, while being unable to alkylate (hetero)aryl halides unless they are very electron deficient. In striking contrast, Grignard reagents bearing alkyl residues amenable to β-hydride elimination reduce FeXn (n = 2, 3) to clusters of the formal composition [Fe(MgX)2]n. The behavior of these intermetallic species can be emulated by structurally well-defined lithium ferrate complexes of the type [Fe(C2H4) 4][Li(tmeda)]2 (8), [Fe(cod)2][Li(dme)] 2 (9), [CpFe(C2H4)2][Li(tmeda)] (7), [CpFe(cod)][Li(dme)] (11), or [Cp*Fe(C2H4) 2][Li(tmeda)] (14). Such electron-rich complexes, which are distinguished by short intermetallic Fe-Li bonds, were shown to react with aryl chlorides and allyl halides; the structures and reactivity patterns of the resulting organoiron compounds provide first insights into the elementary steps of low valent iron-catalyzed cross coupling reactions of aryl, alkyl, allyl, benzyl, and propargyl halides with organomagnesium reagents. However, the acquired data suggest that such C-C bond formations can occur, a priori, along different catalytic cycles shuttling between metal centers of the formal oxidation states Fe(+1)/Fe(+3), Fe(0)/Fe(+2), and Fe(-2)/Fe(0). Since these different manifolds are likely interconnected, an unambiguous decision as to which redox cycle dominates in solution remains difficult, even though iron complexes of the lowest accessible formal oxidation states promote the reactions most effectively.
- Fuerstner, Alois,Martin, Ruben,Krause, Helga,Seidel, Guenter,Goddard, Richard,Lehmann, Christian W.
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p. 8773 - 8787
(2008/12/23)
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- Synthesis of long chain ω-aralkylbromides
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1-Iodo-4-acetoxybutane is a useful 4 carbon synthon which reacts selectively with Grignards under copper catalysis. The immediate products are converted to bromides.
- Forth,Smith
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p. 951 - 959
(2007/10/02)
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