- PREPARATION AND CRYSTAL STRUCTURE OF THE DICARBORANYLMAGNESIUM BIS(DIOXANE) ADDUCT Mg(2-Me-1,2-C2B10H10)2*2C4H8O2
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The preparation of Mg(2-Me-1,2-C2B10H10)2*2C4H8O2 from the carboranyl Grignard reagent RMgBr (R = the methyl-ortho-carboranyl residue, 2-Me-1,2-C2B10H10) by a dioxane-induced disproportionation reaction is described.An X-ray crystallographic study of the product has revealed a monomeric molecular structure R2MgL2 (L=1,4-dioxane, C4H8O2) in which the carboranyl groups and dioxane ligands provide the central magnesium atom with a distorted tetrahedral coordination sphere of two carbon and two oxygen atoms, with bond lengths Mg-C 2.156(5) Angstroem, Mg-O 2.038(8) Angstroem and bond angles CMgC 123.5(4) deg, OMgO 99.5(5) deg, distortions from regular tetrahedral angles attributable to the relative bulk of the carboranyl ligands.
- Clegg, William,Brown, David A.,Bryan, Stephen J.,Wade, Kenneth
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- The preparation and characterization of several meso-tetracarboranylporphyrins
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Several meso-tetracarboranylporphyrins were prepared and characterized. A Rothemund condensation designed to give a 1,2-C2B10H11 meso substituent (R) was not successful, but with R = 1-CH2-1,2-C2Bsub
- Haushalter,Butler,Rudolph
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- Rhodium-Catalyzed Regioselective Hydroxylation of Cage B?H Bonds of o-Carboranes with O2or Air
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A rhodium-catalyzed hydroxylation of a cage B4?H bond in o-carboranes with either O2or air as the oxygen source is described, and serves as a new methodology for the regioselective generation of a series of 4-OH-o-carboranes in a one-pot process. The use of either O2or air as both the oxidant and the oxygen source makes this protocol very environmentally friendly and practical.
- Lyu, Hairong,Quan, Yangjian,Xie, Zuowei
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- Transition Metal Catalyzed Direct Amination of the Cage B(4)-H Bond in o-Carboranes: Synthesis of Tertiary, Secondary, and Primary o-Carboranyl Amines
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Transition metal catalyzed regioselective amination of the cage B(4)-H bond in o-carboranes has been achieved for the first time using O-benzoyl hydroxylamines or organic azides as the amination reagents, leading to the preparation of a series of tertiary and secondary carboranyl amines. Both amination reactions proceeded under mild conditions without the addition of any external oxidants. Hydrogenolysis of the resultant product 4-N(CH2Ph)2-o-carborane afforded the primary carboranyl amine, 4-amino-o-carborane, in quantitative yield.
- Lyu, Hairong,Quan, Yangjian,Xie, Zuowei
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- Light-enabled alkenylation of iodocarboranes with unactivated alkenes
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The synthesis of alkenylated-o-carboranesviaphotoalkenylation of iodocarboranes with unactivated alkenes has been achieved. This strategy features a transition metal-free protocol, a light-promoted reaction under mild reaction conditions, broad substrate scope and good functional group tolerance. Control experiments suggest that the reaction may involve the cage C-centered radical species.
- Lu, Zhenpin,Ni, Hangcheng,Xie, Zuowei
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p. 104 - 110
(2021/12/27)
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- A facile access to mono-C-alkynylated-o-carboranes from o-carboranes and arylsulfonylacetylenes
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A facile access to mono-C-alkynyl-o-carboranes from o-carboranes and arylsulfonylacetylenes was developed. This facile process tolerates a wide variety of functional groups, occurs at mild conditions in one-pot procedure with short reaction time. The obtained mono-C-alkynyl-o-carboranes can be easily derivatized to synthesize 1,2-difunctionalized o-carboranes. This work provides a useful tool for the functionalization of o-carboranes.
- Bai, Mengyang,Duan, Zheng,Liu, Zhenxing,Tao, Guanyu,Wang, Lili
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supporting information
(2021/06/27)
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- Formal insertion of o-carborynes into ferrocenyl C-H bonds: A simple access to o-carboranylferrocenes
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Insertion of o-carborynes (1,2-dehydro-o-carboranes) into ferrocenyl C-H bonds has been described, providing a convenient methodology for the preparation of functionalized ferrocenyl o-carboranes. Reaction of the carboryne precursors 1-I-2-Li-9,12-Me2-1,2-C2B10H8 or 1-I-2-Li-3-R-1,2-C2B10H9 (R = H, Ph, Me, Cl, Br, and I) with 2.5 equiv of ferrocene at 80 °C in cyclohexane afforded [1-(η5-C5H4)(9,12-Me2-1,2-C 2B10H9)]Fe(η5-C 5H5) and [1-(η5-C5H 4)(3-R-1,2-C2B10H10)] Fe(η5-C5H5) (R = H, Ph, Me, Cl, Br, and I) in 19-44% isolated yields. On the other hand, in addition to the desired C-H bond insertion products [1-(η5-C5H4)(3-X-1, 2-C2B10H10)]Fe(η5-C 5H5), bis(ferrocenyl)-o-carboranes 1,2- [(η5-C5H5)Fe(η5-C 5H4)]2-3-X-1,2-C2B 10H9 were isolated from the reactions of 1-I-2-Li-3-X-1,2-C2B10H9 (X = Cl, Br, and I) in 12%, 15%, and 8% yields, respectively. Treatment of 1,2-dilithio-o-carborane or 1-lithio-2-methyl-o-carborane with ferrocenium hexafluorophosphate in cyclohexane also generated [1-(η5-C5H 4)(1,2-C2B10H11)] Fe(η5-C5H5) and [1-(η5- C5H4)(2-Me-1,2-C2B10H 10)]Fe(η5-C5H5) in 17% and 31% isolated yields, respectively. On the basis of these observations, it is suggested that the single-electron oxidation of ferrocene to the electrophilic ferrocenium cation by o-carborynes is crucial for the insertion reaction. Accordingly, a reaction mechanism is proposed.
- Wang, Sunewang Rixin,Xie, Zuowei
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p. 4544 - 4550
(2012/07/14)
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- Palladium/nickel-cocatalyzed cycloaddition of 1,3-dehydro-o-carborane with alkynes. Facile synthesis of C,B-substituted carboranes
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o-Carboryne (1,2-dehydro-o-carborane) has been reported as a very reactive intermediate and regarded as a three-dimensional relative of benzyne, whereas the 1,3-dehydro-o-carborane has remained elusive. In this article, we present the preparation of 1,3-dehydro-o-carborane from 3-iodo-1-lithio-o-carborane mediated by palladium(0). This reactive intermediate can be trapped by alkynes via Pd/Ni-cocatalyzed [2 + 2 + 2] cycloaddition reaction, leading to the formation of C,B-substituted-o-carborane derivatives. The possible reaction mechanism involving the formation of metal-1,3-dehydro-o-carborane followed by stepwise insertions of 2 equiv of alkyne and reductive elimination is proposed, and the relative reactivity of M-C versus M-B bond in metal-1,3-dehydro-o- carborane complexes is also discussed. This work offers a new methodology for B-functionalization of carboranes and demonstrates that metal-1,3-dehydro-o- carborane can be viewed as a new kind of boron nucleophile.
- Qiu, Zaozao,Xie, Zuowei
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p. 16085 - 16093
(2011/02/17)
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- Investigations on the reactivity of Li/Cl phosphinidenoid tungsten complexes toward various iodine compounds
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Reactivity studies of Li/Cl phosphinidenoid W(CO)5 complexes 2a,b toward various iodine compounds are reported. Transiently generated complexes 2a,b yielded no selective reactions with 3-, 9-, and 9,12-diiodo o-carbaboranes 3a-c, whereas clean transfer-io
- Streubel, Rainer,Oezbolat-Schoen, Aysel,Bode, Maren,Daniels, Joerg,Schnakenburg, Gregor,Teixidor, Francesc,Vinas, Clara,Vaca, Albert,Pepiol, Ariadna,Farras, Pau
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p. 6031 - 6035
(2010/03/04)
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- o-Carboranylcarbene and m-Carboranylcarbene
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Addition of o- and m-carboranylcarbene to olefins takes place in a largely stereospecific fashion.In the addition to cis olefins, it is the anti isomer that predominates.Insertion into carbon-hydrogen bonds occurs with a secondary/primary selectivity ratio of 3.0. (Methyl-o-carboranyl)carbene behaves like tolylcarbene in intramolecular reactions.It yields vinyl-o-carborane and the carborane analogue of benzocyclobutene. (Methyl-m-carboranyl)carbene does not give vinyl-m-carborane.
- Chari, Sarangan L.,Chiang, Sheau-Hwa,Jones, Maitland
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p. 3138 - 3145
(2007/10/02)
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- Carboranes. II. The preparation of 1- and 1,2-substituted carboranes
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The broad applicability o the conversion of mono- and disubstituted acetylenes to carboranes by treatment with decaborane and Lewis bases is demonstrated. The resultant carboranes may then be treated as typically organic, covalent products and, by usual s
- Fein, Marvin M.,Grafstein, Daniel,Paustian, John E.,Bobinski, Jack,Lichstein, Bernard M.,Mayes, Nathan,Schwartz, Nelson N.,Cohen, Murray S.
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p. 1115 - 1119
(2008/10/08)
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- Carboranes. III. Reactions of the carboranes
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The reactions of the carboranyl polyhedron and its influence on the chemistry of organofunctional substituents were investigated. Convenient laboratory syntheses for carborane, 1-methylcarborane, and some functional derivatives were developed. An unusual rearrangement in a Grignard reagent was observed. Metalation, animation, solvolytic degradation, and other reactions of these novel compounds were studied.
- Grafstein, Daniel,Bobinski, Jack,Dvorak, Joseph,Smith, Harry,Schwartz, Nelson,Cohen, Murray S.,Fein, Marvin M.
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p. 1120 - 1125
(2008/10/08)
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- A new series of organoboranes. III. Some reactions of 1,2-dicarbaclovododecaborane(12) and its derivatives
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The general participation of carborane and its derivatives in standard organic chemical transformations has been established. Reactions of carborane and some functionally substituted derivatives are described. Differences in the reactivity of the hydrogen atoms attached to carbon atoms of carborane from those attached to the boron atoms have been demonstrated.
- Heying,Ager Jr.,Clark,Alexander,Papetti,Reid,Trotz
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p. 1097 - 1105
(2008/10/08)
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