16390-61-7Relevant academic research and scientific papers
1-Phenyl-1,2-dicarba-closo-dodecaborane, 1-Ph-1,2-closo-C2B10H11. Synthesis, Characterization, and Structure As Determined in the Gas Phase by Electron Diffraction, in the Crystalline Phase at 199 K by X-ray Diffraction, and by ab Initio Computations
Brain, Paul T.,Cowie, Jill,Donohoe, David J.,Hnyk, Drahomír,Rankin, David W.H.,Reed, David,Reid, Bruce D.,Robertson, Heather E.,Welch, Alan J.,Hofmann, Matthias,Von Schleyer, Paul Ragué
, p. 1701 - 1708 (1996)
The compound 1-phenyl-1,2-dicarba-closo-dodecaborane(12), 1-C6H5-1,2-closo-C2B10H11 (1), has been synthesized and characterized by a complete assignment of its 11B NMR spectrum via 11B{1H}/11B{1H} (COSY), 1H{11Bselective} and 1H{11B}/1H{11B} (COSY) spectroscopy. An electron- and X-ray diffraction investigation of 1, complemented by ab initio calculations, has been undertaken. The gas-phase electron-diffraction (GED) data can be fitted by several models describing conformations which differ in the position of the phenyl ring with respect to the carborane cage. Local symmetries of C2v and D6h for the 1,2-C2B10 and C6 moieties, respectively, were adopted in the GED model in order to simplify the problem. In addition, constraints among the close-lying C-C and B-B bonds were employed. However, even though such simplifications led to satisfactory refinements (RG = 0.069- 0.071), a unique, definitive solution could not be gained. The (C-C)mean, (C-B)mean and (B-B)mean bond lengths, ra, are ca. 1.44, 1.72, and 1.78 ?, respectively. The C6 hexagon, with ra(C-C) = ca. 1.394 ?, either eclipses the C(1)-C(2) vector (overall Cs symmetry) or more or less eclipses the C(1)-B(4) cluster bond (overall C1 symmetry). In contrast, in the solid at 199 K, the ring lies at a position intermediate between the two GED positions, as determined by X-ray crystallography [C8H16B10, monoclinic P21/a: a = 12.047(3) ?, b = 18.627(4) ?, c = 12.332(5) ?, β = 110.09(4)°, Z = 8]. The C-B distances span the range 1.681(6)-1.743(5) ?, and B-B lengths lie between 1.756(6) and 1.795(6) ?. A similar conformation was found for the theoretical (RHF/6-31G* level) structure which was fully optimized in C1 symmetry. The re distances are consistent with the dimensions derived in the experimental studies. IGLO calculations of the 11B chemical shifts, in addition to SCF single-point energies of the GED structures, further support these observations.
Light-promoted copper-catalyzed cage C-Arylation of: O-carboranes: facile synthesis of 1-Aryl-o-carboranes and o-carborane-fused cyclics
Lu, Zhenpin,Ni, Hangcheng,Xie, Zuowei
supporting information, p. 14944 - 14948 (2021/09/04)
Light-promoted, copper catalyzed cage C-H arylation of o-carboranes with aryl halides has been achieved, leading to the facile synthesis of a variety of 1-Aryl-o-carboranes and o-carborane-fused cyclics. This method has the following features: (1) using o
Phosphine oxide-directed palladium-catalyzed B(3)–H arylation of o-carboranes
Lian, Lingxiang,Lin, Caixia,Yu, Yi,Yuan, Yaofeng,Ye, Ke-Yin
supporting information, (2020/11/25)
The selective functionalization of carboranes has received increasing research interests due to their wild applications in chemistry, life, and material sciences. Among various structurally diverse carboranes, the development of selective functionalization of the commercially available o-carborane (1,2-C2B10H12) has largely focused on the two acidic C[sbnd]H bonds. By contrast, research on the activation of the other ten hydridic cage B–H vertices is relatively less explored. Of particularly challenging, the most electron-deficient nature of B(3,6)-H bonds render very few synthetic methods available for their functionalization. Herein, we develop a phosphine oxide-directed palladium-catalyzed highly B(3)–H selective arylation of o-carboranes under very mild reaction conditions in short reaction time.
Photoarylation of Iodocarboranes with Unactivated (Hetero)Arenes: Facile Synthesis of 1,2-[(Hetero)Aryl]n-o-Carboranes (n=1,2) and o-Carborane-Fused Cyclics
Ni, Hangcheng,Qiu, Zaozao,Xie, Zuowei
supporting information, p. 712 - 716 (2017/01/14)
Photoarylation of iodocarboranes with unactivated arenes/heteroarenes at room temperature has been achieved, for the first time, thus leading to the facile synthesis of a large variety of cage carbon mono(hetero)arylated and di(hetero)arylated o-carboranes. This work represents a clean, efficient, transition-metal-free, and cheap synthesis of functionalized carboranes, which has significant advantages over the known methods.
Palladium-Catalyzed Direct Cross-Coupling of Carboranyllithium with (Hetero)Aryl Halides
Lu, Ju-You,Wan, Hong,Zhang, Jianwei,Wang, Zhixuan,Li, Yang,Du, Yongmei,Li, Chunying,Liu, Zhao-Tie,Liu, Zhong-Wen,Lu, Jian
supporting information, p. 17542 - 17546 (2016/11/28)
A palladium-catalyzed direct C-arylation reaction of readily available cage carboranyllithium reagents with aryl halides has been developed for the first time. This method is applicable to a wide range of aryl halide substrates including aryl iodides, aryl bromides, and heteroaromatic halides.
Syntheses and reductions of C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes
Kahlert, Jan,B?hling, Lena,Brockhinke, Andreas,Stammler, Hans-Georg,Neumann, Beate,Rendina, Louis M.,Low, Paul J.,Weber, Lothar,Fox, Mark A.
, p. 9766 - 9781 (2015/06/08)
Two C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes, 1-(BMes2)-2-R-1,2-C2B10H10 (1, R = H, 2, R = Ph), were synthesised by lithiation of 1,2-dicarba-closo-dodecaborane and 1-phenyl-1,2-dicarba-closo-dodecaborane, respectively, with n-butyllithium and subsequent reaction with fluorodimesitylborane. These novel compounds were structurally characterised by X-ray crystallography. Compounds 1 and 2 are hydrolysed on prolonged exposure to air to give mesitylene and boronic acids 1-(B(OH)2)-2-R-1,2-C2B10H10 (3, R = H, 4, R = Ph respectively). Addition of fluoride anions to 1 and 2 resulted in boryl-carborane bond cleavage to give dimesitylborinic acid HOBMes2. UV absorption bands at 318-333 nm were observed for 1 and 2 corresponding to local π-π-transitions within the dimesitylboryl groups while visible emissions at 541-664 nm with Stokes shifts of 11 920-16 170 cm-1 were attributed to intramolecular charge transfer transitions between the mesityl and cluster groups. Compound 2 was shown by cyclic voltammetry to form a stable dianion on reduction. NMR spectra for the dianion [2]2- were recorded from solutions generated by reductions of 2 with alkali metals and compared with NMR spectra from reductions of 1,2-diphenyl-ortho-carborane 5. On the basis of observed and computed 11B NMR shifts, these nido-dianions contain bowl-shaped cluster geometries. The carborane is viewed as the electron-acceptor and the mesityl group is the electron-donor in C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes.
Straightforward synthesis of radioiodinated Cc-substituted o-carboranes: Towards a versatile platform to enable the in vivo assessment of BNCT drug candidates
Gona,Thota,Baz,Gómez-Vallejo,Llop
, p. 9915 - 9920 (2015/06/08)
Due to their high boron content and rich chemistry, dicarba-closo-dodecaboranes (carboranes) are promising building blocks for the development of drug candidates with application in Boron Neutron Capture Therapy. However, the non-invasive determination of their pharmacokinetic properties to predict therapeutic efficacy is still a challenge. Herein, we have reported the unprecedented preparation of mono-[125I] iodinated decaborane via a catalyst-assisted isotopic exchange. Subsequent reactions of the radiolabelled species with acetylenes in acetonitrile under microwave heating yield the corresponding 125I-labelled, Cc-substituted o-carboranes with good overall radiochemical yields in short reaction times. The same synthetic strategy was successfully applied to the preparation of 131I-labelled analogues, and further extension to other radioisotopes of iodine such as 124I (positron emitter) or 123I (gamma emitter) can be envisaged. Hence, the general strategy reported here is suitable for the preparation of a wide range of radiolabelled Cc-substituted o-carborane derivatives. The labelled compounds might be subsequently investigated in vivo by using nuclear imaging techniques such as Single Photon Emission Computerized Tomography or Positron Emission Tomography.
Nickel-catalyzed cross-coupling reactions of o-carboranyl with aryl iodides: Facile synthesis of 1-aryl-o-carboranes and 1,2-diaryl-o-carboranes
Tang, Cen,Xie, Zuowei
supporting information, p. 7662 - 7665 (2015/06/25)
A nickel-catalyzed arylation at the carbon center of o-carborane cages has been developed, thus leading to the preparation of a series of 1-aryl-o-carboranes and 1,2-diaryl-o-carboranes in high yields upon isolation. This method represents the first examp
High yielding synthesis of carboranes under mild reaction conditions using a homogeneous silver(I) catalyst: Direct evidence of a bimetallic intermediate
El-Zaria, Mohamed E.,Keskar, Kunal,Genady, Afaf R.,Ioppolo, Joseph A.,McNulty, James,Valliant, John F.
supporting information, p. 5156 - 5160 (2014/05/20)
Methods used to prepare functionalized carboranes generally require heating to high temperatures, and thus limits the range of derivatives which can be prepared directly from alkynes. We show here that by using a homogeneous silver(I) catalyst it is now possible to prepare carboranes in good to excellent yield at temperatures below 40 °C, including at room temperature. The process is general and provides an important new synthetic strategy for the preparation of functionalized boron clusters. Cluster around: Current methods to prepare carboranes require heating to high temperatures, thereby limiting the range of derivatives which can be prepared from functionalized alkynes. By using a AgI catalyst it is possible to prepare carboranes from substituted alkynes in good to excellent yields at temperatures below 40 °C, including room temperature. The approach provides an important new synthetic strategy for the preparation of functionalized boron clusters.
High yielding preparation of dicarba-closo-dodecaboranes using a silver(I) mediated dehydrogenative alkyne-insertion reaction
Toppino, Antonio,Genady, Afaf R.,El-Zaria, Mohamed E.,Reeve, James,Mostofian, Fargol,Kent, Jeff,Valliant, John F.
supporting information, p. 8743 - 8749 (2013/09/02)
The synthesis of 1,2-dicarba-closo-dodecaboranes (ortho-carboranes) is often low yielding which is a critical issue given the increasing use of boron clusters in material science and medicinal chemistry. To address this barrier, a series of Cu, Ag, and Au salts were screened to identify compounds that would enhance the yields of ortho-caboranes produced when treating alkynes with B 10H12(CH3CN)2. Using a variety of functionalized ligands including mono- and polyfunctional internal and terminal alkynes, significant increases in yield were observed when AgNO3 was used in catalytic amounts. AgNO3 appears to prevent unwanted reduction/hydroboration of the alkyne prior to carborane formation, and the process is compatible with aryl, halo, hydroxy, nitrile, carbamate, and carbonyl functionalized alkynes.
