Acyl chloride carbon insertion into dicarbaborane cages – new route to tricarbollide cages

2015 ◽  
Vol 87 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Bohumil Štíbr

AbstractReactions between the arachno-6,9-C2B8H14 dicarbaborane and acyl chlorides, RCOCl, in the presence of amine bases in CH2Cl2, followed by acidification with conc. H2SO4 at 0 °C, generate in high yields a series of neutral alkyl and aryl tricarbollides of structure 8-R-nido-7,8,9-C3B8H11 (where R=alkyls and aryls). These skeletal alkylcarbonation (SAC) reactions are consistent with an aldol-type condensation between the RCO group and open-face dicarbaborane hydrogen atoms, which is associated with the insertion of the acyl chloride RC unit into the structure under elimination of three extra hydrogen atoms as H2O and HCl. The reactions thus result in an effective cross-coupling between R and the tricarbollide cage. High-temperature reactions between 8-Ar-nido-7,8,9-C3B8H11 (where Ar=Ph, 1-C10H7, and 2-C10H7) compounds and [CpFe(CO)2]2 produced the first types of monoaryl substituted twelve-vertex ferratricarbollide complexes of general constitution [1-(CpFe)-closo-ArC3B8H10] with three different arrangements of cluster carbon vertexes. The Fe-complexation is accompanied by extensive rearrangement of the cluster carbon atoms over the twelve-vertex cage and the complexes isolated can be regarded as ferrocene analogues.

2020 ◽  
Author(s):  
Evgeny Tretyakov ◽  
Svetlana Zhivetyeva ◽  
Pavel Petunin ◽  
Dmitry Gorbunov ◽  
Nina Gritsan ◽  
...  

<p>Verdazyl-nitroxide diradicals were synthesized using the palladium-catalyzed cross-coupling reaction of the corresponding iodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex with high yields (up to 82%). The synthesized diradicals were found to be highly thermally stable and have a singlet (D<i>E</i><sub>ST</sub> » -64 cm<sup>–1</sup>) or triplet ground state (D<i>E</i><sub>ST</sub> ³ 25 and 100 cm<sup>–1</sup>), depending on which canonical hydrocarbon diradical type they belong to. Upon crystallization, triplet diradicals form unique one-dimensional (1D) spin <i>S</i> = 1 chains of organic diradicals with intrachain ferromagnetic coupling of <i>J</i>′/<i>k</i><sub>B</sub> from 3 to 6 K.</p>


2020 ◽  
Author(s):  
Chet Tyrol ◽  
Nang Yone ◽  
Connor Gallin ◽  
Jeffery Byers

By using an iron-based catalyst, access to enantioenriched 1,1-diarylakanes was enabled through an enantioselective Suzuki-Miyaura crosscoupling reaction. The combination of a chiral cyanobis(oxazoline) ligand framework and 1,3,5-trimethoxybenzene additive were essential to afford high yields and enantioselectivities in cross-coupling reactions between unactivated aryl boronic esters and a variety of benzylic chlorides, including challenging ortho-substituted benzylic chloride substrates. Mechanistic investigations implicate a stereoconvergent pathway involving carbon-centered radical intermediates.


2005 ◽  
Vol 70 (4) ◽  
pp. 430-440 ◽  
Author(s):  
Michael J. Carr ◽  
Michael G. S. Londesborough ◽  
Jonathan Bould ◽  
Ivana Císařová ◽  
Bohumil Štíbr ◽  
...  

The deprotonation of S2B17H17 with sodium hydride and subsequent reaction with [PtCl2(PMe2Ph)2] gives the new macropolyhedral metallathiaborane [(PMe2Ph)2PtS2B16H16], of which the cluster consists of a conventional eleven-vertex nido {SB10} unit, fused, with two boron atoms in common, with a {PtSB8} unit of unique ten-vertex neo-arachno constitution and geometry. The latter geometry suggests a configuration for the previously structurally uncharacterised [B10H15]- anion; starting from this configuration, DFT calculations of structure and thence of boron nuclear shieldings, which are found very closely to mimic those found experimentally, thence support a fluxional structure for [B10H15]- with three {BHB(bridging)} and two {BH(endo)} hydrogen atoms around a six-membered open face.


ChemInform ◽  
2007 ◽  
Vol 38 (11) ◽  
Author(s):  
C. Croix ◽  
A. Balland-Longeau ◽  
A. Duchene ◽  
J. Thibonnet

1983 ◽  
Vol 30 ◽  
Author(s):  
F. W. Giacobbe ◽  
D. W. Schmerling

ABSTRACTA unique and efficient plasma jet reactor has been developed and used to study the high temperature production of carbon monoxide from a reaction between powdered carbon and a pure carbon dioxide plasma. The plasma jet reactor was designed to allow the injection of powdered carbon above the arc discharge region rather than into the plasma flame below the arc discharge region. High yields of carbon monoxide, produced at relatively high efficiencies, were a direct result of this technique. The plasma jet was also designed to enable rapid changing and testing of various anode insertsAverage yields of carbon monoxide in the product gases were as high as 80–87% in selected experimental trials. Carbon monoxide was produced at rates exceeding 15,000 1/hr (at STP) with a power expenditure of 52 Kw.


2021 ◽  
Vol 43 (1) ◽  
pp. 95-95
Author(s):  
Rifhat Bibi Rifhat Bibi ◽  
Muhammad Yaseen Muhammad Yaseen ◽  
Haseen Ahmad Haseen Ahmad ◽  
Ismat Ullah Khan Ismat Ullah Khan ◽  
Shaista Parveen Shaista Parveen ◽  
...  

Transition metals mediated cross coupling methodologies provide an extremely powerful versatile pathway in organic syntheses undoubtedly, a facile route for syntheses and derivatization of biologically important heterocycles from easily available precursors. Sonogashira coupling reaction, a leading method to Csp-Csp2 bond formation is one of the most important and rapid pathways to couple aryl/vinyl halides with terminal alkynes. Current research study deals with the synthesis of alkyne substituted quinoxaline derivatives. The quinoxalines class of aromatic heterocycles exhibits a wide variety of important biological potencies. Palladium catalyzed cross coupling process provided an effective synthetic practice for the synthesis of alkyne derivatives of quinoxaline. Vareity of terminal alkynes were coupled with 2-(4-bromophenyl)quinoxaline under optimized conditions for Sonogashira reaction, affording alkyne substituted quinoxaline derivatives in high yields. The optimized reaction conditions for coupling of range of terminal alkyne with quinoxaline basic core render this process significant for designing of medicinally interesting precursors.


RSC Advances ◽  
2017 ◽  
Vol 7 (67) ◽  
pp. 42570-42578 ◽  
Author(s):  
Jiankang Miao ◽  
Bin Huang ◽  
Haiyi Liu ◽  
Mingzhong Cai

The phosphine-free, atom-efficient cross-coupling of triorganoindiums with acyl chlorides has been achieved using a recyclable MCM-41-immobilized palladium(0)–Schiff base complex.


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