Kinetics of ortho-carborane formation revisited

Islam, Saiful; Johnson, Frederic A.; Hill, W. E.; SILVA-TRIVINO, L. M.

doi:10.1016/s0020-1693(96)05544-2

Cited by 7 publications

(3 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is perhaps surprising that only one product was observed in each of the reactions of 6 with a terminal alkyne. On the basis of the previously proposed pathway for alkyne insertion, two different isomers, 1-R-4-X-1,2-C 2 B 10 H 10 and 2-R-4-X-1,2-C 2 B 10 H 10 , should be possible depending upon the alkyne orientation during insertion (Figure ). However, in all cases, both the NMR data and TLC analyses of the reactions with 6 indicated only one product was formed.…”

Section: Resultsmentioning

confidence: 94%

“…Dissociation of one Me 2 S from this adduct then enables alkyne association to form a 6-(RCCH)-9-(Me 2 S)-B 10 H 12 intermediate. The loss of the second dimethylsulfide and H 2 allows alkyne insertion into the open face of the decaborane cage to form the ortho -carborane structure . The report that acetylene insertion into arachno -2-Br-6,9-(Et 2 S) 2 -B 10 H 11 produced a mixture of B-bromonated C 2 B 10 -carboranes suggested that 6 could be employed as a precursor to B-triflated ortho -carboranes.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, Structural Characterization, and Reactivity Studies of 5-CF₃SO₃-B₁₀H₁₃

et al. 2014

View full text Add to dashboard Cite

In contrast to previous reactions carried out in cyclopentane solvent at room temperature that produced 6-TfO-B10H13 (TfO = CF3SO3), the reaction of closo-B10H10(2-) with a large excess of trifluoromethanesulfonic acid in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate (bmimOTf) gave exclusively the previously unknown 5-TfO-B10H13 isomer. Experimental and computational studies demonstrated that the difference in the products of the two reactions is a result of 6-TfO-B10H13 isomerizing to 5-TfO-B10H13 above room temperature in bmimOTf solutions. Reactivity studies showed that 5-TfO-B10H13: (1) is deprotonated by reaction with 1,8-bis(dimethylamino)naphthalene to form the 5-TfO-B10H12(1-) anion; (2) reacts with alcohols to produce 6-RO-B10H13 boryl ethers (R = Me and 4-CH3O-C6H4); (3) undergoes olefin-hydroboration reactions to form 5-TfO-6,9-R2-B10H11 derivatives; and (4) forms a 5-TfO-6,9-(Me2S)2-B10H11 adduct at its Lewis acidic 6,9-borons upon reaction with dimethylsulfide. The 5-TfO-6,9-(Me2S)2-B10H11 adduct was also found to undergo alkyne-insertion reactions to form a range of previously unreported triflate-substituted 4-TfO-ortho-carboranes (1-R-4-TfO-1,2-C2B10H10) and reactions with triethylamine or ammonia to form the first TfO-substituted decaborate [R3NH(+)]2[2-TfO-B10H9(2-)], and [R3NH(+)]2[1-TfO-B10H9(2-)] (R = H, Et) salts.

show abstract

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Synthesis, Structural Characterization, and Reactivity Studies of 5-CF₃SO₃-B₁₀H₁₃

et al. 2014

View full text Add to dashboard Cite

show abstract

“…It has been reported that the yields of carboranes from less basic acetylenes such as propargyl bromide are generally greater than those from more basic acetylenes . This is somewhat counterintuitive since less basic acetylenes introduce higher activation enthalpies.…”

Section: Introductionmentioning

confidence: 99%

High Yielding Preparation of Dicarba-closo-dodecaboranes Using a Silver(I) Mediated Dehydrogenative Alkyne-Insertion Reaction

et al. 2013

View full text Add to dashboard Cite

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 B10H12(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.

show abstract

Polyhedral Carboranes

Fox

2007

Comprehensive Organometallic Chemistry III

View full text Add to dashboard Cite

Kinetics of ortho-carborane formation revisited

Cited by 7 publications

References 9 publications

Synthesis, Structural Characterization, and Reactivity Studies of 5-CF₃SO₃-B₁₀H₁₃

Synthesis, Structural Characterization, and Reactivity Studies of 5-CF₃SO₃-B₁₀H₁₃

High Yielding Preparation of Dicarba-closo-dodecaboranes Using a Silver(I) Mediated Dehydrogenative Alkyne-Insertion Reaction

Polyhedral Carboranes

Contact Info

Product

Resources

About

Kinetics of ortho-carborane formation revisited

Cited by 7 publications

References 9 publications

Synthesis, Structural Characterization, and Reactivity Studies of 5-CF3SO3-B10H13

Synthesis, Structural Characterization, and Reactivity Studies of 5-CF3SO3-B10H13

High Yielding Preparation of Dicarba-closo-dodecaboranes Using a Silver(I) Mediated Dehydrogenative Alkyne-Insertion Reaction

Polyhedral Carboranes

Contact Info

Product

Resources

About

Synthesis, Structural Characterization, and Reactivity Studies of 5-CF₃SO₃-B₁₀H₁₃

Synthesis, Structural Characterization, and Reactivity Studies of 5-CF₃SO₃-B₁₀H₁₃