• Journal of the Korean Chemical Society
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• v.22 no.4
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• pp.259-267
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• 1978

In order to find out the selective reducing characteristics of lithium borohydride, borane, and borane-lithium chloride (1 : 0.1) in the reduction of carbonyl compounds, five representative equimolar mixtures of carbonyl compounds were chosen; benzaldehyde-acetophenone, benzaldehyde-2-heptanone, 2-heptanone-benzophenone, acetophenone-benzophenone, and 2-heptanone-acetophenone, and reacted with limited amount of lithium borohydride, borane or borane-lithium chloride (1 : 0.1) in tetrahydrofuran (THF) at $0^{\circ}$. Borane-lithium chloride (1 : 0.1) showed the excellent selectivity, however, lithium borohydride and borane also exhibited good selectivity except for the 2-heptanone-acetophenone.

• Bulletin of the Korean Chemical Society
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• v.4 no.1
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• pp.14-17
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• 1983

The effects of trialkylborane on the stereochemistry of ketone reduction with lithium borohydride were studied for the four representative ketones, namely 4-t-butylcyclohexanone, 2-methylcyclohexanone, norcamphor, and camphor. The presence of trialkylborane increased the yields of the less stable alcohols. For example, in the presence of tri-s-butylborane, 42 % yield of cis-4-t-butylcyclohexanol was observed whereas only 8 % yield with lithium borohydride alone in the reduction of 4-t-butylcyclohexanone. The in situ formation of lithium trialkylborohydride, by the hydride transfer from lithium trialkoxyborohydride to trialkylborane, was demonstrated as a possible mechanism for the catalytic effect of trialkylborane.

• Analytical Science and Technology
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• v.31 no.1
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• pp.1-6
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• 2018

We used differential scanning calorimetry and a thermogravimetric analysis to investigate the effect of being confined in mesoporous MCM-41 on the decomposition of lithium borohydride and magnesium borohydride when heated. The confinement did not cause a phase transition of the metal borohydrides inside MCM-41, but did lower their decomposition temperature. With the exception of a lowering of the temperature, the decomposition reaction mechanism of the metal borohydrides was nearly the same for both the bulk and confined samples.

• Bulletin of the Korean Chemical Society
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• v.9 no.5
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• pp.322-324
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• 1988

Selective reduction of aldoximes and ketoximes with lithium borohydride in tetrahydrofuran was investigated. Thus, aldoximes and cyclic ketoximes such as hexanaldoxime, heptanaldoxime, cyclopentanone oxime and cyclohexanone oxime were reduced smoothly to the corresponding N-monosubstituted hydroxylamines at room temperature in 65-93% yield. The reduction of alicyclic ketoxime was very slow, requiring somewhat high reaction temperature ($65^{\circ}C$) for the complete reduction to give the hydroxnylamines. The reduction of aromatic oximes such as benzaldoxime and acetophenone oxime was very sluggish, giving a mixture of the corresponding hydroxylamines and amines at $65^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.8 no.1
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• pp.4-5
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• 1987

${\beta}$-Naphthoxyboranes and lithium tri-${\beta}$ -naphthoxyborohydride were prepared and their properties were investigated by 11B-NMR. The reducing power of lithium tri-${\beta}$ -naphthoxyborohydride is weaker than lithium borohydride.

• Journal of the Korean Chemical Society
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• v.27 no.1
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• pp.46-52
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• 1983

Selective reduction of halide (Br, I) with lithium borohydride in halogen compounds containing chloro, nitro, ester and nitrile groups was achieved satisfactorily. 1-Bromo-4-chlorobutane was reduced to 1-chlorobutane in 96% yield and the reduction of p-nitrobenzyl bromide gave p-nitrotoluene in 98% yield. However, the selectivity on the reduction of ethyl 3-iodopropionate and 4-bromobutyronitrile required the presence of equimolar pyridine to give good yield of ethyl propionate (93%) and n-butyronitrile (88%), respectively. In competitive reduction of 1-bromoheptane and 2-bromoheptane, lithium borohydride reduced 1-bromoheptane preferentially in the molar ratio of 93:7.

• Bulletin of the Korean Chemical Society
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• v.23 no.6
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• pp.856-861
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• 2002

The general reducing charagteristics of a newly synthesized reducing agent, lithium(2.3-dimethyl-2-butyl)-${\iota}$-butoxyborohydride (Li $Thx'BuOB_2$, 1), in tetrahydrofuran (THF) toward selected organic compounds containing representative fundtional groups under practical has been examined. The reagent revealed an interesting and unique reducing characteristics. Especially, the stereoselectivity in the reduction of cyclic ketones was extraordinary. Thus, the introduction of bulky alkyl and alkoxy groups into the parent borohydride affonds a high stereoselectivity. In general, the reducing power of the reagent is somewhere between the dialiylborohydride and the parent borohydride. This permits the reagent to be a reagent of choice for selecitive reduction of organic compounds with an improved selectivity.

• Journal of the Korean Chemical Society
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• v.21 no.2
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• pp.108-120
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• 1977

The approximate rates and stoichiometries of the reaction of lithium borohydride, with fifty two selected organic compounds containing representative functional groups under the standard condition (tetrahydrofuran, $0^{\circ}$), were studied.Among the active hydrogen compounds,primary alcohols and compounds containing an acidic proton liberated hydrogen relatively fast, but secondary and tertiary alcohols very sluggishly. All the carbonyl compounds examined were reduced rapidly within one hour. Especially, among the ${\alpha}{\beta}$-unsaturated carbonyl compounds tested, the aldehydes consumed one hydride cleanly, however the cyclic ketones consumed more than one hydride even at $-20^{\circ}$. Carboxylic acids were reduced very slowly, showing about 60% reduction in 6 days at $25^{\circ}$, however acyl chlorides reduced immediately within 30 minutes. On the other hand, the reductions of cyclic anhydrides proceeded moderately to the hydroxy acid stage, however the further reductions were very slow. Aromatic and aliphatic esters, with exception of the relatively moderate reduction of acetate, were reduced very slowly, however lactones were reduced at a moderate rate. Epoxides reacted slowly, but amides and nitriles as well as the nitro compounds were all inert to this reagent. And cyclohexanone oxime and phenyl isocyanate were reduced very sluggishly. Last of all, all sulfur compounds studied were inert to this hydride.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.296-298
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• 2005

Hydrogen generation by the hydrolysis of aqueous sodium borohydride $(NaBH_4)$ solutions was studied using IRA-400 anion resin dispersed Pt. Ru catalysts and Lithium Cobalt oxide $(LiCoO_2)$ supported Pt, Ru and PtRu catalysts. The performance of the $LiCoO_2$ supported catalysts is better than the ion exchange resin dispersed catalysts. There is a marked concentration dependence on the performance of the $LiCoO_2$ supported catalysts and the hydrogen generation rate goes down if the borohydride concentration is increased beyond $10\%$. The efficiency of PtRu- $LiCoO_2$ is almost double that of either Ru-$LiCoO_2$ or Pt-$LiCoO_2$ for $NaBH_4$ concentrations up to $10\%$.

• Journal of the Korean Chemical Society
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• v.52 no.3
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• pp.338-340
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• 2008