2747-53-7Relevant academic research and scientific papers
An efficient heterogeneous catalytic system for chemoselective hydrogenation of unsaturated ketones in aqueous medium
Deshmukh, Amit,Kinage, Anil,Kumar, Rajiv,Meijboom, Reinout
experimental part, p. 3262 - 3268 (2011/02/18)
A highly chemoselective and green heterogeneous catalytic system of immobilized Ru(II)-phenanthroline complexes on amino functionalised MCM-41 material for the chemoselective hydrogenation of unsaturated ketones to unsaturated alcohols is demonstrated using water as a solvent. The XRD and FTIR spectra show the highly ordered hexagonal nature of the MCM-41, even after encapsulation of the ruthenium complex. The complex retains its configuration after anchoring, as was confirmed by FTIR and UV-Vis analysis. The detailed reaction parametric effect was studied for the hydrogenation of 3-methylpent-3-en-2-one to achieve complete conversion up to >99% chemoselectivity of 3-methylpent-3-en-2-ol. The anchored heterogeneous catalysts were recycled effectively and reused five times with marginal changes in activity and selectivity. The use of water as a solvent not only afforded high activity for the hydrogenation reaction compared to organic solvents, but also afforded a green process.
Ate Complex from Diisobutylaluminum Hydride and n-Butyllithium as a Powerful and Selective Reducing Agent for the Reduction of Selected Organic Compounds Containing Various Functional Groups
Kim, Sunggak,Ahn, Kyo Han
, p. 1717 - 1724 (2007/10/02)
The "ate" complex generated from diisobutylaluminum hydride and n-butyllithium in an equimolar ratio either in tetrahydrofuran-hexane or in toluene-hexane was reacted with a series of selected organic compounds containing various functional groups in order to explore the reducing properties and to determine the synthetic utility of the reagent.The reagent is very effective for selective 1,2-reduction of both acyclic and cyclic enones.The reagent in tetrahydrofuran-hexane gives slightly better 1,2-selectivity than in toluene-hexane in the reduction of some acyclic enones, whereas the reagent in toluene-hexane gives better 1,2-selectivity in the reduction of conjugated cyclohexenones.Esters and lactones are completely reduced to the corresponding alcohols at room temperature, whereas they are reduced to the corresponding alcohols and aldehydes at -78 deg C even with an excess amount of the reagent.Partial reduction of the esters and the lactones to the corresponding aldehydes has not been observed.Acid chlorides are rapidly reduced to the corresponding alcohols with an excess amount of the reagent at -78 deg C, whereas they are reduced to a mixture of the alcohol, the aldehyde, and the unreacted acid chloride with a stoichiometric amount of the reagent at -78 deg C.Acid anhydrides are rapidly and quantitatively reduced to an equimolar mixture of the acid and the alcohol at -78 deg C.Carboxylic acids and primary and secondary amides are inert to the reagent at room temperature and are recovered unchanged..Tertiary amides are cleanly reduced to the aldehydes with a stoichiometric amount of the reagent either at 0 deg C or at room temperature, whereas they are inert to the reagent at -78 deg C, which permits the selective reduction of other reducible functional groups in the presence of the tertiary amide group at the latter temperature.The reagent rapidly reduces simple primary alkyl, benzyl, and allyl bromides but slowly primary alkyl chlorides and secondary alkyl bromides.Tertiary alkyl and aryl halides are essentially inert to the reagent, whereas trityl bromide and vinyl bromide are reduced at a reasonable rate.Epoxides are cleanly reduced to the corresponding alcohols.The opening of the epoxide ring with this reagent proceeds with excellent isomeric purity, yielding the more highly substituted alcohol almost exclusively.Nitriles are resistant to reduction and are only slowly converted to the corresponding aldehydes at room temperature.Disulfides are rapidly and quantitatively reduced to the corresponding thiols.Sulfoxides and sulfones are inert to the reagent and are recovered unchanged.Selective reductions of an ester in the presence of other reducible groups such as a bromide, a tertiary amide, and a nitrile are achieved with the reagent at -78 deg C by using a modified procedure.Furthermore, the reagent is capable of reducing selectively a ketone in the presence of an ester.
