767-54-4Relevant academic research and scientific papers
Stereoselectivity of lithium aluminium hydride and lithium alkoxyaluminohydride reductions of 3,3,5-trimethylcyclohexanone in diethyl ether
McMahon, Robert J.,Wiegers, Karl E.,Smith, Stanley G.
, p. 99 - 101 (1981)
The stereochemistry of lithium aluminum hydride and lithium tert-butoxyaluminohydride reductions of 3,3,5-trimethylcyclohexanone in diethyl ether has been studied.An unusual nonmonotonic dependence of the percentage of trans-3,3,5-trimethylcyclohexanol formed upon the ratio of : is observed.These unusual results have led to the use of diol addends to LiAlH4 solutions in order to probe the role of disproportionation upon stereoselectivity.Lithium mono-tert-butoxyaluminohydride is proposed to have a radically different stereoselectivity from that of either LiAlH4 or LiAl(O-t-Bu)3H.
Reaction of Lithium Aluminum Hydride with Hindered Phenols. Formation of Tricoordinate Aluminum Species
Haubenstock, Howard,Mester, Theodore A.,Zieger, Herman
, p. 3443 - 3448 (1980)
Lithium aluminum hydride reacts readily with 3 molar equiv of 2,4,6-tri-tert-butylphenol in refluxing ether.It has been demonstrated that the products resulting from this reaction cause the conversion of axial to equatorial cyclohexanols in the presence of a ketone.This behaviour is attributed to the formation of tricoordinate aluminum species.An ether solution of bis(2,4,6-tri-tert-butylphenoxy)aluminum hydride was prepared, and infrared spectra provide evidence for the existence of this species in solution resulting from the reaction of LiAlH4 with 3 molar equiv of 2,4,6-tri-tert-butylphenol.
DIASTEREOSELECTIVE REDUCTIONS OF CYCLOHEXANONES WITH DIISOBUTYLALUMINUM 2,6-DI-t-BUTYL-4-METHYLPHENOXIDE
Haubenstock, Howard
, p. 6633 - 6636 (1990)
Isomerization of aluminum alcoholates occurs in the reduction of cyclohexanones with diisobutylaluminum 2,6-di-t-butyl-4-methylphenoxide 1 in the presence of excess ketone.Factors affecting the diastereoselectivity of reduction of cyclohexanones with 1 were investigated.
On the Reaction of Lithium Aluminum Hydride with Alcohols
Haubenstock, H.,Mester, T.
, p. 945 - 948 (1983)
Infrared spectra of the reaction products of lithium aluminum hydride (LiAlH4) with 3 molar equiv of isobutyl alcohol, 2-propanol, and the more sterically hindered 2,4-dimethyl-3-pentanol, 4, in diethyl ether were examined.Alcohol 4 reacts with LiAlH4 in diethyl ether, giving a clear solution that is highly stereoselective in the reduction of 3,3,5-trimethylcyclohexanone, 1.The reaction of LiAlH4 with 4 does not lead to tricoordinate aluminum species.On the basis of infrared spectra and the stereochemistry of reduction of 1, it is concluded that LiAlH4 is presentin solution after its reaction with 3 molar equiv of isobutyl alcohol.LiAlH4 is also the initial reducing species in solution after reaction with 2-propanol.On the other hand, LiAlH4 reacts with methanol, ethanol, and 4, giving lithium alkoxyaluminum hydride species.Possible pathways for the reaction of LiAlH4 with alcohols are discussed.
Reduction of Ketones by Tributyltin Hydride: The Effect of High Pressure on Steric Hindrance and Rearrangement Processes
Degueil-Castaing, Marie,Rahm, Alain
, p. 1672 - 1676 (1986)
The reduction of sterically hindered ketones by tributyltin hydride under high pressure (1 GPa) afforded the corresponding alcohols in good yields without the need of free radical initiator or Lewis acid catalyst.Cyclopropyl ketones and α,β-epoxy ketones were also reduced in high yields under 1400 MPa with preservation of the three-membered ring.
Heterogeneous Hydroxyl-Directed Hydrogenation: Control of Diastereoselectivity through Bimetallic Surface Composition
Shumski, Alexander J.,Swann, William A.,Escorcia, Nicole J.,Li, Christina W.
, p. 6128 - 6134 (2021/05/29)
Directed hydrogenation, in which product selectivity is dictated by the binding of an ancillary directing group on the substrate to the catalyst, is typically catalyzed by homogeneous Rh and Ir complexes. No heterogeneous catalyst has been able to achieve equivalently high directivity due to a lack of control over substrate binding orientation at the catalyst surface. In this work, we demonstrate that Pd-Cu bimetallic nanoparticles with both Pd and Cu atoms distributed across the surface are capable of high conversion and diastereoselectivity in the hydroxyl-directed hydrogenation reaction of terpinen-4-ol. We postulate that the OH directing group adsorbs to the more oxophilic Cu atom while the olefin and hydrogen bind to adjacent Pd atoms, thus enabling selective delivery of hydrogen to the olefin from the same face as the directing group with a 16:1 diastereomeric ratio.
The Stereoselective Reductions of Ketones to the Most Thermodynamically Stable Alcohols Using Lithium and Hydrated Salts of Common Transition Metals
Kennedy, Nicole,Cohen, Theodore
, p. 8134 - 8141 (2015/09/02)
A simple method is presented for the highly stereoselective reductions of ketones to the most thermodynamically stable alcohols. In this procedure, the ketone is treated with lithium dispersion and either FeCl2·4H2O or CuCl2·2H2O in THF at room temperature. This protocol is applied to a large number and variety of ketones and is both more convenient and efficient than those commonly reported for the diastereoselective reduction of five- and six-membered cyclic ketones.
Selective reduction of organic compounds with Al- trifluoromethanesulfonyldiisobutylalane. Comparison of its reactivity with Al-methanesulfonyldiisobutylalane
Cha, Jin Soon
experimental part, p. 219 - 224 (2011/11/06)
The new MPV type reagent, Al-trifluoromethanesulfonyldiisobutylalane (DIBAO3SCF3), has been prepared and its reducing characteristics in the reduction of selected organic compounds containing representative functional groups have been examined, and compared its reactivity with that of Al-methanesulfonyldiisobutylalane (DIBAO3SCH 3) in order to understand the fluorine-substituent effect on its reactivity. In general, the reactivity of DIBAO3SCF3 appears to be much higher than that of DIBAO3SCH3, apparently due to the acidity increase by the electron-withdrawing fluorine-substituent. The reagent reduced aldehydes and ketones readily, but showed a perfect selectivity in the reduction of α,β-unsaturated aldehydes and ketones to produce the corresponding allylic alcohols in an absolutely 100% purity. In addition, the reagent achieved the regioselective cleavage of phenyl-or/and alkyl-substituted epoxides to the less substituted alcohols in a perfect regioselectivity. Moreover, the reagent also showed an high stereoselectivity in the reduction of substituted cycloalkanones to produce the thermodynamically more stable alcohol epimers exclusively.
Selective reduction of organic compounds with Al- methanesulfonyldiisobutylalane
Cha, Jin Soon,Noh, Minyeong
experimental part, p. 840 - 844 (2010/10/21)
The new MPV type reagent, Al-methanesulfonyldiisobutylalane (DIBAO 3SCH3), has been prepared and its reducing characteristics in the reduction of selected organic compounds containing representative functional groups have been examined in order to find out a new reducing system with high selectivity in organic synthesis. In general, the reagent is extremely mild, showing only reactivity toward aldehydes, ketones and epoxides. The reagent exhibits a unique reducing applicability in organic synthesis. Thus, the reagent can achieve a clean 1,2-reduction of α,β-unsaturated aldehydes and ketones to produce the corresponding allylic alcohols in 100% purity. In addition, the reagent shows an excellent regioselectivity in the ring-opening reaction of epoxides. Finally, DIBAO3SCH3 shows a high stereo-selectivity in the reduction of cyclic ketones to produce the thermodynamically more stable epimers exclusively.
Al-isopropoxydiisobutylalane: A study of the effect of solvent on the rate and stereoselectivity of cyclic ketone reduction
Bahia, Perdip S.,Jones, Matthew A.,Snaith, John S.
, p. 9289 - 9291 (2007/10/03)
The effect of solvent on the rate and stereoselectivity of cyclic ketone reduction by Al-isopropoxydiisobutylalane (DIBAiOPr) has been investigated. In dichloromethane, DIBAiOPr behaves as a bulky reducing agent, approaching the carbonyl group along an equatorial trajectory to produce the axial alcohol with > 10:1 stereoselectivity. In sharp contrast, reduction in toluene gives the complementary outcome, affording the thermodynamically more stable isomer with > 99:1 stereoselectivity.
