The NMR spectra of CH3AlCl2. Donor complexex in the presence of a small excess of [CH3AlCl2]2 or donor

Wanders, A. C. M.; Konijnenberg, E.

doi:10.1016/s0040-4039(00)91018-9

Cited by 2 publications

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“…The different rates of the reduction of ketones by the various organoaluminum compounds used can be therefore rationalized on the basis of a different electronegativity of the aluminum atom in the aluminum alkyl and in the etherates. 25 The further decrease of the reduction rate in ethereal solvent might be explained in this case with a competition of ether and ketone in the solvating reaction of the organoaluminum etherate (eq 5, 6).26…”

Section: Discussionmentioning

confidence: 99%

Alkyl metal asymmetric reduction. III. Stereochemistry of alkyl phenyl ketone reductions by chiral organoaluminum compounds

Giacomelli¹,

Menicagli²,

Lardicci³

1973

J. Org. Chem.

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The asymmetric reduction of a series of alkyl phenyl ketones by optically active organoaluminum compounds, having ^-branched alkyl groups, has been studied. The reactions, which have been carried out at 0°, afforded (S)-alkylphenykarbinols in good yield. The extent of the asymmetric reduction was found to depend on the structure of the ketone employed and to be affected by the presence of a donor ligand to the aluminum atom.Moreover the reduction of isopropyl phenyl ketone by chiral solvates of triisobutylaluminum occurs with low but definite asymmetric induction. The overall results, which are consistent with a /3-hydride transfer from the alkyl group of the organoaluminum compound to the carbonyl carbon atom, are interpreted as indicating that, in the presence of ethers, the reaction occurs without prior dissociation of the ligand from the aluminum atom in cyclic six-membered-ring transition states. The stereoselectivity of the reduction process is rationalized in terms of steric and electronic interactions in competing transition states for the hydrogen-transfer step.

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Section: Discussionmentioning

confidence: 99%