Carbonyl reduction

organic reduction of any carbonyl group by a reducing agent

Carbonyl reduction in organic chemistry is the organic reduction of any carbonyl group containing compound by a reducing agent.

QuotesEdit

  • Hydride reductions of α,β-unsaturated aldehydes and ketones may proceed via 1,2- or 1,4-additions to furnish the corresponding allylic alcohols or saturated aldehydes and ketones, respectively. … A number of chemoselective reductions of the more reactive R-CHO group in the presence of an R2CO group have been reported using 9-BBN·pyridine or K[BH(OAc)3] …
    There are few methods for effecting chemoselective reductions of ketones in the presence of aldehydes. NaBH4-CeC13-EtOH-HC(OCH3)3 reduces chemoselectively a keto group in the presence of an aldehyde and an ester group. Selective reduction of a keto group in the presence of an ester can be accomplished using either BH3· SMe, in THF or NaBH, in ethanol and H2O. … The facile reduction of the -COOH group by BH3·THF or BH3·SMe, has been employed for chemoselective reductions of the carboxyl group in the presence of ester or lactone functionalities using a stoichiometric quantity of the borane. … Treatment of DIBAL-H with one equivalent of n-BuLi generates Ei[(i-Bu)2(n-Bu)AlH], a reductant that selectively reduces esters in the presence of amides or nitriles.
    • George S. Zweifel and Michael H. Nantz, Modern Organic Synthesis (2006), Ch. 4 : Functional Group Transformations: Oxidation and Reduction
  • Generally, the diastereoselectivity in reductions of cyclic ketones with nucleophilic hydrides is determined not only by the steric congestion of the ketone but also by the nature of the nucleophilic reducing agent. … Rationalization of the stereochemical results obtained from reduction of substituted cyclohexanones with hydrides has resulted in controversy. … There are two possible modes of delivery of the "hydride" to the carbonyl carbon of cyclohexanone: (1) axial attack with formation of the equatorial alcohol and (2) equatorial attack with formation of the axial alcohol. Two factors are competing with each other: (1) steric interaction of the incoming "hydride" with the 3,5-diaxial hydrogens in the axial attack and (2) torsional strain of the incoming "hydride" with the 2,6-diaxial hydrogens in the equatorial attack.
    • George S. Zweifel and Michael H. Nantz, Modern Organic Synthesis (2006), Ch. 4 : Functional Group Transformations: Oxidation and Reduction

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