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Ketone Enolates

  • Page ID
    22904
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    Bases

    ketone-BuLi.pngKetone-bases.png

    Kinetic vs. Thermodynamic Enolate

    Enolate Regiochemistry must also be considered...

    KvT-intro.png

    If we consider the energetics of the reaction, we can selectively produce one enolate.

    KvT-energy diagram.png

    KvT-ex1.png

    KvT-ex2.png

    Carbon vs. Oxygen Nucleophilicity

    Ketones can be alkylated by very reactive electrophiles:

    ketone-alkylation.png

    Enolates can act as nucleophiles at either the carbon or oxygen termini. The oxygen center acts as a hard nucleophiles while the carbon center acts as a soft nucleophile.

    ketones-hardsoft.png

    O alkylation can be favored by several methods

    ketones-Oalkylation.png

    Stereochemistry

    Cyclohexanones

    cyclohex-A12.png

    cyclohex-A12ex.png

    cyclohex-halfchair.png

    β-vetivone

    The Stork synthesis of β-vetivone provides an elegant use of this selectivity.vetivone-retro.png

    vetivone synth.png

    SAMP/RAMP

    For unreactive enolates, the hydrazone can be formed and deprotonated with n-BuLi. This provides a metallo-enamine which is very reactive. Metallo-enamines will even react with poor electrophiles.

    metallo-enamine.png

    This alkylation can be rendered enantioselective by use of SAMP or RAMPSAMP.png


    Ketone Enolates is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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