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  • Alkenes do not undergo hydration upon treatment with water even at very high temperatures. There are two approaches to hydrating alkenes:

    1. Reaction of the alkene with water in the presence of a strong-acid catalyst.
    2. Using an indirect method, such as oxymercuration-reduction, also known as oxymercuration-demercuration or, simply, oxymercuration.



    net reaction:


    The protocol is carried out in two stages:

    Stage 1: Oxymercuration: The alkene is treated with aqueous mercury (II) acetate, Hg(OAc)2, which converts the alkene into an organomercury compound (see organometallic compound).

    Stage 2: Reduction (Demercuration): The organomercury compound is treated with a reducing agent, usually NaBH4, which converts the organomercury compound into an alcohol.

    eg: Stage 1:


    The reaction is an anti addition.

    Stage 2:


    Stage 1 + Stage 2 =

    The net reaction is a Markovnikov addition:


    see also hydroboration-oxidation