hydroboraatiohapetusreaktio

Hydroboraatiohapetusreaktio, known in English as hydroboration-oxidation, is a two-step organic chemical reaction that converts an alkene or alkyne into an alcohol. The reaction proceeds in two distinct stages. The first stage, hydroboration, involves the addition of a borane reagent (BH3) across the double or triple bond of the unsaturated hydrocarbon. This addition follows Markovnikov's rule in reverse, meaning the boron atom attaches to the less substituted carbon atom of the double or triple bond, and the hydrogen atom attaches to the more substituted carbon atom. This regioselectivity is due to the concerted, anti-Markovnikov addition mechanism, where the boron is more electropositive and the hydrogen more electronegative, leading to a syn addition.

The second stage, oxidation, replaces the boron atom with a hydroxyl group (-OH). This is typically achieved using an oxidizing agent like hydrogen peroxide (H2O2) in the presence of a base, such as sodium hydroxide (NaOH). The oxidation step also proceeds with retention of stereochemistry, meaning the configuration of the molecule at the carbon atoms involved is preserved. The overall result of hydroboration-oxidation is the anti-Markovnikov addition of water across the double or triple bond, yielding an alcohol. This reaction is highly valuable in organic synthesis for its predictable regioselectivity and stereoselectivity, allowing for the controlled synthesis of specific alcohol isomers that are difficult to obtain through other methods.