Advanced Topic 872 of 1102 Organic Chemistry
Hydroboration-Oxidation
Anti-Markovnikov syn hydration of alkenes using borane then peroxide.
In-depth explanation of Hydroboration-Oxidation
Hydroboration-oxidation converts an alkene into an alcohol with anti-Markovnikov regiochemistry and syn stereochemistry. Borane, BH3, adds across the double bond in a single concerted step, with boron attaching to the less hindered carbon and hydrogen to the more substituted carbon. Treatment with hydrogen peroxide and sodium hydroxide then replaces the boron with an OH group, with retention of configuration. Because there is no carbocation, rearrangements do not occur, which makes the method reliable for preparing primary alcohols from terminal alkenes.
Going deeper: Hydroboration-Oxidation
Key ideas: BH3 in THF adds across an alkene with boron on the less hindered carbon and H on the more substituted, in a concerted syn fashion, repeated three times to form trialkylborane. Oxidation with H2O2 and NaOH replaces B with OH, with retention. Net result: syn anti-Markovnikov hydration, no carbocation, no rearrangement. Terminal alkynes give aldehydes with a bulky borane (disiamylborane), then H2O2.
Common mistakes and connections: Students expect the Markovnikov alcohol or a carbocation rearrangement. Another error is forgetting syn stereochemistry or using acid in the oxidation step. Links to hydration of alkenes, anti-Markovnikov addition and regioselectivity governed by sterics and electronics (Nobel 1979 to H. C. Brown).
Visualization of Hydroboration-Oxidation
Borane adds across the alkene in one syn step with boron on the less substituted carbon; oxidation replaces boron with OH. The interactive lesson shows this as a live animation or chart.
Worked example and use case
1-Hexene is converted by hydroboration-oxidation into 1-hexanol.
Frequently asked questions about Hydroboration-Oxidation
What is Hydroboration-Oxidation?
Anti-Markovnikov syn hydration of alkenes using borane then peroxide.
Is Hydroboration-Oxidation a beginner, intermediate or advanced topic?
Hydroboration-Oxidation is a advanced topic in Organic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Hydroboration-Oxidation?
Study these earlier topics in Organic Chemistry first: Reduction of Carbonyls, Epoxides, Sharpless Epoxidation.
What comes after Hydroboration-Oxidation?
The next topics in Organic Chemistry are Baeyer-Villiger Oxidation and Beckmann Rearrangement.
Can I practise Hydroboration-Oxidation with quizzes?
Yes. The interactive lesson includes a self-check question on Hydroboration-Oxidation, and the Organic Chemistry quiz draws on every topic in this area.
Where Hydroboration-Oxidation fits in Organic Chemistry
Hydroboration-Oxidation is topic 144 of 148 in Organic Chemistry.