Epoxide hydrolysis
Protonation activates the strained ring toward attack by water. Backside attack breaks one C-O bond; proton transfer leaves hydroxyl groups on adjacent carbons, with an anti relationship when ring geometry makes that distinction meaningful.
- Reagents
- Dilute aqueous acid
- Conditions
- Acid-catalysed ring opening with water
- Reaction class
- Epoxide hydrolysis
- Equation
- epoxide + H2O -> vicinal diol
Overview
Protonation activates the strained ring toward attack by water. Backside attack breaks one C-O bond; proton transfer leaves hydroxyl groups on adjacent carbons, with an anti relationship when ring geometry makes that distinction meaningful.
Transformation
- Equation
- epoxide + H2O -> vicinal diol
- Reagents
- Dilute aqueous acid
- Environment
- Acid-catalysed ring opening with water
- Reaction class
- Epoxide hydrolysis
- Mechanism
- acid-catalysed nucleophilic ring opening
- Evidence level
- textbook extension
Scope and limitations
- Scope
- Water opens the ring to place OH groups on adjacent carbons.
- Limitations
- Backside opening gives anti stereochemistry; substrate substitution affects regioselectivity.
Related reactions
- Dihydroxylation: Alkenes → Diols
Cold, dilute manganate(VII) oxidises an alkene to a vicinal diol without the oxidative cleavage associated with stronger conditions.
- Polyester formation co reactant: Diols → Polyesters
Diols condense with dicarboxylic acids to form polyesters.
- Epoxidation: Alkenes → Epoxides
A peroxyacid transfers oxygen across the alkene in a concerted step, forming two C-O bonds while breaking the C=C pi bond. Both bonds form from one face, retaining the alkene substituents’ relative stereochemistry in the epoxide.
References
- Organic Chemistry: Reactions of Epoxides: Ring-OpeningJohn McMurry · OpenStax Organic Chemistry · 2023
Supports functional-group chemistry used to curate the linked examples. Checked 2026-09-16; named examples are applications of textbook scope, without claimed experimental yields.