Dihydrofuran-3(2H)-one
[CAS 22929-52-8]

Identification

• Classification: Organic raw materials >> Ketone compound
• Name: Dihydrofuran-3(2H)-one
• Synonyms: oxolan-3-one
• Molecular Formula: C₄H₆O₂
• Molecular Weight: 86.09
• CAS Registry Number: 22929-52-8
• EC Number: 805-925-0
• SMILES: C1COCC1=O

Properties

• Density: 1.1±0.1 g/cm³ Calc.^*
• Boiling point: 151.1±23.0 °C 760 mmHg (Calc.)^*, 139 - 140 °C (Expl.)
• Flash point: 56.3±16.2 °C (Calc.)^*
• Index of refraction: 1.442 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02;GHS07 DangerGHS02;GHS02
• Risk Statements: H225-H226-H302-H315-H319-H335
• Safety Statements: P210-P233-P240-P241-P242-P243-P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P303+P361+P353-P304+P340-P305+P351+P338-P319-P321-P330-P332+P317-P337+P317-P362+P364-P370+P378-P403+P233-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - single exposure	STOT SE	3	H335
Flammable liquids	Flam. Liq.	3	H226
Eye irritation	Eye Irrit.	2A	H319
Flammable liquids	Flam. Liq.	2	H225

Discovery and Applications

Dihydrofuran-3(2H)-one is a five-membered cyclic oxygen-containing ketone belonging to the class of lactone-related heterocyclic compounds known as cyclic ethers with carbonyl functionality. It is commonly described as a saturated or partially saturated furanone derivative in which a carbonyl group is incorporated into a five-membered ring containing one oxygen atom. The compound is characterized by the combination of an ether oxygen within the ring and a ketone carbonyl group.

The molecular structure consists of a five-membered heterocyclic ring containing one oxygen atom and four carbon atoms, with a ketone carbonyl located at the 3-position. The designation 3(2H)-one indicates that the carbonyl group is present at carbon 3 and that the ring oxygen is in the 2H tautomeric numbering form. The molecule contains no carbon–carbon double bonds outside the carbonyl group and therefore belongs to the class of saturated cyclic ketones containing an ether oxygen.

The ring oxygen atom is part of an ether linkage and is connected to two carbon atoms through single bonds. It is sp³-hybridized and possesses two lone pairs of electrons. These lone pairs allow the oxygen atom to function as a hydrogen bond acceptor but not as a hydrogen bond donor because the molecule contains no O–H bond.

The carbonyl carbon at the 3-position is sp²-hybridized and adopts trigonal planar geometry. The carbon–oxygen double bond is strongly polarized, giving the carbonyl carbon electrophilic character and the oxygen atom nucleophilic character. The carbonyl oxygen serves as a hydrogen bond acceptor and contributes significantly to the polarity of the molecule.

The five-membered ring is not planar because the saturated carbon atoms are sp³-hybridized. Instead, it adopts puckered conformations that reduce torsional strain. These conformational changes occur through rotation around single bonds within the ring while maintaining the stability of the cyclic ether framework.

The molecule contains a localized carbonyl group but no extended conjugated π-system. Therefore, electronic delocalization is limited primarily to the carbonyl functionality. The ether oxygen exerts an inductive electron-withdrawing effect on adjacent carbon atoms, influencing the electron distribution of the ring.

From a physicochemical perspective, dihydrofuran-3(2H)-one is a polar organic compound because it contains both an ether oxygen and a ketone carbonyl. These two oxygen atoms provide hydrogen bond acceptor sites and generate a significant molecular dipole. The absence of hydrogen bond donors limits its ability to form strong hydrogen-bond networks compared with alcohols or amides.

The small ring size and oxygen-containing structure contribute to compatibility with polar solvents. At the same time, the hydrocarbon portion of the ring provides limited hydrophobic character. The balance between these features gives the molecule intermediate polarity compared with simple cyclic ethers and more highly functionalized oxygen-containing compounds.

Chemically, the ketone carbonyl is the primary reactive site. It can undergo nucleophilic addition reactions with suitable nucleophiles, reduction to the corresponding cyclic alcohol, and condensation reactions under appropriate conditions. The cyclic ether oxygen is comparatively stable but can be protonated under strongly acidic conditions, potentially leading to ring-opening reactions.

The carbon atoms adjacent to the carbonyl group may participate in reactions involving enolate formation because their hydrogen atoms are activated by the electron-withdrawing effect of the carbonyl group. These enolate intermediates can undergo carbon–carbon bond-forming reactions under suitable conditions.

The cyclic ether structure provides additional reactivity compared with acyclic ketones because ring strain and neighboring oxygen effects can influence reaction pathways. However, the five-membered ring is relatively stable due to its favorable geometry and low ring strain compared with smaller cyclic ethers.

Overall, dihydrofuran-3(2H)-one is a five-membered cyclic ether ketone containing a ring oxygen and a carbonyl group within a saturated heterocyclic framework. Its polarity, hydrogen-bond acceptor ability, carbonyl reactivity, and conformational flexibility define its chemical properties and make it a representative compound among oxygen-containing heterocyclic ketones.

References

2025. Highly Efficient Asymmetric Synthesis of Aliphatic Chiral Secondary Alcohols by Whole Cells of E. coli Co-Expressing Alcohol Dehydrogenase and Glucose Dehydrogenase. Catalysis Letters.
DOI: 10.1007/s10562-025-04970-5

2025. Engineered enzymes for the synthesis of pharmaceuticals and other high-value products. Nature Synthesis.
DOI: 10.1038/s44160-023-00417-0

2022. Synthesis of dihydrofuran-3-one and 9,10-phenanthrenequinone hybrid molecules and biological evaluation against colon cancer cells as selective Akt kinase inhibitors. Molecular Diversity.
DOI: 10.1007/s11030-022-10458-w