oxetane

Oxetane, also known as 1-oxacyclobutane, is a saturated heterocyclic compound consisting of a four-membered ring with three carbon atoms and one oxygen atom. Its molecular formula is C3H6O. It is the parent member of the oxetane family, and many substituted derivatives are known.

The four-membered ring is highly strained, producing notable angle strain and reactivity toward ring-opening. The oxygen atom confers polarity. Oxetane itself is typically a colorless liquid at room temperature, and many derivatives are liquids or solids depending on substituents. Reactions include nucleophile-promoted ring-opening to yield beta-hydroxy compounds, and cationic or coordination-assisted ring-opening polymerization to form polyoxetanes.

Key synthetic routes include the photochemical Paternò–Büchi [2+2] cycloaddition of alkenes with carbonyl compounds, which directly furnishes oxetanes. Other routes involve intramolecular cyclization of suitable hydroxyalkyl halides or alkoxide precursors, and various ring-closure strategies from linear precursors.

Oxetane rings are reactive toward acids and bases and can undergo ring-opening polymerization under appropriate conditions, yielding polyether materials. They are valuable motifs in organic synthesis and materials science, with oxetane-containing monomers used to tailor properties of polymers and networks.

Applications span polymer chemistry, materials science, and medicinal chemistry, where the oxetane scaffold can influence polarity, lipophilicity, and metabolic stability. The family encompasses many substituted and fused oxetanes, including heterobicyclic or spirocyclic oxetanes used in research and development.