5-Hydroxy-2(5H)-furanone (HFO) - a versatile and bio-based platform chemical

The transition toward sustainable chemistry requires a fundamental rethinking of chemical building blocks beyond fossil-derived systems. While conventional petrochemical platform chemicals are industrially indispensable, they suffer from reliance on finite resources, environmental persistence, and restricted structural diversity. In contrast, bio-based and renewable platform chemicals offer major new opportunities, particularly when exploiting the inherent functionality and structural diversity of natural metabolites through bottom-up design strategies. This review highlights 5-hydroxy-2(5H)-furanone (5-hydroxybutenolide, HFO), a chiral maleic anhydride analogue, as a promising yet underexplored bio-based platform chemical. It critically assesses its synthetic accessibility from renewable furanic feedstocks and examines key transformation strategies that enable the generation of structurally diverse and enantioenriched derivatives. Emphasis is placed on its multifunctional reactivity, which underpins its application as versatile building block in asymmetric synthesis, fine chemicals, and materials science. Additionally, its potential as a precursor to industrially relevant C4 compounds under mild and sustainable conditions is evaluated. Its broader sustainability and industrial profile are also considered, including renewability, process efficiency, scalability, techno-economic considerations, and commercial relevance. Overall, this review demonstrates HFO not merely as another bio-based intermediate but positions it as strategically valuable platform molecule whose multifunctionality, accessibility, and adaptability enable innovative chemical design. Consequently, it represents a compelling candidate for bridging the gap between renewable resources and high-value applications, supporting the development of a more sustainable and forward-looking chemical industry.