Electrochemical Halocyclization‐Enabled Synthesis of Tetrahydrofuran Derivatives With KBr/ KI

Tetrahydrofuran (THF) frameworks are privileged scaffolds prevalent in bioactive natural products and pharmaceuticals, yet the stereocontrolled synthesis of polysubstituted derivatives remains a significant challenge. While conventional methods often rely on transition‐metal catalysis, they are frequently hampered by issues such as β‐hydride elimination and the requirement for stoichiometric oxidants. In contrast, organic electrosynthesis offers a sustainable alternative by using electron transfer to activate substrates, eliminating the need for external oxidants and improving atom economy. Building on recent advances in electrochemical halogenation, this method proposes a novel and efficient strategy for constructing THF rings. We envisioned an electrochemical 1,5‐halocyclization of alkenols using inexpensive metal halides as dual‐function halogen sources and electrolytes. This anode‐driven process enables rapid assembly of the THF core, producing molecular hydrogen as the sole byproduct. This method represents a green, atom‐economical, and operationally simple approach to valuable O‐heterocycles.