Rhodium-Catalyzed Generation of Anhydrous Hydrogen Iodide: An Effective Method for the Preparation of Iodoalkanes.

Abstract

This study describes a novel rhodium-catalyzed approach for generating anhydrous hydrogen iodide (HI) directly from molecular hydrogen (H2) and iodine, reported here for the first time. The anhydrous HI produced demonstrated high reactivity toward a range of substrates—including alkenes, phenyl aldehydes, alcohols, and cyclic ethers—enabling their conversion to the corresponding iodoalkanes with excellent atom economy. This methodology provides a practical and efficient route for iodoalkane preparation in organic synthesis, circumventing the limitations associated with aqueous HI systems.

Mechanism

A rhodium catalyst facilitates the direct combination of molecular hydrogen and iodine to yield anhydrous HI, which subsequently reacts with alkenes, aldehydes, alcohols, and cyclic ethers to produce iodoalkanes with high atom economy.