Hydroiodic acid (HI)
Mechanism + Description
Reduction occurs when treated with hot HI. Mechanism is probably electron transfer - protonation
Reaction is generally selective in the presence of other reducible functional groups (not compatible with hydrolysable groups) but requires a lot of HI and thus is poor on atom economy. Incineration of waste streams could be problematic (iodine content). Limited utility for waste by-products. Iodine is an element at medium to high risk of depletion. High LCA reagent, although it is possible to recover iodide from waste materials.
Relevant scale up example