The many colours of iodine
The production of organic molecules is critical to the existence and competitiveness of industries from pharmaceuticals to agrochemicals to biomedicine. Catalysts play a critical role in this process, with small amounts speeding the rate of a reaction and enhancing product yield. Stereoselectivity, the production of only one of two nearly identical (chiral) compounds, is also of fundamental importance. Special properties of iodine-containing reagents and catalysts were exploited in the EU-funded project ‘Diaminations of alkenes using metal-free chemistry’ (DIALMEC). There is a resurgence of interest in hypervalent iodine (more than eight electrons in the outer shell) for several reasons. Among them are its similarity to heavy metal reagents but without toxicity, mild reaction conditions and ease of handling and commercial availability. Scientists successfully employed hypervalent iodine in several important reaction types. The 1,2-diamine subunit is present in a number of natural compounds and pharmaceuticals. Diamination is thus a much-studied reaction. Researchers established a route for a highly stereoselective intramolecular diamination with a novel chiral hypervalent iodine reagent. Similar reagents were used in the development of a new route for the flexible, stereoselective functionalisation of ketones. Ketones are used in polymers, solvents and pharmaceuticals. Finally, the team successfully accomplished stereoselective iodoamination of alkenes. Increasing restrictions on the use of hazardous chemicals has placed many reactions traditionally relying on heavy metal reagents under attack. DIALMEC has developed eco-friendly iodine-based reagents and catalysts to fill an important industrial need that will help EU pharmaceutical and chemical, agrochemical and pharmaceutical producers to be competitive.
Keywords
Iodine, heavy metal, diamination, stereoselectivity, ketones, alkenes
