CHALCOGENISATION OF UNSATURATED ORGANOHALOGEN COMPOUNDS BY ELEMENTAL CHALCOGENS AND THEIR METAL DERIVATIVES

The presented review addresses the prospects for application of organochalcogen compounds in various fields of technology, medicine, agriculture and organic synthesis. The unsaturated chalcogenisation products appear to be of much greater interest compared to their saturated analogues, especially in organic synthesis. This study observes halogen derivatives of ethene, propene, propyne and butene subjected to chalcogenisation as unsaturated substrates. The indicated reagents are related either to large-tonnage products of industrial organochlorine synthesis or waste products of organochlorine production with their disposal presenting an important environmental task. According to analysed publications, chalcogenisation processes are based on the application of elemental chalcogens (sulphur, selenium, and tellurium) or their available metal derivatives (Na2S, etc.). In the reactions of chalcogens with unsaturated halogen derivatives, the elements both in an accessible form and in a free state are subjected to reductive activation resulting in the formation of anionic nucleophilic reagents. Complex metal hydrides, chalcogenide anions and rongalite are exampled for application in terms of reducing agents. The review emphasises the prospects of basic reduction systems based on hydrazine hydrate in activation processes. Special aspects in the introduction of caustic alkalis and an monoethanolamine organic amine as bases in these systems are described. For the considered chalcogenisation processes, conditions are specified providing the most optimal yield of certain products. In some particular cases, the stereochemistry of the obtained compounds is presented considering the formation conditions for the stereoisomers of a certain configuration. For a number of the obtained compounds, the prospects of practical application are provided. In general, the current review is intended for specialists working in the field of organic synthesis and application of organochalcogen compounds. The authors declare no conflict of interests regarding the publication of this article.