Green Trends in Synthesis of Alkenyl and Alkynyl Chalcogenides

Abstract

Background: Vinylic and acetylenic chalcogenides have received considerable attention, due to the significant role of these compounds in organic synthesis as versatile building blocks, ligand chemistry, materials science, and biologically relevant processes. Furthermore, these functional groups are found in some important drugs such as (Z)-tamoxifen, which is known as an estrogen antagonist as well as antitumor fredericamycin A. Methods: Therefore, several synthetic methods have been reported in the literature for the preparation of these valuable compounds. Efficeint synthetic protocols based on the green chemistry aspects for the preparation of alkenyl and alkynyl chalcogenides involving the use of benign reaction media and alternative energy resources have been discussed in this review. These processes include examples of coupling reactions, hydrochalcogenation reactions and a variety of reactions mediated by water or recyclable and reusable catalysts. Results: It has been demonstrated that various Csp2 Y and Csp Y (Y = S, Se, Te) bond forming reactions can be successfully carried out with high selectivities and yields in an environmentally friendly fashion. Conclusion: This review focuses on the sustainable and ecofriendly synthetic processes toward alkenyl and alkynyl chalcogenides from readily available alkynes/alkenes and organochalcogens. Moreover, the potential synthetic applications and mechanistic aspects of these transformations are also discussed where appropriate. Keywords: Alkenyl chalcogenides, alkynyl chalcogenides, green reaction media, heterogeneous and homogeneous catalysts, selectivity, sustainable methods.