Reactivities and mechanisms in organic reactions involving activation of elemental sulfur under basic conditions

As a readily available and benign waste product of the petrochemical industry, elemental sulfur displays desirable characteristics as a raw material for new processes. Accordingly, the use of elemental sulfur as a reactant or reagent in synthetic organic chemistry receives continuous interest. The implementation of sulfur in synthetic procedures often necessitates the presence of basic or nucleophilic compounds, which are known to serve as activators, enabling a diverse range of transformations. However, the underlying mechanisms are still poorly understood, even for synthetically useful and well-established reactions that have been known for decades. While numerous reviews focus on the various types of products accessible via organic reactions involving elemental sulfur, this manuscript will put its emphasis on common mechanistic steps of these transformations, highlighting and discussing mechanistic studies and postulated pathways.