Phosphorus(III) reagents in the chemistry of cyclothiazenes

Cyclic sulphur-nitrogen compounds which have been known for over a century are novel examples of inorganic ring systems due to their variety in structure, bonding and reactivity. Especially in the last two decades, the use of different types of trivalent phosphorus reagents have contributed significantly for developing the chemistry of cyclothiazenes. These aspects are highlighted in this article.