text: The chemistry of stable carbenes has not been fully explored. However, Enders et al.
  have performed a range of organic reactions involving a triazol-5-ylidene. These reactions are outlined below and may be considered as a model for other carbenes.
  These carbenes tend to behave in a nucleophilic fashion (e and f), performing insertion reactions (b), addition reactions (c), [2+1] cycloadditions (d, g and h), [4+1] cycloadditions (a) as well as simple deprotonations. The insertion reactions (b) probably proceed via deprotonation, resulting in the generation of a nucleophile (XR) which can attack the generated salt giving the impression of a H–X insertion.
  The reported stable isothiazole carbene (2b) derived from an isothiazolium perchlorate (1) was questioned. The researchers were only able to isolate 2-imino-2H-thiete (4). The intermediate 3 was proposed through a rearrangement reaction. The carbene 2b is no longer considered as stable.