Five-Membered Hetarynes

The most recent review is by Kauffmann and Wirthwein in 1971 but intentionally slights five-membered hetarynes with one heteroatom in favor of their six-membered homologs. With the exception of Hoffmann s classic monograph on arynes in 1967, reviews devoted to general aryne chemistry " tend to neglect hetarynes. Considering the recent activity in this field it seems appropriate to review five-membered hetarynes at this time both as a summary of past research and as a stimulus to future research in this area. An attempt has been made to cover all pertinent literature and unpublished observations available to the author as of December 1981. ... 

As will be described in Section III investigations of the existence of five-membered hetarynes have relied heavily on analogies to the chemistry of the well-authenticated six-membered carbocyclic arynes. It will therefore be the purpose of this section to briefly review and update those aspects of aryne chemistry which have played an important role in this regard. For a more complete coverage of aryne chemistry the reader is referred to the several reviews previously cited and especially to the excellent monograph by Hoffmann. ... 

Five-Membered Hetarynes 381 TABLE 2. Generation of Arynes by Loss of Nitrogen from 0-C5H4XY (41) ... 

---