Arynes, chemistry preparation

Although a large number of aryne-metal complexes have been prepared and characterized, and they have an interesting chemistry of their own, that chemistry is in general quite different from the types of reactions usually associated with arynes. One might have hoped that aryne-metal complexes could act as shelf-stable storehouses for arynes, that could then be released on demand to do their usual chemistry (as in the manner, for example, of cyclobutadiene complexes), but to date this has not proved to be the case. The synthesis and chemistry of aryne-metal complexes has been reviewed, and the interested reader is also provided with a few references to work that has appeared since those reviews. ... 

While no concerted attempts to prepare selenaarynes have been reported, the chemistry of several potential precursors has been examined. The 2-lithio-3-bromo derivatives 490 and 491 react with electrophiles as expected for aryllithium reagents and show no tendency at —70°C to eliminate lithium bromide to form a 2,3-didehydroselenophene (492). Similar observations have been reported for the benzolog 493 and the possible aryne 2,3-didehydrobenzo[ft]selenophene 494. As in the corresponding sulfur and oxygen heterocycles, this unusual stability of the 2-lithio derivatives is probably related to the ability of the heteroatom to stabilize an adjacent carbanion. ... 

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