Arynoid reactions

Wittig s classic synthesis of triptycene presumably involved 2-fluorophenylmagnesium bromide as an intermediate [1]  

More recently, an ingenious sequence of metal-halogen exchange and elimination reactions has been used to prepare terphenyls from 2,6- 

As alternatives to o-halogenoarylmagnesium halides, o-phenyl-sulfonylarylmagnesium halides have been used as precursors to arynes, including 3-pyridyne [5]  

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Carbene precursors such as a-halogenoalkylmagnesium compounds and aryne precursors such as o-halogenoarylmagnesium compounds are on the whole less readily accessible than the corresponding organolithium compounds, and more thermally stable, so that carbenoid and arynoid reactions based on the organomagnesium intermediates are much less used [1]. ... 

Carbenoid and Arynoid Reactions of Organomagnesium Compounds, Pages 181-184... 

It is known that benzenediazonium-2-carboxylate decomposes to give benzyne via the zwitter-ion (128) 161>. We therefore checked that benzyne is involved in our reactions by carrying out reactions with cinnamaldehyde using benzyne generated from benzothiadiazole-1,1-dioxide 162), diphenyhodonium-2-carboxylate i 3,164)( weil as fr0m anthranilic acid165). Flavene was isolated from each reaction and hence our reactions do involve aiynes and are not arynoid 13 8). 

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