Arynes double bond insertion/nucleophilic addition with vinylogous amides and carbodiimides

Arynes are shown to insert into some C═X double bonds, leading to benzannulated four-membered rings. The strain of these rings allow for a ready, spontaneous opening to afford o-quinomethide analogues. Subsequent nucleophilic addition re-aromatizes the intermediates to achieve ortho-difunctionalization of arynes. In this report, we describe the aryne insertion into the C═C double bonds of vinylogous amides and the C═N double bonds of carbodiimides. The correlation and comparison with aryne single bond insertion chemistry will be discussed. Computational studies for the ring-opening step, as well as the nature of the o-quinomethide intermediates, will also be discussed.