Reaction of arynes with vinylogous amides: nucleophilic addition to the ortho-quinodimethide intermediate.

The reaction of arynes with vinylogous amides containing no free N–H bonds proceeds in a [2 + 2] cycloaddition fashion at ambient temperature. The electronic properties of the vinylogous amides allow for the cycloadducts undergoing a facile ring-opening process, leading to electronically biased ortho-quinodimethide intermediates. Subsequent nucleophilic addition with alcohols affords 2-substituted benzaldehydes or ketones.