Ir-Catalyzed Cycloaddition of Tribenzocyclyne with Biphenylenes

We demonstrate that Ir-catalyzed C-C bond activation in biphenylenes followed by a reaction with tribenzocyclyne is a suitable method for synthesizing strained and unknown monoadducts with the tetradehydrotetrabenzo[a,c,e,i]cyclododecene scaffold ([12]annulenes). Modification of reaction conditions also furnished [12]annulene products with cis and/or trans double bonds formed by hydrogen transfer. The [9]annulene side product was formed upon the reaction of the benzyl radical with tribenzocyclyne during the Bergman cyclization. All isolated compounds were fully characterized by HRMS, NMR, and X-ray diffraction analysis.

Automated summary

We have demonstrated that C-C bond activation in biphenylenes catalyzed by iridium, followed by reaction with tribenzocyclyne, is a suitable method for synthesizing strained and unknown monoadducts. By modifying the reaction conditions, [12]annulene products with cis and/or trans double bonds formed by hydrogen transfer can also be obtained. In addition, a [9]annulene side product was formed during the reaction.