Straightforward Formation of Borirenes from Boroles and Dialkynes

Abstract

We report a selective one-step synthesis of perarylated borirenes by reaction of antiaromatic boroles with 1,4-diarylbuta-1,3-diynes. Mechanistic studies, both experimental and computational, reveal key intermediates, including boranorbornadiene and 7-borabicyclo[4.1.0]heptadiene species, which are all in equilibrium with each other, ultimately leading to borirene formation by migration of the boranediyl bridge from the cyclohexadiene ring to the remaining exocyclic alkyne residue.