Synthesis of Functionalized 1,3,2-Benzodiazaborole Cores Using Bench-Stable Components.

The azaborine motif provides a unique opportunity to develop core isosteres by inserting B-N units in place of C═C bonds within aromatic scaffolds, creating new pseudoaromatic building blocks that retain comparable structural features. Previous synthetic routes to the 1,3,2-benzodiazaborole core have used organoboron dichlorides and boronic acids as the boron precursors. The transformation developed herein utilizes entirely bench stable starting materials, including organotrifluoroborates, enabling a wider array of substrate analogues under facile reaction conditions. Furthermore, physical, structural, and electronic properties of these compounds were explored computationally to understand the influence of the B-N replacement on the structure, aromaticity, and isosteric viability of these analogues.