Borole Ring Expansion Reactions with Boron Azides: A Versatile Pathway to Borylated Azaborinines

The reaction of boroles with organic azides is known to straightforwardly yield 1,2‐azaborinines, which have generated significant interest as benzene bioisosteres. We show that this powerful synthetic pattern extends to a variety of structurally and chemically diverse boron azides, including recently reported diborane(4) azides. This provides a general, powerful borylation method to expand the chemistry of 1,2‐azaborinines.