Ipso-Nitration of Boronic Esters Enabled by Ferric Nitrate Nonahydrate (Fe(NO₃)₃·9H₂O) in HFIP

We describe in this work an operationally facile and generally applicable ipso-nitration of boronic esters by Fe(NO₃)₃·9H₂O in hexafluoroisopropanol (HFIP), allowing us fast access to various nitroarenes that are currently difficult to obtain via traditional electrophilic C–H nitrations. In contrast to previous deborylative ipso-nitrations, this new protocol utilized less reactive and more stable organoboron reagents and therefore had significantly improved substrate scope and functional group tolerance, which was exemplified in the late-stage ipso-nitration of various natural products, pharmaceuticals, and biologically active molecules.