Efficient Access to Arylated Aza‐ullazines by Regioselective Functionalization of their Pyridine Ring by H−Li Exchange and Electrophilic Substitution. Issue 22 (15th June 2021) - Ibrahim, Dhuaou
Abstract: The regioselective functionalization of aza‐ullazines has been successfully realized for the first time by either metalation using BuLi‐containing aggregates (BuLi‐LiDMAE) or electrophilic substitution. Mono and di‐bromo‐derivatives were obtained in good to excellent yields and further successfully converted into aryl and alkynyl azaullazine derivatives by Suzuki and Sonogashira cross‐coupling reactions. Abstract : First functionalization of azaullazine heterocycle is reported. Regioselective metalations and electrophilic substitutions allow to introduce valuable halogen atoms at the alpha position of the peripheral nitrogen, the latter being subsequently engaged in Suzuki or Sonogashira arylation through efficient Pd‐promoted cross‐coupling reactions.