Although this strategy proved efficient, it only allows for the substitution of fluorides on pyridine-like electrophiles. Other electron-deficient aryls possessing cyano, nitro or ester groups failed to generate the desired N-arylated azetidines, consequently limiting the scope of the reaction. Therefore, we looked for an alternative that would broaden the possibilities for C-N bond formation and oriented ourselves towards Pdcatalyzed transformations. Buchwald-Hartwig coupling reactions have witnessed tremendous improvements since the pioneering studies of those who gave their names to the transformation. Many examples from drug discovery programs have been reported on the coupling of secondary amines, even including some azetidines. Two starting materials were tested for reaction optimizations (Table ), azetidinium-oxalate salt , following Carreira's procedure on spiro compounds, and free azetidine ( ), isolated through basic workup, using p-bromoanisole as coupling partner. While catalytic systems such as Pd2(dba)3/BINAP or Pd(OAc)2/Xantphos (entries 1-3) only yielded coupling product 10 in 4 to 17% from the oxalate salt 8 (with either KOt-Bu or NaOt-Bu as the base), it was isolated in 22 to 24% yield when switching to xPhosPdG3/Brettphos and RuPhosPdG3/RuPhos (entries 4 and 5), respectively. Although full consumption of the coupling partner was observed in most cases, and despite further optimization efforts using 8, no better yield than 24% could be obtained, probably because of undesired ring-opening side-reactions. However, when employing the free azetidine 9 (entries 6-8), yields were increased to 82% in the presence of xPhosPdG3/Brettphos as the catalytic system. If lower temperatures resulted in lower yields, decreasing the catalyst loading to 1% did not show any negative influence on the efficiency of the coupling.