Notably, our borate ester catalyst B(OAr F )3 is less significantly inhibited by the addition of 2aminopyridine, with a 55% yield of amide being obtained even with 1 eq of 2-aminopyridine present (10 eq. with respect to catalyst). We hypothesised that 2-aminopyridine may inhibit catalysis by binding/stabilising catalytically inactive species in the solution. Treatment of 2-chlorophenylboronic acid with 2-aminopyridine led to the formation of a stable boroxine complex (Scheme 5) with an NMR spectrum consistent with the structure 36 (rather than chelated isomer 37). Calculations at the B3LYP+GD3+BJ/Def2-TZVPP/SCRF level 50 suggest this complex is 5.1 kcal mol -1 lower in free energy (DG 298 ) than the free components using chloroform as a continuum solvent. The corresponding values for complexes with benzylamine and aniline are respectively -5.0 and +1.2 kcal mol -1 . The complex between phenyl boroxine and 2-aminopyridine was successfully characterised by single crystal X-ray diffraction, confirming the hypothesised hydrogen bonding interaction between the pyridyl amine and the boroxine oxygen (Scheme 5B).