Chemistry of Gold(III) with a Pyridine-Oxaziridine Ligand: Competition between C-O and N-O bond Activation

The oxaziridine derivative 2-t-butyl-3-(2-pyridinyl)oxaziridine reacted with Na[AuCl₄ ].2H₂ O to give, after recrystallization from a solvent mixture containing methanol, a mixture of gold(III) complexes which were characterized crystallographically as the amide complex [AuCl₂ {κ² -N,N'-2-C₅ H₄ NC(=O)N(t-Bu)] and the aldolate complex [AuCl₂ {κ² -N,O-2-C₅ H₄ NCH(OMe)O)]. It is suggested that these products arise after initial O-N or C-N bond cleavage respectively of the strained oxaziridine ring, after coordination to the gold(III) center. Monitoring of reactions by NMR spectroscopy showed that O-N bond cleavage of the oxaziridine ring was favoured in the presence of a protic solvent.