Treatment of gold(III)-isocyanides [AuCl₃(CNR¹)] (R¹ = Xyl 1, Cy 2, Bu^t 3) with an equimolar amount of 5,5-dimethyl-1-pyrroline-N-oxide (4) in CH₂Cl₂ at -74 °C leads to the generation of the heterocyclic aminocarbene species [AuCl₃{C(ON^aCMe₂CH₂CH₂C^bH)=N^eR¹}(N^a-C^b)(C^b-N^e)] 8 (for R¹ = Bu^t) or gold(III) complexes cis-[AuCl₂{N^a(CMe₂CH₂CH₂C^bN^eR¹)C^d=O}(N^a=C^b)(N^e-C^d)] 9 and 10 (for R¹ = Xyl and Cy) in good isolated yields (75-87%). DFT calculations show that deprotonation of the endocyclic CH group in the carbene ligand leads to spontaneous N-O bond cleavage, and acidity of this group is a factor controlling the different chemical behavior of 1-3 depending on the nature of substituent R¹. The reaction of equimolar amounts of the aldonitrone p-TolCH=N⁺(Me)O^- (5) or the ketonitrones Ph₂C=N⁺(R²)O^- (R² = Ph 6, CH₂Ph 7) with 1-3 in CD₂Cl₂ at -70 °C in air (or under N₂) revealed the formation of the carbene complexes [AuCl₃{C(ONMeC^aH-p-Tol)=N^bR¹}(C^a-N^b)] (R¹ = Cy 11, Xyl 12, Bu^t 13), [AuCl₃{C(ONPhC^aPh₂)=N^bR¹}(C^a-N^b)] (R¹ = Cy 14, Bu^t 15), or [AuCl₃{C(ON(CH₂Ph)C^aPh₂)=N^bR¹}(C^a-N^b)] (R¹ = Cy 16, Xyl 17), as studied by ¹H NMR. The reaction of 6 with 1 and of 7 with 3 did not furnish carbene products. Compounds 8-10 were characterized by ESI-MS, IR, 1D (¹H, ¹³C{H}) and 2D (¹H,¹H-COSY, ¹H,¹³C-HSQC, ¹H,¹³C-HMBC) NMR spectroscopic techniques, and, only for 8, elemental analyses (C, H, N), while compounds 11-17 were characterized by 1D (¹H, ¹³C{H}) and 2D (¹H,¹³C-HSQC) NMR. Structures of compounds 8, 9, and 13 were additionally established by single-crystal X-ray diffraction.