We next aimed to force the spirocyclohexyl moieties into closed conformations by further increasing the steric pressure through additional α-functionalization of ketoamine 4. However, this highly sterically hindered substrate proved unreactive towards further alkylation. ‡ Conversely, starting from ketoamine 3, two methylene substituents were directly incorporated through condensation with formaldehyde (Scheme 1). Although dienone 6 could be isolated, it polymerized in a matter of hours. Thus, it was immediately subjected to hydrogenation to afford dimethyl spirocyclohexyl ketoamine 7 in excellent yield as a mixture of diastereomers (dr 1:1). Subsequent oxidation with m-CPBA resulted in two diastereomers of dimethylated nitroxide 8, which was recrystallized to enable structural investigation by X-ray crystallography. We obtained a solid-state structure for the trans-diastereomer of 8, where the nitroxide ring adopts a chair conformation with one methyl substituent in an axial and the other in an equatorial orientation. The equatorial methyl group induces a conformational change of the proximal spirocyclohexyl moiety, resulting in a semi-open arrangement.