The highest overall yield was observed for the formation of gem-dimethyl-substituted spiroacetal 53, which may be attributed to the Thorpe-Ingold effect facilitating ring closure. Racemates are commonly employed in high-throughput screens; however, the inclusion of diastereoisomeric mixtures in compound libraries is generally avoided. We therefore explored the possibility of converging our diastereoisomeric mixtures of substituted bis-morpholine spiroacetals to single diastereomers by anomerization. Lewis acids have been used to epimerize heterocyclic acetals; 72 however, we focused on the use of Brønsted acids, pioneered by Deslongchamps on similarly substituted 6,6-spiroacetals (1,7-dioxaspiro[5.5]undecanes). Unsurprisingly, attempted anomerization of spiroacetal 52 using 3 M HCl in MeOH led to Boc deprotection. We therefore synthesized (see Supporting Information) an analogue (59) containing Cbz and Fmoc carbamate protecting groups. A 1:1 diastereoisomeric mixture of 59 was treated with 3 M HCl in MeOH. After 24 h at room temperature, the ratio had increased to 9:1. This ratio did not change over the course of one week, suggesting the reaction had reached equilibrium. It was not possible to confirm the structure of the major diastereoisomer by 1 H-NMR spectroscopy owing to extensive resonance overlap, compounded by the presence of rotamers; however, based on literature precedent, we postulate that the major diastereomer is the double anomerically stabilized spiroacetal eq-59, in which the benzyl group occupies an equatorial orientation (Scheme 9). We next explored doubly substituted bis-morpholine spiroacetal 60 (see Supporting Information). Subjecting a 3:2 diastereoisomeric mixture of 60 to 3 M HCl in MeOH at room temperature, now delivered a 19:1 ratio of products after 22 h, which did not change upon extending the reaction time. We again hypothesize 74 the major diastereomer is eq-60, which benefits from double anomeric stabilization and now two substituents adopting equatorial positions; this result suggests that in some instances (matched cases), it should be possible to access highly diastereoisomerically enriched products by anomerization.