ATS-8 — (4R,6R)-tert-Butyl-6-cyanomethyl-2,2-dimethyl-1,3-dioxane-4-acetate

ATS-8 is a chiral acetonide-protected dioxane intermediate that supplies the defined (4R,6R) stereochemistry required for Atorvastatin’s pharmacologically active diol side chain. As a late-stage chiral intermediate, its enantiomeric purity is one of the most tightly controlled quality attributes in atorvastatin API manufacturing.