An improved synthesis of 1,1-dimethylethyl 6-cyanomethyl-2,2-dimethyl-1,3-dioxane-4-acetate, a key intermediate for atorvastatin synthesis

An improved synthesis of 1,1-dimethylethyl 6-cyanomethyl-2,2-dimethyl-1,3-dioxane-4-acetate, a key intermediate for the synthesis of an effective HMG-CoA reductase inhibitor atorvastatin, is described. The synthesis is based on the iodolactonization of hepta-1,6-dien-4-ol to 4-allyl-6-iodomethyl-1,3-dioxan-2-one, which was converted in several steps to (6-allyl-2,2-dimethyl-1,3-dioxan-4-yl)-acetonitrile. This intermediate provided (6-cyanomethyl-2,2-dimethyl-1,3-dioxan-4-yl)acetic acid either via the corresponding aldehyde or via (2,2-dimethyl-6-oxiranylmethyl-1,3-dioxan-4-yl)acetonitrile.