A practical, efficient synthesis of 1,1-dioxo-hexahydro-1λ6-thiopyran-4-carbaldehyde

A practical, efficient, and scalable procedure for the preparation of 1,1-dioxo-hexahydro-1 lambda(6)-thiopyran-4-carbaldehyde is reported. Synthesis of this aldehyde was complicated by high aqueous solubility of the product and the intermediates. The isolation and purification of the aldehyde was accomplished by conversion to the crystalline bisulfite adduct.