The organocatalytic enantio- and diastereoselective cycloetherification of 1,3-cyclohexanedione-bearing enones involving the in situ generation of chiral cyanohydrins was developed. This transformation offers the first catalytic asymmetric approach to oxadecalin derivatives containing contiguous tetrasubstituted chiral carbons at the bridge heads of the fused ring systems. Depending on substituents