Enantio- and Diastereoselective Construction of Contiguous Tetrasubstituted Chiral Carbons in Organocatalytic Oxadecalin Synthesis

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, both cis - and trans -decalin-type scaffolds were synthesized with good to excellent stereoselectivities, and a range of functional groups accumulated on the chiral quaternary carbon moieties of the trans -oxadecalin derivatives.