Soft enolization conditions are revealed to be markedly better than the typically applied hard enolization protocols for regioselective enoxysilane formation from unsymmetrical 3-substituted cycloalkanones. Five-, six-, and seven-membered cycloalkanones each with 3-methyl, 3-isopropyl, or 3-phenyl substituents were investigated, and in all but one case, regioselectivities were ≥11:1 for enolization away from the substituent. These results are complementary to the regiospecific enoxysilane formation derived from cycloalkenone conjugate addition/enolate silylation.

An anionic oxy-Cope/transannular Michael addition cascade converts a spirocyclic architecture-readily available by Diels-Alder cycloaddition-into the hydrophenalene carbon skeleton of the pseudopterosin aglycones. Oxidation of the resulting cyclohexenone ring to the phenol that is characteristic of the targets completes a short formal synthesis.