Dearomatisation approaches to spirocyclic dienones via the electrophilic activation of alkynes.

Two complementary dearomatising spirocyclisation protocols to generate spirocyclic dienones from anisole and phenol-tethered ynones are described, each proceeding via electrophilic alkyne activation. The first approach focuses on the spirocyclisation of para-substituted anisoles using either SnCl·2HO or Cu(OTf). The second approach, which enables the spirocyclisation of both ortho- and para-substituted phenols, uses silica-supported AgNO to generate similar scaffolds with much greater efficiency. Initial asymmetric studies are also outlined.