A regioselective [3 + 2] cycloaddition of benzofuranone type active olefins with allenoates catalyzed by trivalent phosphines has been developed, which provided an easy access to enriched functionalized spirocyclic benzofuranones. The reactions accommodated a number of benzofuranone type electron-deficient olefins and allenoates to give the desired 3-spirocyclopentane benzofuran-2-ones or 2-spirocyclopentane benzofuran-3-ones with moderate to excellent yields (up to 99%) and moderate to good regioselectivities (up to 11
:1).
Organic & Biomolecular Chemistry
- Information Point