Catalyst-Controlled Divergent Annulation Reactions of Allenoates and Fully Substituted 1,3-Indandione Derived Electron-Deficient Alkenes

High Resolution Image Download MS PowerPoint Slide Two catalyst-controlled, regiodivergent annulation protocols for allenoates with fully substituted 1,3-indandione derived electron-deficient alkenes have been developed, furnishing a series of spiroindane-1,3-diones and 3,4-dihydro-2 H -pyran derivatives in high yields. Plausible mechanistic pathways for both annulation reactions are proposed: spiroindane-1,3-diones are obtained via a [3 + 2] annulation, while 3,4-dihydro-2 H -pyran derivatives arise from a [4 + 2] annulation.