Bifunctional-Phosphine-Catalyzed Sequential Annulations of Allenoates and Ketimines: Construction of Functionalized Poly-heterocycle Rings

A highly stereoselective sequential annulation reaction between γ‐substituted allenoates and ketimines was reported. By using bifunctional N‐acyl aminophosphine catalysts, poly‐heterocycle rings were obtained with high stereocontrol in good to excellent yields. The desired products have four contiguous stereogenic centers (one quaternary and three tertiary carbon centers), and only one isomer was obtained in all reactions. A highly stereoselective sequential annulation reaction between γ‐substituted allenoates and ketimines is presented. Using bifunctional N‐acyl aminophosphine catalysts, poly‐heterocycle rings were obtained in good to excellent yields. The desired products have four contiguous stereogenic centers (one quaternary and three tertiary carbon centers), and only one isomer was obtained in all reactions.