Bifunctional Primary Amine‐Squaramide Catalyzed Enantioselective Intramolecular Michael Addition of Keto‐enones: A Convenient Process to the Stereocontrolled Construction of <i>trans</i>‐Dihydrobenzofuran Skeletons

Abstract

Abstract A highly diasterero‐ and enantioselective intramolecular Michael addition of keto‐enones has been realized. By using the ( R , R )‐1,2‐diphenylethane‐1,2‐diamine‐based bifunctional primary amine‐squaramide catalyst, the reaction proceeded smoothly to generate the corresponding trans ‐2,3‐disubstituted dihydrobenzofuran derivatives in excellent yields with good to excellent diastereo‐ and enantioselectivities (up to 97:3 dr , up to &gt;99 % ee ).