Diastereoselective Synthesis of 2-(Pyrrolidin-2-ylidene)-1H-indene-1,3-diones via 1,3-Dipolar Cycloaddition of H-Bond-Assisted Azomethine Ylides with Chalcones

Abstract The diastereoselective synthesis of NH-unprotected pyrrolidin-2-ylidene derivatives was accomplished via 1,3-dipolar cycloaddition of H-bond-assisted azomethine ylides with chalcones. This process resulted in the formation of three stereogenic centers, exhibiting excellent diastereoselectivity. The effectiveness of this approach was illustrated through a gram-scale experiment, and the structure of the final product was confirmed by single-crystal X-ray analysis.