Pyrazolidinones with a tetrahydroisoquinoline core are obtained with excellent diastereocontrol and high enantioselectivity. Theoretical studies give insight on the reaction mechanism.

Stereoselective Lewis Base Catalyzed Formal 1,3-Dipolar Cycloaddition of Azomethine Imines with Mixed Anhydrides. -Azomethine imines generated in situ from (II) react with esters generated in situ from 2-phenylacetic acid derivatives (I) and benzoyl chloride in a dipolar cycloaddition reaction to afford tricyclic heterocycles of type (III) or (VI) with high diastereoselectivity and enantioselectivity. The mechanism of the reaction is studied by DFT theoretical calculations. The N-N bond of the products can be cleaved as shown by the formation of (IV). -(HESPING, L.; BISWAS, A.; DANILIUC, C. G.; MUECK-LICHTENFELD*, C.; STUDER, A.; Chem. Sci. 6 (2015) 2, 1252-1257, http://dx.