Stereocontrolled Synthesis of Highly Substituted Proline Esters via [3 + 2] Cycloaddition between N-Metalated Azomethine Ylides and Nitroalkenes. Origins of the Metal Effect on the Stereochemical Outcome

1. Ayerbe, M.
2. Arrieta, A.
3. Cossío, F.P.
4. Linden, A.