A Highly Regioselective Ring-Opening Metathesis−Cross Metathesis Process Modulated by the Electronic Effects of the Cross Metathesis Partner: An Entry to Quaternary Prolines

A modulation of the regioselectivity in the ring-opening metathesis−cross metathesis (ROCM) process, originated by the electronic features of the acyclic olefin, is described. Electron-poor and electron-rich olefins showed opposing behavior giving different regioisomers. The reaction opens the way to the synthesis of interesting proline analogues incorporating a quaternary stereocenter.