B(C₆F₅)₃‑Catalyzed β‑Functionalization of Pyrrolidines Using Isatins via Borrowing Hydrogen: Divergent Access to Substituted Pyrrolidines and Pyrroles

We report herein a B­(C₆F₅)₃-catalyzed redox-neutral β-functionalization of pyrrolidines with isatins. Under transition-metal- and oxidant-free conditions at ambient temperature, a series of pyrrolidines bearing a functionalized exocyclic alkene are accessed in high efficiency through a borrowing hydrogen process. A simple switch to higher reaction temperature in a one-pot procedure also provides access to a diverse array of C(3)-functionalized pyrroles while liberating water and hydrogen gas as the only byproducts.