β‑Selective Addition of Pyrroles to Electron-Deficient Alkenes in Both Catalytic and Stoichiometric Modes on B(C(6)F(5))(3)

To the best of our knowledge, the addition of pyrroles to electron-deficient alkenes (APEda) via electrophilic aromatic substitution (S(E)Ar) has been reported to occur exclusively at the α-position of the pyrrole without any formation, even in trace amounts, of a β-adduct, β-3. In sharp contrast to the prolonged immutable observation, we established an original S(E)Ar-based APEda (S(E)Ar-APEda) system applicable to both the catalytic and stoichiometric synthesis of β-3.