Reversal of enantioselective Friedel–Crafts C3-alkylation of pyrrole by slightly tuning the amide units of N,N′-dioxide ligands.

Chiral Ni(ii)-complexes of N,N′-dioxides show high catalytic activity and enantioselectivity in catalysing the asymmetric Friedel–Crafts C3-alkylation of 2,5-dimethyl pyrrole to β,γ-unsaturated α-ketoesters. A dramatic reversal of enantioselectivity is realized with ligands derived from the same type of chiral source of l-ramipril, by slightly tuning the amide units. [ABSTRACT FROM AUTHOR]