The Influence of the Quinoline Moiety on Direct Pd‐Catalyzed Arylation of Five‐Membered Heterocycles


European Journal of Organic Chemistry

Bogdan Štefane, Uroš Grošelj, Jurij Svete, Franc Požgan, Drago Kočar, Helena Brodnik Žugelj

The regioselectivity of the arylation reaction of five‐membered heterocycles bearing a quinoline directing group was studied. The transformation was strongly influenced by site position of the attached five‐membered heterocycle thus giving rise to C3‐ and/or C5‐arylated products. Herein we report a study on the reactivity of C2‐quinoline‐substituted furan, thiophene and pyrrole derivatives in palladium‐catalyzed direct C–H arylation. The regioselectivity of the reaction was strongly influenced by site position of the attached five‐membered heterocycle thus giving rise to C3‐ and/or C5‐arylated products. Furthermore, the Hammett correlation performed on 5‐substituted‐8‐(furan‐2‐yl)quinolines indicates that a marginally positive charge is building up in the rate determining transition state and thus pointing towards the electrophilic metalation‐deprotonation reaction mechanism.

Read article: Eur. J. Org. Chem., 2019, 432-441