Bismuth-Catalyzed Organic Synthesis Pathways

Bismuth has emerged as an increasingly versatile catalyst in organic synthesis, combining low toxicity and environmental compatibility with potent Lewis acidity and redox flexibility. The trivalent oxidation state of bismuth enables activation of carbonyl compounds, alkenes and alkynes via coordination or oxidative pathways, while its ability to cycle between Bi(III) and Bi(I) offers opportunities for mild transfer hydrogenation and radical processes. Key applications span classical Friedel–Crafts alkylations and acylations, hydroamination of unsaturated substrates, multicomponent and cascade reactions, as well as selective reductions and oxidations. Advances in homogeneous and heterogeneous bismuth systems—ranging from soluble Bi(OTf)₃ complexes to supported bismuth oxide nanoparticles—have broadened substrate scope, improved functional‐group tolerance and facilitated enantioselective transformations. Collectively, these developments illustrate bismuth’s role as a sustainable alternative to more toxic or precious‐metal catalysts, with growing relevance in pharmaceutical synthesis, fine‐chemical manufacture and flow‐chemistry platforms.

Research from Nature Portfolio

Recent studies have demonstrated the potential of bismuth triflate as a chiral Lewis acid in enantioselective Friedel–Crafts alkylations, achieving high enantiomeric excesses under ambient conditions and enabling the synthesis of complex indole and pyrrole derivatives. Parallel work has exploited a bismuth‐mediated hydroamination protocol in which Bi(III) activates unactivated alkenes towards intramolecular nitrogen addition, providing access to pyrrolidine and piperazine cores with excellent regioselectivity. Another contribution has elucidated a novel bismuth redox cycle for transfer hydrogenation of ketones, whereby in situ generated Bi(I) species facilitate hydride transfer from secondary alcohols, affording secondary alcohols and diols in good yield without requiring external hydrogen gas.

Bismuth-Catalyzed Organic Synthesis Pathways publication trend

The graph below shows the total number of articles in bismuth-catalyzed organic synthesis pathways across all publications each year (not limited to Nature Index journals).

Technical terms

Lewis acid: A species that accepts an electron pair to activate electrophilic substrates.

Transfer hydrogenation: A catalytic process transferring hydrogen from a donor molecule to an acceptor without gaseous hydrogen.

Hydroamination: Addition of an N–H bond across a carbon–carbon multiple bond.

Enantioselective catalysis: Catalysis favouring the formation of one enantiomer over another in chiral products.

Radical cascade cyclisation: A sequence of bond‐forming events initiated by radical intermediates to construct cyclic frameworks.

Heterogeneous catalysis: Catalysis in which the catalyst exists in a different phase, often solid, from the reactants.