Abstract
The Account describes recent advances, from the authors’ laboratories, in the synthesis of diverse libraries of small-molecule building blocks employing ionic liquids (ILs). The ability of ILs to act as catalysts/promoters/solvents for electrophilic and onium ion chemistry, as well as in metal-mediated cross-coupling reactions, and the potential to sequence/hyphenate these methods, have opened up new opportunities for facile assembly of functional small molecules with increased complexity from readily available precursors. While Brønsted acidic IL/IL solvent mixtures are suitable media for carbocation and onium ion chemistry, piperidine-appended IL/IL solvent mixtures can successfully catalyze a variety of base-catalyzed reactions. Several widely practiced transformations including ‘name reactions’ were adapted and performed efficiently in ILs.
1 Introduction
2 Aryldiazonium Salts and Aryltriazenes as Coupling Partners in Metal-Mediated C–C Cross-Coupling Reactions in ILs
3 Expanding the Scope of Metal-Mediated Cross-Coupling Reactions in ILs
4 Application of ILs in Synthesis and Functionalization of Heterocycles
5 Expanding the Scope of Amide Synthesis in ILs
6 Generation and Chemistry of ‘Tamed’ Propargylic Cations in ILs
7 Newer Nitration Methods for Arenes and Heteroarenes in ILs
8 Halofunctionalization in ILs
9 ‘Name Reactions’and Other Widely Practiced Synthetic Transformations in ILs
9.1 The Biginelli Reaction
9.2 Nitrile Synthesis by the Schmidt Reaction
9.3 Rupe Rearrangement
9.4 Synthesis of 1,3-Dioxanes via Prins Reaction in [BMIM(SO3H)][OTf]
9.5 Synthesis of Cyclopropanes and Oxiranes by the Corey–Chaykovsky (CC) Reaction
10 Conclusions and Closing Remarks
Key words
acidic and basic ionic liquids - aryldiazonium and aryltriazene - cross-coupling - heterocyclic chemistry - sequential/hyphenated reactions
