The efficiency of a chemical synthesis can be nowadays measured, not only by parameters like selectivity and overall yield, but also by its raw material, time, human resources and energy requirements, as well as the toxicity and hazard of the chemicals and the protocols involved. The development of multicomponent reactions (MCRs) in the presence of task-specific ionic liquids (ILs), used not only as environmentally benign reaction media, but also as catalysts, is a new approach that meet with the requirements of sustainable chemistry. The aim of this tutorial review is to highlight the synergistic effect of the combined use of MCRs and ILs for the development of new eco-compatible methodologies for heterocyclic chemistry.

Although isocyanide‐based multicomponent reactions (MCRs), introduced in 1921 by Passerini, largely predominate nowadays in the construction of widely diverse heterocycles, one of the first substrate classes involved in a MCR was that of 1,3‐dicarbonyl derivatives, with Hantzsch’s dihydropyridine synthesis appearing as early as 1882. The aim of this microreview is to present an overview of the great synthetic potential of MCRs involving the specific reactivity of easily accessible 1,3‐dicarbonyl derivatives and to stress their more recent utilisation for the development of new and useful methodologies valuable for the selective construction of highly functionalised small organic molecules of high synthetic and biological value. After a short general introduction, we present chronologically the different methodologies developed on the bases of the reactivity of 1,3‐dicarbonyl systems towards many other substrates involved in a variety of synthetic pathways, including Knoevenagel condensations, Michael and Mannich reactions, cyclodehydrations, electrocyclisations, cycloadditions and metal‐promoted transformations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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For the first time, enantiomerically enriched atropoisomeric furans have been accessed using a central-to-axial chirality conversion strategy. Hence, oxidation of the enantioenriched dihydrofuran precursors gave rise to axially chiral furans with high enantiopurities accounting from excellent conversion percentages (cp) in most cases.

Three is a lucky number: An enantioselective transformation of allylic alcohols into β-chiral saturated alcohols has been developed by combining two distinct metal- and organocatalyzed catalytic cycles. This waste-free triple cascade process merges an iron-catalyzed borrowing-hydrogen step with an aminocatalyzed nucleophilic addition reaction.

Suitably substituted enantioenriched 4-aryl-1,4-dihydro-pyridines prepared by an organocatalytic enantioselective Michael addition were oxidized with MnO2 into axially chiral 4-arylpyridines with central-to-axial chirality conversion. Moderate to complete percentages (cp) were observed, and a model for the conversion of chirality is discussed.

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International audienceSynthetic applications of cyclobutanones other than ring expansion and fragmentation reactions are rare. Herein, highly efficient diastereo- and enantioselective organocatalytic Michael additions of 2-substituted cyclobutanone derivatives to nitroalkenes are reported allowing the stereocontrolled creation of " all-carbon " quaternary centers. The approach relies on both the use of Brønsted base/hydrogen-bond donor bifunctional organocatalysts, and importantly, the specific stabilization and activation of cyclobutanone with a secondary amide moiety. The reaction was found to nicely accommodate a broad scope of substrates, allowing the control of up to three contiguous stereogenic centers. This work has opened new synthetic opportunities