Search

In this feature article, a general perspective of the research program aimed towards the preparation of polycyclic heterocycles by the means of enantioselective organocatalytic multicomponent reactions is presented. Guidelines for reaction design, including the selection of substrates and organocatalysts are discussed. For all transformations, scope and limitations are presented, along with post-functionalization to afford diversified heterocyclic scaffolds. 1 Introduction 2 Type I Products: 1,4,5,6-Tetrahydropyridines 3 Type II Products: 1,2,3,4-Tetrahydropyridines 4 Type III Products: Bridged Perhydropyridines 5 Conclusion and Perspective

International audience; Enamine activation of alpha-branched beta-ketocarbonyl compounds is actually possible, very efficient, and highly enantioselective with a bifunctional primary amine/tertiary ammonium triflate salt catalyst. This covalent HOMO activation mode competes with existing strategies for the enantioselective activation of beta-ketocarbonyls and their analogues.

International audience; The results on the multicomponent reaction between cyclic β-keto esters, enals, and simple primary aliphatic amines are reported. In thermal conditions in the presence of 4 Å molecular sieves, two different¬ families of heterocyclic products (aminobicyclo[3.3.1]nonanones or cycloalka[b]piperidines) were obtained depending on the presence of a substituent in the α-position of the aldehyde. Moreover, preliminary results on the possibility to obtain these two bicyclic cores from the very same starting materials by introducing organocatalysts with different activation modes in the reaction are presented.

In the context of sustainable chemistry, because of economic and ecological increasing pressure, domino multicomponent reactions (MCRs) constitute a central academic and industrial investigation domain in diversity-oriented synthesis of functionalized heterocycles. Although isocyanide-based MCRs generally predominate nowadays, the use of 1,3-dicarbonyls as substrates, proposed as early as 1882 by Hantzsch, proved to be highly efficient, but have been relatively unexplored until recently. In the last few years, such transformations received a growing attention as new useful methodologies valuable for the selective direct access to highly functionalized small organic molecules of primary synthetic and biological value. This review focuses on the more significant recent developments on the use of β-diketo building blocks for MCRs published in the last 5 years.