The Mn(OAc)-promoted oxidative phosphonylation of N,N-dimethylenaminones with H-phosphonates, involving a chemo- and regioselective C-C bond cleavage and C-P bond formation in one step, provided successfully functionalized β-ketophosphonates under mild reaction conditions. Oxidative C-H/P-H cross-coupling reactions via C-C(C═O) bond cleavage and mechanistic studies are conducted preliminarily, and a possible mechanism is proposed. This novel method proceeds in good to excellent yields, shows operational simplicity, broad substrate scope, and large-scale preparation.

A concise and efficient route for the synthesis of highly substituted imidazopyrroloquinoline derivatives by simply refluxing a reaction mixture of different types of isatins and heterocyclic ketene aminals (HKAs) by acetic acid was developed. This method is suitable for combinatorial and parallel syntheses in drug discovery; consequently, a library of highly substituted imidazopyrroloquinoline derivatives was rapidly constructed using the present protocol.

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Divergent cascade syntheses constitute a highly attractive and challenging area in synthetic chemistry, and can exhibit unexpected chemoselectivity. Herein, a Brønsted acid-controlled protocol is described for the efficient catalysis of two different reactions, namely acylation cascade- and [1+2+3]-type cyclization of enaminones and isatins for the concise synthesis of highly functionalized pyrrolo[3,4-c]quinolin-1-ones and spirooxindoles in the presence of carboxylic acids and KHSO4, respectively. The observed chemoselectivity was reasonably explained by trapping the intermediate α,β-unsaturated 2-oxindoles, and the source of the hydroxyl group, carbocation intermediate, and amination reaction were also evaluated.

An unprecedented method for the construction of thiazole-2-thiones via an oxidative cascade cyclization strategy is described. The novel protocol involves the simultaneous formation of two CS bonds and a CS bond on the structure of enaminones in a single operation through a cascade of C­(sp2)H/C­(sp3)H bond sulfurations and C­(sp3)–H bond thiocarbonylation. This transformation allows for the efficient synthesis of thiazole-2-thiones with broad tolerance in moderate to excellent yields from simple enaminones with elemental sulfur.

A direct Csp3–H bond oxidative thioesterification of methyl ketones with aromatic thiols/disulfides promoted by TBAI/K2S2O8 has been developed. The reaction provides successfully a simple and efficient method for the synthesis of functionalized α-ketothioesters of aromatic thiols. This practical methodology exhibits readily available starting materials, large-scale applicability, synthetic application, and broad functional group tolerance. A possible mechanism for the transformation is proposed.

Enaminones are gaining increasing interest because of their unique properties and their importance in organic synthesis as versatile building blocks. N,N-Dimethyl enaminones offer a better leaving group (a dimethylamine group) than other enaminones, and allow further elaboration via a range of facile chemical transformations. Over the past five years, there have been an increasing number of reports describing the synthetic applications of N,N-dimethyl enaminones. This review provides a comprehensive overview on the synthetic applications of N,N-dimethyl enaminones that have been reported since 2016.1 Introduction2 Direct C(sp2)–H α-Functionalization2.1 Synthesis of α-Sulfenylated N,N-Dimethyl Enaminones2.2 Synthesis of α-Thiocyanated N,N-Dimethyl Enaminones2.3 Synthesis of α-Acyloxylated N,N-Dimethyl Enaminones3 Functionalization Reactions via C=C Double Bond Cleavage3.1 Synthesis of Functionalized Methyl Ketones3.2 Synthesis of α-Ketoamides, α-Ketoesters and 1,2-Diketones3.3 Synthesis of N-Sulfonyl Amidines4 Construction of All-Carbon Aromatic Scaffolds4.1 Synthesis of Benzaldehydes4.2 Synthesis of the Naphthalenes5 Construction of Heterocyclic Scaffolds5.1 Synthesis of Five-Membered Heterocycles5.2 Synthesis of Six-Membered Heterocycles5.3 Synthesis of Quinolines 5.4 Synthesis of Functionalized Chromones5.5 Synthesis of Other Fused Polycyclic Heterocycles6 Conclusions and Perspectives

A novel and facile Cu-catalyzed addition/cyclization cascade of o-cyanoarylacrylamide was developed. The process exhibits significant functional group tolerance, and provides an efficient and straightforward pathway for the synthesis of various phosphonylated quinoline-2,4(1H,3H)-diones.