C-H FUNCTIONALIZATION IN THE SYNTHESIS OF CARBORANE-BASED POLYAZAHATEROCYCLIC HYDROCARBONS

Among the versatile organic fluorophores, special attention is known to be paid to photoactive organoboron compounds, in particular heterocyclic derivatives of carborane. According to numerous studies, the ortho-carborane scaffold is considered to be an “element-block” for preparing solid state luminescent materials due to its excellent suppression of aggregation-caused quenching (ACQ). Carborane-based materials also currently find an application in catalysis, medicine, supramolecular chemistry and photovoltaics.The research was financially supported by the Russian Science Foundation (Project no. 20-43-01004), a bilateral Russian Science Foundation (RSF) – Fund for Scientific Research Flanders (FWO) project, and the Francqui Foundation

Palladium-Catalyzed Migratory Insertion of Isocyanides: An Emerging Platform in Cross-Coupling Chemistry

Isocyanides have been important building blocks in organic synthesis since the discovery of the Ugi reaction and related isocyanide-based multicomponent reactions. In the past decade isocyanides have found a new application as versatile

Synthesis of 4-aminoquinolines by aerobic oxidative palladium-catalyzed double C-H activation and isocyanide insertion

An unprecedented aerobic oxidative Pd-catalyzed imidoylative coupling of two C-H fragments furnishing medicinally valuable 4-aminoquinolines is reported. Optimization studies are described and several analogs were successfully prepared. © 2013 Springer Science+Business Media New York

Palladium-Catalyzed Synthesis of 2-Aminobenzoxazinones by Aerobic Oxidative Coupling of Anthranilic Acids and Isocyanides

Isocyanides have emerged as valuable

Transition metal-catalysed carbene- and nitrene transfer to carbon monoxide and isocyanides

Transition metal-catalysed carbene- and nitrene transfer to the C1-building blocks carbon monoxide and isocyanides provides heteroallenes (i.e. ketenes, isocyanates, ketenimines and carbodiimides). These are versatile and reactive compounds allowing in situ transformation towards numerous functional groups and organic compounds, including heterocycles. Both one-pot and tandem processes have been developed providing valuable synthetic methods for the organic chemistry toolbox. This review discusses all known transition metal-catalysed carbene- and nitrene transfer reactions towards carbon monoxide and isocyanides and in situ transformation of the heteroallenes hereby obtained, with a special focus on the general mechanistic considerations

Multicomponent Synthesis of 4-Aminophthalazin-1(2H)-ones by Palladium-Catalyzed Isocyanide Insertion

4-Aminophthalazin-1(2H)-ones (APOs) are underexplored heterocyclic compounds with promising and diverse biological activities. The classical synthesis of these compounds is tedious and does not allow the regioselective introduction of substituents. Here, we present our full studies on the Pd-catalyzed cross-coupling of substituted o-(pseudo)halobenzoates and hydrazines with isocyanide insertion allowing straightforward access to diversely substituted APOs. We illustrate the advantages of this method compared to other approaches and describe solutions for the limitations we encountered. In addition, we have developed efficient diversifications of this heterocyclic scaffold that allow access to more diverse APOs as well as novel heterocyclic scaffolds. © 2013 American Chemical Society

Synthesis of Heterocycles via Aerobic Ni-Catalyzed Imidoylation of Aromatic 1,2-Bis-nucleophiles with Isocyanides

o-Phenylene N-substituted iminocarbonates have been obtained by aerobic Ni-catalyzed reaction of readily available catechols and isocyanides. The choice of oxidant and absence of base proved crucial to avoid competitive catechol oxidation into (semi)quinone, leading to degradation. The developed protocol is generally applicable on other oxidation-sensitive aromatic 1,2-bisnucleophiles, generating a variety of important bicyclic heterocycles from readily available building blocks, hitherto only accessible via aerobic noble metal catalysis. Experimental studies suggest involvement of a Ni (H) -catecholate complex, which has been supported by density functional theory of the catalytic cycle. o-Phenylene N-substituted iminocarbonates demonstrated to be interesting platform molecules providing access to dialkyl N-substituted iminocarbonates, dialkyl N-substituted dithioiminocarbonates, and N,N',N ''-trialkyl guanidines via reaction with respectively alcohols, thiols, and amines. The catechol, which is concomitantly produced as a byproduct in these substitution reactions, can be recycled. 'When 4-propylcatechol, accessible from pine and clove tree feedstock, is applied, the leaving group is also biorenewable

Palladium-Catalyzed Synthesis of 4-Aminophthalazin-1(2H)-ones by Isocyanide Insertion

Palladium-catalyzed cross-coupling of a wide range of substituted o-(pseudo)halobenzoates and hydrazines with isocyanide insertion followed by lactamization efficiently affords 4-aminophthalazin-1(2H)-ones that are difficult to obtain regioselectively by classical methods