An Efficient Approach to Azolyl-Substituted Steroids through Copper-Catalyzed Ullmann C-N Coupling

Copper-catalyzed deacetonative Sonogashira coupling

A convenient Pd- and phosphine-free protocol for assembling internal alkynes from tertiary propargyl alcohols and (het)aryl halides has been developed. The proposed tandem approach includes the base-promoted retro-Favorskii fragmentation followed by Cu-catalyzed C(sp)-C(sp²) cross-coupling. The use of inexpensive reagents (e.g. a catalyst, additives, a base, and a solvent) and good functional group tolerance make the procedure practical and cost-effective. The synthetic utility of the method was demonstrated by a smooth alkynylation of vinyl iodides derived from natural steroidal hormones.

Recent achievements in copper catalysis for C–N bond formation

A mini-review describes the development of the catalysis by Cu(I) complexes aimed at the formation of C–N bond at the Lomonosov MSU during 2010s. The main approach employs the amination of aryl and heteroaryl halides with the amines and polyamines, in this direction a great versatility of starting compounds was achieved: adamantane-containing amines, linear diamines, oxadiamines and polyamines, various aryl iodides and bromides, derivatives of pyridine, and quinoline were used for this purpose. In more peculiar cases, the copper catalysis was used for steroids transformations, including vinylation of azoles, wide-spread “click” reactions for the conjugate syntheses, and successful heterogenezation of the copper catalysts were also undertaken.

An Acid-Catalyzed Addition and Dehydration Sequence for the Synthesis of Heteroarylated Steroidal Dienes

Additions of heteroarenes to hormone steroids containing an α,β-unsaturated ketone are reported. Additions of a range of electron-rich heteroarene nucleophiles, including indoles, a pyrrole, and a thiophene, to a variety of commercially available steroids and subsequent dehydration formed 3-heteroarylated steroidal dienes in up to 93% yield. This atom-economical reaction sequence occurs under mild reaction conditions in the presence of catalytic bismuth triflate.

New trends in the cross-coupling and other catalytic reactions

A mini-review covers the latest achievements in the field of metal-mediated cross-coupling reactions among which are palladium-catalyzed Heck, Suzuki, cyanation and amination reactions. The aspects of the application of Pd nanoparticles (PdNPs) are discussed. The possibilities of the applications of Cu(I)-catalyzed reactions are described. Special emphasis is made on the synthesis of polymacrocyclic compounds like porphyrin dyads and triads, polyazacryptands bearing fluorophore groups using catalytic methods. The application of Pd-catalyzed CH-activation reactions for porphyrin modifications is described, the use of Lewis acids catalysis and organocatalysis for enantioselective C–C bond formation is considered with the emphasis on the application of immobilized organocatalyst.

Alkynylation of steroids via Pd-free Sonogashira coupling

A new biligand catalytic system was applied for the Pd-free Sonogashira syntheses of valuable steroidal enynes.

Reusable ionic liquid-catalyzed oxidative coupling of azoles and benzylic compounds via sp3 C–N bond formation under metal-free conditions

The heterocyclic ionic liquid-catalyzed direct oxidative amination of benzylic sp³ C–H bonds via intermolecular sp³ C–N bond formation for the synthesis of N-alkylated azoles under metal-free conditions is reported for the first time.