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The marriage of heterocyclic compounds with ferrocene has proven to be an extremely fruitful field of research. In fact, in the last years, several ferrocene‐embedded heterocyclic compounds have been reported. In some cases, the synergistic combination of the properties of the heterocyclic and metallacyclic motifs provides to the fused systems interesting applications. This Review summarizes the major advances in the synthesis of ferrocene‐fused nitrogen heterocyclic compounds and their applications, particularly in asymmetric catalysis. [ABSTRACT FROM AUTHOR]

The reaction of propargyl esters with alkynylsilanes under gold catalysis provides vinylallene derivatives through consecutive [1,2]‐acyloxy/[1,2]‐silyl rearrangements. Good yields, full atom‐economy, broad substrate scope, easy scale‐up and low catalyst loadings are salient features of this novel transformation. Density Functional Theory (DFT) calculations suggest a reaction mechanism involving initial [1,2]‐acyloxy rearrangement to generate a gold vinylcarbene intermediate which upon regioselective attack of the alkynylsilane affords a vinyl cation which undergoes a type II‐dyotropic rearrangement involving the silyl group and the metal fragment. Preliminary results on the enantioselective version of this transformation are also disclosed. [ABSTRACT FROM AUTHOR]

The Lewis (or Brønsted) acid‐catalyzed reaction of 2‐aryl‐N‐sulfonyl aziridines with ferrocene and ruthenocene provided new amino‐functionalized metallocene derivatives arising from a regioselective ring opening of the aziridine. The functionalized metallocene derivatives available by this methodology are suitable precursors for the stereoselective synthesis of metallocene analogues of the relevant tetrahydroisoquinoline motif by a Pictet‐Spengler type reaction. These isoquinoline analogues are also accessible by a TfOH‐catalyzed three‐component reaction of 2‐aryl‐N‐sulfonyl aziridines, ferrocene (or ruthenocene) and formaldehyde. [ABSTRACT FROM AUTHOR]

The TfOH-catalyzed reaction of aryl-substituted donor--acceptor cyclopropane derivatives with ferrocene provided new functionalized ferrocene derivatives. This process exhibited a reasonable scope with respect to the cyclopropane component affording the corresponding alkylated ferrocene derivatives in useful yields. An alternative approach to these functionalized ferrocene derivatives involving arylation of a ferrocene-decorated donor--acceptor cyclopropane derivative is also disclosed. Both processes rely on a facile regioselective ring-opening of the donor--acceptor cyclopropane. [ABSTRACT FROM AUTHOR]

The InCl3-catalyzed reaction of ferrocene with orthohydroxybenzyl alcohols is reported and represents a convenient route for the synthesis of ferrocenyl phenols. This carbon–carbon bond forming process is believed to proceed through an ortho-quinone methide intermediate that can be interceptedby ferrocene through a Friedel–Crafts-type process. Preliminary cytotoxic screening carried out on several cancer cell lines revealed that some of the compounds exhibit moderate cytotoxicity [ABSTRACT FROM AUTHOR]

An efficient activator-free protocol for the coupling of o-hydroxybenzyl alcohols and azoles in water has been developed. This C-N bond-formation process is supposed to proceed through an ortho-quinone methide intermediate. A broad range of o-hydroxybenzyl alcohols that include those with alkenyl and alkynyl functionalities is compatible with this protocol. In most cases, the products are isolated in good to excellent yields without chromatographic purification. Preliminary results demonstrated that this methodology can also be used for the generation and trapping of isomeric para-quinone methide intermediates. [ABSTRACT FROM AUTHOR]

Transition metal-catalyzed transformations of vinyldiazo compounds have become a versatile tool in organic synthesis. Although several transition metals have been investigated for this purpose, this field has been mainly dominated by dirhodium catalysts. Remarkable levels of chemo-, regio-, diastereo- and enantioselectivity have been reached in some of these rhodium-catalyzed transformations. In the last few years coinage metals have also emerged as useful catalysts in transformations involving vinyldiazo compounds. In some cases, highly efficient catalyst-dependent protocols arising from divergent mechanistic pathways have been reported. In this Personal Account, we aim to showcase recent advances in metal coinage catalyzed transformations of vinyldiazoacetates, an exciting field of research to which our group has actively contributed in the last few years. [ABSTRACT FROM AUTHOR]

An efficient, metal-free, silicon-hydrogen bond functionalization based on the microwave-assisted reaction of readily available enynones and silanes is reported. This process seemingly proceeds through a 2-furyl carbene species, a particularly elusive intermediate. Preliminary studies on the metal-free oxygen-hydrogen and nitrogen-hydrogen bond functionalization of representative alcohols, azoles and sulfonamides are also provided. [ABSTRACT FROM AUTHOR]

Ferrocene, Nitrogen heterocycles, Fused ring systems, Planar chirality, Asymmetric catalysis Keywords: Ferrocene; Nitrogen heterocycles; Fused ring systems; Planar chirality; Asymmetric catalysis EN Ferrocene Nitrogen heterocycles Fused ring systems Planar chirality Asymmetric catalysis 1 1 1 03/24/22 20220318 NES 220318 B The Front Cover b shows the fusion of ferrocene and heterocyclic compounds (exemplified by pyridine). The chemistry of ferrocene-fused nitrogen heterocycles has recently become an exciting field of research. [Extracted from the article]