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.

We report the gold-catalyzed reaction of vinyldiazo compounds and alkenylsilanes to produce skipped dienes, which are common structural motifs in an array of bioactive compounds. This carbon–carbon bond-forming transformation proceeds with complete regio- and stereoselectivity with the silyl group serving as a regio- and stereocontrolling element. Likewise, the use of alkynylsilanes as reaction partners yielded skipped enynes resulting from a C(sp)–C(sp 3 ) coupling. Mechanistic experiments and DFT studies have provided support for a stepwise mechanism.

We report the regioselective synthesis of silyl-substituted cyclopentadienyl esters through gold-catalyzed migratory cycloisomerization of silyl-substituted vinylallenes. This transformation is proposed to proceed through a perfectly orchestrated sequence of events including Nazarov-like cyclization and several silyl and hydrogen rearrangements. Furthermore, exploiting the multifaceted nature of the gold catalyst, we have also identified suitable conditions for the synthesis of these cyclopentadienes in a more straightforward manner through gold-catalyzed reaction of propargyl esters and alkynylsilanes.

The Front Cover 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. From a synthetic point of view, the transfer to ferrocene of some of the powerful transition‐metal‐catalyzed methodologies developed for the C−H bond functionalization of benzene derivatives has no doubt contributed to this extraordinary development. Moreover, because of the planar chirality most of these ferrocene‐fused systems exhibit, some of them have found interesting applications as organocatalysts in asymmetric catalysis. In this review, we showcase recent advances in the synthesis and applications of this type of fused systems. The cover was designed by Illan López. More information can be found in the Review by L. A. López and co‐workers.

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 metal-lacyclic 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.

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.

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 scaleup 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.Scheme 1. Intermolecular trapping of gold carbene intermediates arising from propargyl esters with alkynes.

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