Gold(l)-catalyzed formation of furans by a Claisen type rearrangement of ynenyl allyl ethers

International audienceA series of ynenyl allyl ethers were rearranged into polysubstituted furans in the presence of a gold(I) catalyst. It is proposed that the transformation involves a Claisen-type rearrangement that allows the efficient creation of quaternary centers under mild experimental conditions. © 2011 Istrate and Gagosz

Recent progress towards transition metal-catalyzed synthesis of γ-lactams

The occurrence of the γ-lactam unit in the framework of various biologically active compounds has greatly contributed to the design and development of new synthetic transformations to access this important structural motif. Among the numerous methods developed so far, those based on transition metal catalysis are of high value as they generally allow efficient and selective access to functionalized γ-lactams under rather mild reaction conditions. An overview of the recent advances in this field is presented herein. Metal-catalyzed processes are reviewed by highlighting their specificity and applicability, and the mechanistic rationale is presented where possible. ? 2014 The Royal Society of Chemistry

Recent developments in gold catalysis

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Unusual Gold(I)-Catalyzed Isomerization of 3-Hydroxylated 1,5-Enynes: Highly Substrate-Dependant Reaction Manifolds

The gold(I) isomerisation of diversely substituted 3-hydroxylated enynes has led to the discovery of three new unreported skeletal rearrangements furnishing structures such as alkylidene-cyclopentenes, cyclohexadienes or Α,Β-unsaturated aldehydes under very mild conditions

Unusual gold(I)-catalyzed isomerization of 3-hydroxylated 1,5-enynes: Highly substrate-dependent reaction manifolds

International audience(Chemical Equation Presented) The gold(I) isomerization of diversely substituted 3-hydroxylated enynes has led to the discovery of three new unreported skeletal rearrangements furnishing structures such as alkylidene-cyclopentenes, cyclohexadienes or a,ß-unsaturated aldehydes under very mild conditions. © 2005 American Chemical Society

The radical chemistry of xanthates: A powerful tool

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La catalyse à l'or: Un outil synthétique en devenir [Gold catalysis: A promising synthetic tool]

International audienceLa catalyse à l'or est devenue en quelques années un domaine de recherche particulièrement actif. La raison d'un tel engouement est à mettre au compte de la réactivité singulière des espèces d'or électrophiles, de leur forte acidité de Lewis et de la possibilité de réaliser, de manière sélective et efficace, des transformations difficilement accessibles par d'autres moyens. Cet article traite des différents aspects liés à la réactivité des complexes d'or en catalyse, en mettant l'accent sur le travail réalisé dans notre groupe de recherche. Les possibilités synthétiques, liées à la formation de liaisons carbone-hétéroatome ou carbone-carbone, après activation d'une insaturation (alcyne, allène ou alcène) par une espèce d'or électrophile, sont illustrées par des exemples issus de nos études. [Gold catalysis has become a particularly active area of research within only a few years. The reasons for such a recent interest are intimately linked with the singular reactivity of electrophilic gold species, their high Lewis acidity, and the possibility to selectively and efficiently perform a plethora of transformations that would not be as easily achieved by other means. This article is a brief overview of the research we have carried out in this field, summarizing various aspects of the reactivity of gold complexes in catalysis. The synthetic opportunities for the creation of carbon-carbon or carbon-heteroatom bonds, following the activation of an unsaturation (alkyne, allene, alkene) by an electrophilic gold species, are illustrated by a series of examples from our studies.

Synthesis and Reactivity of Air-Stable N-Heterocyclic Carbene Gold(I) Bis(trifluoromethanesulfonyl)imidate Complexes

International audienceA study concerning the synthesis of new N-heterocyclic carbene gold(I) complexes using the bis(trifluoromethanesulfonyl)imidate moiety (Tf2N-) as a weakly coordinating counteranion is described. These new air-stable (NCH)AuNTf2 complexes are convenient to prepare, stoe, and handle and proved to be active in a range of gold(I)-catalyzed transformations

Expedited Total Synthesis of Brevianamide A via the Strategic Use of Gold(I)-Catalysis

Two concise and complementary routes to the polycyclic alkaloid brevianamide A from readily available amino acid building blocks is presented. Key to the synthesis is the strategic use of a gold(I)-catalyzed cascade process that quickly assembles the characteristic pseudoindoxyl motif of the natural product along with the two adjacent quaternary centers in a single step. This sequence, which exemplifies the structural complexity that can be achieved with gold catalysis, allowed for the shortest and highest yielding synthesis of brevianamide A to date (4 steps LLS, 14% overall yield

Synthesis of functionalized furans via gold(I)-catalyzed Claisen-type rearrangement

International audience(Chemical Equation Presented) Gold(I)-catalyzed cyclization of pentenynyl allyl ethers allows the rapid construction of functionalized furans. The concerted oxy-Claisen-type mechanism induces a complete selectivity of the process and allows the easy formation of quaternary centers. © 2008 American Chemical Society