Gold-Catalyzed Cascade Reaction Research Articles

Stereoselective Double Spirocyclization of 2-Benzyl-3-alkynyl Chromone with Nitrone via Gold-Catalyzed Cascade Reactions.

A novel, highly stereoselective gold-catalyzed spirocyclization of 2-benzyl-3-alkynyl chromone with nitrone is described. This cascade reaction involves gold-catalyzed cycloisomerization, nitrone-olefin [3 + 2]-annulation, alkene oxidation, and rearrangement for the formation of spirocyclic products. Interestingly, the isoxazolidine ring generated from [3 + 2]-annulation donates oxygen to alkene to generate a new pyran-3(4H)-one and azetidine ring for dispiro-benzofuran formation upon heating. This work demonstrates the one-pot, gold-catalyzed, multiple-step reaction, and the reaction temperature directly affects the formation of spirocyclic products.

Gold-Catalyzed Cascade Reaction of Yne-Enones with Iminooxindoles, Access to 3,2'-Pyrrolidinyl-Spirooxindole Derivatives.

Herein, a gold-catalyzed cascade reaction of yne-enones with iminooxindoles has been developed through a cascade cycloisomerization/(3 + 2) annulation process. This approach provides a straightforward and efficient route for the synthesis of functionalized 3,2'-pyrrolidinyl-spirooxindoles in high reactivity and broad substrate scope with excellent cis-selectivity. Moreover, the subsequent functionalization of furan units allows for the diverse synthesis of spirooxindole derivatives, which have demonstrated good antitumoral activity.

Gold-Catalyzed Cascade Reaction of Diynamides with Allylic Alcohols: A Versatile Platform to Allenamide, 2-Aminofuran and Bridged [2.2.2]Octadiene Derivatives.

Transition metal-catalyzed divergent synthesis through alternation of the catalyst is appealing, as it provides an operationally simple way to access different valuable products, while using the same reactants as starting materials. Herein, a gold-catalyzed cascade reaction of conjugated diynamides with allylic alcohols is described. By variation of the catalysts, substituted allenes and furans could be obtained selectively. Mechanistic studies indicate that, after the addition of allylic alcohol to gold-activated diynamide, a [3,3]-sigmatropic rearrangement would take place and lead to the formation of a common reactive intermediate, which would further convert to the final products selectively. Further variation of the structure of diynamides has unveiled an additional reaction sequence involving intramolecular Himbert arene/allene Diels-Alder cycloaddition to afford a series of dearomatized products bearing bicyclo[2,2,2]octadiene core.

Advancements in Gold-Catalyzed Cascade Reactions to Access Carbocycles and Heterocycles: An Overview.

This review summarizes recent developments (from 2006 to 2022) in numerous important and efficient carbo- and heterocycle generations using gold-catalyzed cascade protocols. Herein, methodologies involve selectivity, cost-effectiveness, and ease of product formation being controlled by the ligand as well as the counter anion, catalyst, substrate, and reaction conditions. Gold-catalyzed cascade reactions covered different strategies through the compilation of various approaches such as cyclization, hydroarylation, intermolecular and intramolecular cascade reactions, etc. This entitled reaction is also useful for the synthesis of spiro, fused, bridged carbo- and heterocycles.

Gold catalyzed cascade reaction of 2-Alkynyl arylazides with 1,2,3-Triazoles to provide N1- and N2-Indol-3-yl 1,2,3-Triazole derivatives

A new method was developed to prepare N1 and N2-indol-3-yl 1,2,3-trizole products through gold catalyzed cascade reaction of o-alkynyl arylazides with 1,2,3-triazoles, in which, the in-situ generated α-imino gold carbene intermediate was intercepted by various types of triazole compounds. N1-selective nucleophilic attack was favored to give moderate to high N1/N2 selectivity. In addition, indol-3-yl pyrazole compounds were also prepared by using the similar method.

Gold(I)-Catalyzed Cascade Cyclization of Anilines with Diynes: Controllable Formation of Eight-Membered Ring-Fused Indoles and Propellane-Type Indolines

Heterocycle-fused indoles or indolines are distributed widely in a variety of natural products, bioactive agents, and pharmaceuticals. Herein, we describe the development of gold-catalyzed cascade reactions of anilines with diynes to form eight-membered ring-fused indoles and propellane-type indolines, both of which proceed through an intramolecular 5-endo-dig hydroamination followed by an 8-endo-dig cycloisomerization. Controllable formation of eight-membered ring-fused indoles and propellane-type indolines was achieved through selection of the ligands and/or solvents. Protic solvents such as alcohols or IPr ligand favored the formation of eight-membered ring-fused indoles, whereas the use of Buchwald's type ligands and/or nonpolar solvents gave propellane-type indoline predominantly. This reaction provides rapid access to two types of fused nitrogen heterocycles from simple aniline derivatives.

Gold(iii)-catalyzed azide-yne cyclization/O-H insertion cascade reaction for the expeditious construction of 3-alkoxy-4-quinolinone frameworks.

A gold-catalyzed 6-endo-dig azide-yne cyclization/O-H insertion cascade reaction of azide-tethered alkynes with alcohols has been developed, and it provides an expeditious access to 3-alkoxy-4-quinoline derivatives in good to high yields under mild and neutral reaction conditions with broad substrate generality. The utility of this method is emphasized by a scalable experiment and concise total synthesis of a bioactive natural product Leiokinine A, and other bioactive quinoline analogs.

Green and Facile Assembly of Diverse Fused N-Heterocycles Using Gold-Catalyzed Cascade Reactions in Water.

The present study describes an AuPPh3Cl/AgSbF6-catalyzed cascade reaction between amine nucleophiles and alkynoic acids in water. This process proceeds in high step economy with water as the sole coproduct, and leads to the generation of two rings, together with the formation of three new bonds in a single operation. This green cascade process exhibits valuable features such as low catalyst loading, good to excellent yields, high efficiency in bond formation, excellent selectivity, great tolerance of functional groups, and extraordinarily broad substrate scope. In addition, this is the first example of the generation of an indole/thiophene/pyrrole/pyridine/naphthalene/benzene-fused N-heterocycle library through gold catalysis in water from readily available materials. Notably, the discovery of antibacterial molecules from this library demonstrates its high quality and potential for the identification of active pharmaceutical ingredients.

Gold-Catalyzed Atom-Economic Synthesis of Sulfone-Containing Pyrrolo[2,1-a]isoquinolines from Diynamides: Evidence for Consecutive Sulfonyl Migration

A gold-catalyzed cascade reaction of conjugated diynamides has been developed. In this way, a series of sulfone-containing pyrrolo[2,1-a]isoquinolines featuring the core structural motifs of lamellarin alkaloids were prepared atom economically. Mechanistic studies including DFT calculations uncovered a consecutive 1,2-migration of the sulfonyl group for the formation of a pyrrole ring.

Diastereoselective Synthesis of Polysubstituted Spirocyclopenta[ c]furans by Gold-Catalyzed Cascade Reaction.

With the synergistic activation of alkynyl alcohols and alkynyl enones by a single gold catalyst, diverse multisubstituted spirocyclopenta[ c]furans were synthesized in good to excellent yields under mild conditions. Three rings were constructed efficiently in one pot from easily available acyclic starting materials.

Gold-Catalyzed Cascade Reaction of β-(2-Aminophenyl)-α,β-ynones with Ynamides: A Sequential Route to Polysubstituted 2-Aminoquinolines.

A novel, efficient, and mild synthetic route for the preparation of 2-aminoquinolines via a gold-catalyzed cascade reaction of β-(2-aminophenyl)-α,β-ynones with ynamides has been developed. This process tolerates a wide range of functionalities such as halogen, alkyl, aryl, and heteroaryl groups, leading to original heterocycles in fair to very good yields.

Computational Study on Gold-Catalyzed Cascade Reactions of 1,4-Diynes and Pyrroles: Mechanism, Regioselectivity, Role of Catalyst, and Effects of Substituent and Solvent

This study is devoted to a theoretical investigation of the mechanism, regioselectivity, role of catalyst, and effect of substituent and solvent in the Au-catalyzed cascade reaction between 1,4-diynes and pyrroles. Density functional theory (DFT) calculations indicate that this reaction comprises four principal stages: (1) formation of different intermediates through the first intermolecular hydroarylation, (2) 1,3-H transfer to give the enyne intermediates, (3) a second intermolecular hydroarylation, and (4) a second proton transfer along with Au(I) catalyst regeneration and final product formation. In addition, the computational results suggest that the first regioselectivity is determined by the electronic effects of the reagents. However, the torsional strains within the transition structures (intramolecular cyclization) and electronic effects of enyne intermediates would account for the second regioselectivity. A global reactivity index (GRI) analysis for different gold catalysts (namely, IPrAu+, PPh...

Diversity-Oriented Synthesis of Natural Products via Gold-Catalyzed Cascade Reactions

This account describes our group’s latest research in the field of diversity-oriented synthesis of natural products via gold-catalyzed cascade reactions. We present two general strategies based on gold-catalyzed cycloisomerization: a gold-catalyzed cascade reaction of 1,7-diynes and a pinacol-terminated gold-catalyzed cascade reaction. We highlight our development of synthetic methods for the construction of biologically active natural products by using these two strategies.1 Introduction2 Gold-Catalyzed Cascade Reactions of 1,7-Diynes2.1 Collective Synthesis of C15 Oxygenated Drimane-Type Sesquiterpenoids2.2 Synthesis of Left-Wing Fragment of Azadirachtin I2.3 Collective Synthesis of Cladiellins3 Pinacol-Terminated Gold-Catalyzed Cascade Reaction3.1 Asymmetric Formal Total Synthesis of (+)-Cortistatins3.2 Total Synthesis of Orientalol F3.3 Asymmetric Total Synthesis of (–)-Farnesiferol C4 Summary and Outlook

Synthesis of benzannulated spiroketals with gold-catalyzed cycloisomerization/spiroketalization cascade

An unprecedented gold-catalyzed cascade reaction of alkynyl alcohol and quinone monoimines to diverse 5,5-benzannulated spiroketals has been successfully developed.

Recent Advances in the Synthesis of Heterocycles via Gold-catalyzed Cascade Reactions: A Review

Recent Advances in the Synthesis of Heterocycles via Gold-catalyzed Cascade Reactions: A Review

Gold-Catalyzed Cascade Reaction of Skipped Diynes for the Construction of a Cyclohepta[b]pyrrole Scaffold.

A gold-catalyzed cascade reaction of skipped diynes (1,4-diynes) and pyrroles has been developed. This reaction proceeds by the consecutive regioselective hydroarylation of two alkynes with a pyrrole, followed by a 7-endo-dig cyclization to give 1,6-dihydrocyclohepta[b]pyrroles in good yields. The direct synthesis of cyclohepta[b]indoles using indole nucleophiles has also been reported.

ChemInform Abstract: Self‐Relay Gold(I)‐Catalyzed Pictet—Spengler/Cyclization Cascade Reaction for the Rapid Elaboration of Pentacyclic Indole Derivatives.

ChemInformVolume 47, Issue 17 Heterocyclic Compounds ChemInform Abstract: Self-Relay Gold(I)-Catalyzed Pictet—Spengler/Cyclization Cascade Reaction for the Rapid Elaboration of Pentacyclic Indole Derivatives. Valerian Gobe, Valerian Gobe Inst. Chim. Subst. Nat., CNRS, Univ. Paris-Sud, F-91198 Gif-sur-Yvette, Fr.Search for more papers by this authorPascal Retailleau, Pascal Retailleau Inst. Chim. Subst. Nat., CNRS, Univ. Paris-Sud, F-91198 Gif-sur-Yvette, Fr.Search for more papers by this authorXavier Guinchard, Xavier Guinchard Inst. Chim. Subst. Nat., CNRS, Univ. Paris-Sud, F-91198 Gif-sur-Yvette, Fr.Search for more papers by this author Valerian Gobe, Valerian Gobe Inst. Chim. Subst. Nat., CNRS, Univ. Paris-Sud, F-91198 Gif-sur-Yvette, Fr.Search for more papers by this authorPascal Retailleau, Pascal Retailleau Inst. Chim. Subst. Nat., CNRS, Univ. Paris-Sud, F-91198 Gif-sur-Yvette, Fr.Search for more papers by this authorXavier Guinchard, Xavier Guinchard Inst. Chim. Subst. Nat., CNRS, Univ. Paris-Sud, F-91198 Gif-sur-Yvette, Fr.Search for more papers by this author First published: 08 April 2016 https://doi.org/10.1002/chin.201617169Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume47, Issue17April, 2016 RelatedInformation

Gold-Catalyzed Enantio- and Diastereoselective Syntheses of Left Fragments of Azadirachtin/Meliacarpin-Type Limonoids.

Meliacarpin-type limonoids are an important class of organic insecticides. Their syntheses are challenging due to their chemical complexity. Here, we report the highly enantio- and diastereoselective synthesis of the left fragments of azadirachtin I and 1-cinnamoylmelianolone, being two important family members of meliacarpin-type limonoids, via pairwise palladium- and gold-catalyzed cascade reactions. Gold-catalyzed reactions of 1,7-diynes were performed as model studies, and the efficient construction of tetracyclic late-stage intermediates was achieved on the basis of this key transformation. Our unique route gave both of the left fragments in 23 steps from the commercially available chiral starting material (-)-carvone. This study significantly advances research on the synthesis of the meliacarpin-type limonoids.

Convergent Synthesis of 2-Aryl-Substituted Quinolines by Gold-Catalyzed Cascade Reaction.

Gold-catalyzed auto-tandem catalysis has been developed for synthesizing 2-aryl-substituted quinolines. The reaction of an aniline bearing an acetal moiety with an aryl alkyne proceeded via formal [4+2]-cycloaddition, which involved the addition of gold acetylide to an oxonium ion to give amino alkyne intermediate and sequential 6-endo-dig cyclization of amino alkyne intermediate by attacking of nitrogen to alkyne moiety activated by gold catalyst. The cationic gold catalyst promoted two different processes by enhancing the nucleophilicity and electrophilicity of alkyne. This convergent synthetic methodology enabled the synthesis of a variety of 2-aryl-substituted quinolines.

Self-Relay Gold(I)-Catalyzed Pictet-Spengler/Cyclization Cascade Reaction for the Rapid Elaboration of Pentacyclic Indole Derivatives.

Gold-catalyzed cascade reactions allow the rapid elaboration of pentacyclic indolo[2,3-a]quinolizidines from N-allyl tryptamines and ortho-alkynylarylaldehydes. The tandem process combines a gold-catalyzed Pictet-Spengler reaction and a cyclization occurring concomitantly with an allyl transfer from the nitrogen atom to the stilbene function. Various substituted allyls were successfully transferred, furnishing the products in yields typically ranging from 60-98 % in high diastereoselectivity. Tryptamines bearing a butenol chain undergo an additional cyclization to chiral hemiaminals in high diastereoselectivities.