Gold(I)-Catalyzed Formal Intramolecular Dehydro-Diels–Alder Reaction of Ynamide-ynes: Synthesis of Functionalized Benzo[<i>b</i>]carbazoles

Xu, Wei; Wang, Gaonan; Xie, Xin; Liu, Yuanhong

doi:10.1021/acs.orglett.8b01145

Cited by 55 publications

(24 citation statements)

References 42 publications

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“…For example, several recent reports have harnessed dual gold-catalysts in cycloaromatisations via TDDA reactions of enediynes. [3][4][5][6][7] In these cases the enediyne is not fully conjugated but has the alkyne and enyne units linked via a heteroatom tether leading to a diverse range of fused heterocyclic benzenoid structures of biological signicance (Scheme 1b).…”

Section: Introductionmentioning

confidence: 99%

Rhodium-catalysed tetradehydro-Diels–Alder reactions of enediynes via a rhodium-stabilized cyclic allene

et al. 2020

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Section: Introductionmentioning

confidence: 99%

Rhodium-catalysed tetradehydro-Diels–Alder reactions of enediynes via a rhodium-stabilized cyclic allene

et al. 2020

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“…mol% of JohnPhos/Au(MeCN)SbF 6 at room temperature (Scheme 153). 100 The very rare possibility of the preparation of 5-phenyl-10-tosyl-10H-pyrido[2,3-b]carbazole (530) from the corresponding pyridine-containing substrate by this approach should also be mentioned in this context. 100 It should be noted, that cyclization of the 'inversed' starting ynamide-tethered alkynes 536-539 can be carried out without the participation of any catalyst; however, this process requires sufficiently high temperatures and gives the corresponding benzo [b] 101 In comparison with the data from previous work, 100 the nitrogen-tethered triple bonds in diynes 536-539 probably exhibit weaker dienophilic properties than the aryl-tethered triple bonds in substrates 525 (see Scheme 153).…”

Section: Review Synthesismentioning

confidence: 99%

IntraMolecular Diels–Alder Reactions of Vinylarenes and Alkynyl Arenes (the IMDAV Reaction)

Krishna¹,

Grudinin²,

Nikitina³

et al. 2021

Synthesis

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This comprehensive review summarizes the published literature data concerning the intramolecular Diels–Alder reactions of vinylarenes (the IMDAV reaction) and alkynyl arenes from 1970 to 2019, and covers mainly intramolecular [4+2] cycloaddition reactions of vinyl- or acetylene-substituted furans, thiophenes, pyrroles, indoles, imidazoles, benzenes, and naphthalenes, in which the unsaturated substituent is linked directly to an arene moiety. The selected area of the Diels–Alder reaction differs from other forms of [4+2] cycloadditions due to the uniqueness of the diene fragment, which, along with an exocyclic multiple bond, includes the double bond of an aromatic or heteroaromatic nucleus in its system. Thus, during the formation of the [4+2] cycloaddition intermediate, the aromaticity of furan, thiophene and even benzene rings is broken, leading, as a rule, to the formation of heterocyclic structures rarely accessible by other methods, in contrast to the majority of intermolecular Diels–Alder reactions, with the highest degree of chemo-, regio-, and diastereoselectivity. Therefore, the IMDAV approach is often used for the synthesis of naturally occurring and bioactive molecules, which are also discussed in this review alongside other applications of this reaction. Whenever possible, we have tried to avoid examples of radical, photochemical, oxidative, precious-metal-complex-catalyzed cyclizations and other types of formal [4+2] cycloadditions, focusing on thermal Diels–Alder reactions in the first step, according to the classical mechanism. The second stage of the process, aromatization, is unique for many initial substrates, and hence considerable attention in this overview is given to the detailed description of the reaction mechanisms.1 Introduction2 IMDAV Reactions of Vinylfurans2.1 Alkenes as Internal Dienophiles2.2 Alkynes and Allenes as Internal Dienophiles3 IMDAV Reactions of Vinylthiophenes3.1 Alkenes as Internal Dienophiles3.2 Alkynes as Internal Dienophiles4 IMDAV Reactions of Vinylbenzothiophenes5 IMDAV Reactions of Vinylpyrroles6 IMDAV Reactions of Vinylindoles6.1 Alkenes as Internal Dienophiles6.2 Alkynes as Internal Dienophiles7 IMDAV Reactions of Styrenes and Vinylnaphthalenes7.1 Alkenes as Internal Dienophiles7.2 Alkynes as Internal Dienophiles7.3 Alkynes as Internal Dienophiles in Aryl Acetylenes (the Intramolecular Dehydro Diels–Alder Reaction)8 IMDAV Reactions of Vinylimidazoles, Vinylisoxazoles and Vinylpyridines9 Conclusion10 Abbreviations

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“…In 2018, Liu et al designed a new route toward benzo[ b ]carbazoles 49 involving the [JohnPhosAuNCMe] + -catalyzed cycloisomerization of the ynamide-ynes 46 via a formal dehydro-Diels-Alder reaction at room temperature (Figure 5B). Initial gold-activated keteniminium ions 47 undergo a cyclization affording the vinyl cations 48 which evolve toward the final tetracycles 49 by a benzoannulation reaction (Xu et al, 2018). The same catalyst, [JohnPhosAuNCMe]SbF 6 , mediates the transformation of ynamides 50 into tetrahydro[ g ]quinolines 52 (Figure 5C).…”

Section: Gold-catalyzed Isomerization Processes Involving An Initimentioning

confidence: 99%

Gold-Catalyzed Homogeneous (Cyclo)Isomerization Reactions

2019

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Gold is currently one of the most used metals in organometallic catalysis. The ability of gold to activate unsaturated groups in different modes, together with its tolerance to a wide range of functional groups and reaction conditions, turns gold-based complexes into efficient and highly sought after catalysts. Natural products and relevant compounds with biological and pharmaceutical activity are often characterized by complex molecular structures. (Cyclo)isomerization reactions are often a useful strategy for the generation of this molecular complexity from synthetically accessible reactants. In this review, we collect the most recent contributions in which gold(I)- and/or gold(III)-catalysts mediate intramolecular (cyclo)isomerization transformations of unsaturated species, which commonly feature allene or alkyne motifs, and organize them depending on the substrate and the reaction type.

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Gold(I)-Catalyzed Formal Intramolecular Dehydro-Diels–Alder Reaction of Ynamide-ynes: Synthesis of Functionalized Benzo[b]carbazoles

Cited by 55 publications

References 42 publications

Rhodium-catalysed tetradehydro-Diels–Alder reactions of enediynes via a rhodium-stabilized cyclic allene

Rhodium-catalysed tetradehydro-Diels–Alder reactions of enediynes via a rhodium-stabilized cyclic allene

IntraMolecular Diels–Alder Reactions of Vinylarenes and Alkynyl Arenes (the IMDAV Reaction)

Gold-Catalyzed Homogeneous (Cyclo)Isomerization Reactions

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