Nitrones as Trapping Reagents of α,β‐Unsaturated Carbene Intermediates – [1,2]Oxazino[5,4‐<i>b</i>]indoles by a Platinum‐ Catalyzed Intermolecular [3+3] Cycloaddition

Yang, Weibo; Wang, Tao; Yu, Yang; Shi, Shuai; Zhang, Tuo; Hashmi, A. Stephen K.

doi:10.1002/adsc.201300338

Cited by 36 publications

(13 citation statements)

References 43 publications

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“…[1] Recently, the metal-catalyzed cycloaddition of nitrones with various unsaturated hydrocarbons has proven to be an efficient tool to produce nitrogen-containing heterocycles. Although the reactivity of nitrones toward different synthons has been extensively studied, most attention has been given to [3+2], [2] [3+3], [3][4][5][6][7] [4+3], [8, 9] and [2+2+3] [10] cycloadditions (Scheme 1 a). In these intriguing studies, nitrones exclusively serve as 1,3-dipolar reagents to afford five-, six-, and sevenmembered heterocycles.…”

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confidence: 99%

Rhodium‐Catalyzed Cyclization of Diynes with Nitrones: A Formal [2+2+5] Approach to Bridged Eight‐Membered Heterocycles

Wang

Hao

et al. 2014

Angew Chem Int Ed

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N-aryl-substituted nitrones were employed as five-atom coupling partners in the rhodium-catalyzed cyclization with diynes. In this reaction, the nitrone moiety served as a directing group for the catalytic C-H activation of the N-aryl ring. This formal [2+2+5] approach allows rapid access to bridged eight-membered heterocycles with broad substrate scope. The results of this study may provide new insight into the chemistry of nitrones and find applications in the synthesis of other heterocycles.

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confidence: 99%

Rhodium‐Catalyzed Cyclization of Diynes with Nitrones: A Formal [2+2+5] Approach to Bridged Eight‐Membered Heterocycles

Wang

Hao

et al. 2014

Angew Chem Int Ed

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“…As an alternative to vinyldiazoacetate reagents, several research groups have used metal-catalyzed cycloisomerization reactions to generate transition-metal complexes that undergo stepwise [3+ +3]-or [3+ +4]-cycloaddition reactions with nitrones to form dihydrooxazines or tetrahydrooxazepines. [15][16][17][18][19][20][21] Zhang and co-workersh ave investigated the use of gold(I)-catalyzed cycloisomerizationsof2-alkynyl-2-alkenyl-1-ones 2.20 to generate furanyl gold-complexes such as 2.21 that undergo stepwise cycloadditions with nitrones to form fused-bicyclic dihydrooxazines 2.23 with high diastereoselectivity (Scheme 8). [15][16][17] In an initial communication, the Zhang group showed that [3+ +2]-dipolar cycloadditions between an itrone and the alkene or alkyne functionality of 2.20 did not compete with the synthesis of 2.23 in the presence of Ph 3 PAuOTf and that the dihydrooxazine synthesis was tolerant of av arietyo f alkyl, aryl, and heteroaryl substituents on both the ene-yneone and the nitrone reagents.…”

Section: Tandemcycloisomerization and Cycloaddition Reactions Of Nitrmentioning

confidence: 99%

“…While Zhang and co-workers focused on the cyclization of yne-onesf or the generation of alkenylg old intermediates to be paired with nitrones for stepwise [3+ +3]-and [4+ +3]-cycloaddition reactions, the groups of Liu and Hashmi investigated the tandem cyclizationsa nd cycloadditions of ene-ynes 2.38 and alkynyl anilines 2.44,r espectively. [20,21] As illustrated in Scheme 10 A, Liu and co-workers showed that ene-ynesu ndergo cyclizationst of orm cyclopropylg old-carbenoid species 2.40,w hich can undergo stepwise [4+ +3]-cycloadditions with Scheme9.Gold-catalyzed cyclopropyl-and epoxy-yne-one cyclizationsfor the generation of spirocyclic furanyl goldcomplexes and their [4+ +3]-cycloaddition reactionsw ith nitronesf rom Zhang and co-workers.…”

Section: Tandemcycloisomerization and Cycloaddition Reactions Of Nitrmentioning

confidence: 99%

“…Recently,H ashmi and co-workersh ave also discovered that treatment of alkyne-tethered aniline 2.44 with ap latinum catalyst promotes ac yclization to form carbenoid intermediate 2.45,w hich can be trapped with nitrones 2.18 to form indole-fused dihydro-1,2-oxazines 2.47 (Scheme 10 B). [21] This transformation favors aryl nitrones with electron-withdrawings ubstituents and tolerates av ariety of substitution patternso nt he aniline.…”

Section: Tandemcycloisomerization and Cycloaddition Reactions Of Nitrmentioning

confidence: 99%

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Diverse Applications of Nitrones for the Synthesis of Heterocyclic Compounds

Anderson

2015

Asian J Org Chem

128

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Although best known for their [3+ +2]-dipolar cycloaddition reactivity and use in the preparationo fi soxazolines and isoxazolidines,n itrones are versatile reagents that undergo av ariety of transformationsf or the synthesis of ad iverse array of heterocyclic compounds. Theb readth of heterocycle synthesis using nitrone reagentsi ncludes: 1) stepwise [3+ +3]-cycloaddition reactions of nitrones with vinyl diazoacetates, transition-metal-coordinated cycloisomerization intermediates, trimethylenem ethanes, and cyclopropane diesters to form dihydro-a nd tetrahydro-1,2-oxazines;2 )internal redox cyclization reactions of alkyne-tetheredn itrones to provide access to azabicyclooctanes,i soindoles, aminoindanones, and isoquinolones;3 )electrocyclizationso fi ns itu generated N-allenylnitrones to form pyridines and azetidine-N-oxides, as well as metal-catalyzed cyclizationsa nd rearrangements of nitrones to form azepine-N-oxides, spirocyclic isoxazolines, and a,b-epoxyimines;a nd 4) the use of [3+ +2]cycloaddition reactions of nitrones to trigger cascade reactions for the formationo ft etrahydrooxazepines, dihydrocarbazoles, and benzoindolizines. This Focus Review aims to highlight these diverse applicationso fn itrones for the synthesis of heterocyclest oe mphasize the broad utility of these reactive intermediates andt oi nspire their furtherd evelopment as important synthons beyond the scope of traditional [3+ +2]-dipolar cycloaddition reactions. Scheme1.[3+ +2]-Dipolar cycloadditions of nitrones and their application to the synthesis of naturalproducts and biologically active compounds:Diverse applicationsofn itrones for the synthesis of heterocyclic compounds.[a] Prof. Dr.L.L.A nderson 2. Formal [3+ +3]-Cycloadditions of Nitrones and [4+ +2]-Cycloadditions of N-Alkenylnitrones.Formal [3+ +3]-cycloadditions of nitrones have been investigated as alternative methods for the synthesis of dihydro-and tetrahydro-1,2-oxazines and offer new routes to these heterocycles that are unique from traditional [4+ +2]-cycloadditions of dienes and nitrosobenzenes. [8] The nitrone cycloaddition partners discussed below include vinyldiazoacetates, alkenyl gold complexes,m etal carbenoids generated through cycloisomerization processes, trimethylene methanes, and cyclopropane diesters (Scheme 3A). The synthesiso fN-alkenylnitrones has also prompted an investigation of these electron-deficient azadienesa si nverse-demand cycloaddition partners for the synthesis of six-membered-ring nitrones that are poised to undergo furtherf unctionalization (Scheme 3B). Prof. Laura L. Anderson receivedh er B.A. from Knox College in 2000 and moved to the University of California, Berkeley,f or her graduate studies where she worked with Prof. John Arnold and Prof. Robert G. Bergman developing new hydroamination catalystsa nd studying the reactivity of transition metal imido complexes. After obtaining her Ph.D. in 2005, Prof. Anderson movedt ot he Universityo f California, Irvine, wheres he completed aR uth L. Kirschstein NIH postdoctoral fellowship with Pr...

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“…Scientific interest in this family of alkaloids stems from a number of factors, including their bioactivity and biomedical applications [4][5][6]. Therefore, the synthesis and functionalization of the indole nucleus has been a topic of increasing interest [7][8][9][10][11][12][13][14][15][16]. In some of the recent literature, the synthesis of indole derivatives was reported via direct 2,3-disubstitutions [17,18], C-H activations of the heterocyclic system [19,20] and Pd-catalysed couplings [21][22][23][24], while other studies have used oxidations [25] or cyclization [26,27] reactions.…”

Section: Introductionmentioning

confidence: 99%

A novel Pd-catalysed sequential carbonylation/cyclization approach toward bis- N -heterocycles: rationalization by electronic structure calculations

et al. 2018

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An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as N-nucleophiles, gives access, in one pot, to a new family of indole-based N-heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation (PCO = 30 bar, T = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed in situ via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups. The structure of the diamine nucleophile was revealed to affect the reaction's selectivity, with the best yields for the cyclic products being obtained in the presence of (1S,2S)-(+)-cyclohexane-1,2-diamine (a) as the nucleophile, using either 5- or 7-iodoindole as the substrate. The reaction's selectivity was rationalized based on electronic structure calculations, which explain the effect of the diamine structure on the predominant formation of the cyclic products.

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Nitrones as Trapping Reagents of α,β‐Unsaturated Carbene Intermediates – [1,2]Oxazino[5,4‐b]indoles by a Platinum‐ Catalyzed Intermolecular [3+3] Cycloaddition

Cited by 36 publications

References 43 publications

Rhodium‐Catalyzed Cyclization of Diynes with Nitrones: A Formal [2+2+5] Approach to Bridged Eight‐Membered Heterocycles

Rhodium‐Catalyzed Cyclization of Diynes with Nitrones: A Formal [2+2+5] Approach to Bridged Eight‐Membered Heterocycles

Diverse Applications of Nitrones for the Synthesis of Heterocyclic Compounds

A novel Pd-catalysed sequential carbonylation/cyclization approach toward bis- N -heterocycles: rationalization by electronic structure calculations

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