A new synthetic application of vinyl aziridines as N‐containing three‐atom components in a rhodium‐catalyzed 4+3 cycloaddition reaction is described. The reaction proceeds well with various silyl ...dienol ethers and vinyl aziridines, and enables the efficient synthesis of highly functionalized azepines in an enantioselective manner with net inversion of absolute configuration. The salient features of the transformation include the use of readily available substrates, high selectivity, and mild reaction conditions, as well as the versatile functionalization of the products.
Strike a happy medium: The title reaction, in which the vinyl aziridine acts as an aza‐three‐atom component, provided highly functionalized azepines in an enantioselective manner with net inversion of configuration (see scheme; Si is a silyl protecting group). This strategy features the use of readily available substrates, high selectivity, mild reaction conditions, ease of scale‐up, and versatile functionalization of the products.
For the first time, a gold‐catalyzed 4+3 cycloaddition/C–H functionalization cascade was developed. This reaction provides efficient access to densely functionalized cycloheptabindoles, in which a ...second propargylic ester is incorporated as a side chain, in excellent yields. By hydrolysis of the two vinyl acetates, highly functionalized indole‐fused bicyclo3.2.1octane derivatives bearing four contiguous stereogenic centers were acquired as single regio‐ and diastereomers through an additional intramolecular transannular aldol reaction. On the basis of the above two transformations, an economical “one‐pot”, three‐step cascade reaction was developed.
A gold‐catalyzed 4+3 cycloaddition/C–H functionalization cascade to synthesize densely functionalized cycloheptabindoles is described; furthermore, a “one‐pot” cascade transformation of some representative products into highly functionalized indole‐fused bicyclo3.2.1octane derivatives containing four contiguous stereogenic centers by successive hydrolysis and aldol reactions is also presented.
The first rhodium‐catalyzed intermolecular 3+2 cycloaddition reaction of vinyl aziridines and allenes for the synthesis of enantioenriched functionalized pyrrolidines was realized. 3+2 cycloaddition ...with the proximal C=C bond of N‐allenamides gave 3‐methylene‐pyrrolidines in high regio‐ and diastereoselectivity, whereas, 2‐methylene‐pyrrolidines were obtained as the major products by the cycloadditions of vinyl aziridines with the distal C=C bond of allenes. Use of readily available starting materials, a broad substrate scope, high selectivity, mild reaction conditions, as well as versatile functionalization of the cycloadducts make this approach very practical and attractive.
Adding together rapidly: A regiodivergent synthesis of enantioenriched functionalized pyrrolidines, such as 2‐methylene‐ and 3‐methylene‐pyrrolidines, has been developed through a regioselective 3+2 cycloaddition of vinyl aziridines with allenes and N‐alleneamines, respectively. The reaction demonstrates general substrate scope, mild conditions, atom‐economy, and proceeds with complete chirality transfer.
The control of reaction pathways for selective and enantiospecific synthesis of functionalized pyrrolidines and γ-amino ketones has been realized. Rhodium-catalyzed 3+2 cycloadditions of ...vinylaziridines and enolsilanes with a bulky silyl group gave functionalized pyrrolidines with moderate to excellent diastereoselectivities, while the reaction of silyl enol ethers with a less bulky silyl group afforded chiral γ-amino ketones in good yields.
Catalyst-controlled divergent intermolecular cycloadditions of vinylaziridines with alkynes have been developed. By using Rh(NBD)2BF4 as the catalyst, a 3 + 2 cycloaddition reaction was achieved ...with broad substrate scope and high stereoselectivity under mild reaction conditions. Moreover, the chirality of vinylaziridines can be completely transferred to the 3 + 2 cycloadducts. When the catalyst was changed to Rh(η6-C10H8) (COD)SbF6, the alternative 5 + 2 cycloadducts were selectively formed under otherwise identical conditions.
An atom-economic route to ring-fused 1,2,4-hexahydrotriazines relying upon a new synthetic application of vinylaziridines in a rhodium-catalyzed intermolecular 3+3 cycloaddition of C,N-cyclic ...azomethine imines has been reported. Highly efficient chirality transfer in the present transformation was also observed, providing a new method for the synthesis of sp
-carbon-rich 1,2,4-hexahydrotriazines in an enantioselective manner.
The enantioselective construction of densely functionalized cyclopentene bearing contiguous three stereocenters has been a challenging task in organic synthesis. Herein, we present a ...phoshine-catalyzed highly regio-, diastereo- and enantioselective 3 + 2 cycloaddition of γ-substituted allenoates with β-perfluoroalkyl enones, delivering a wide range of densely functionalized perfluoroalkylated cyclopentenes with three contiguous chiral stereocenters.
A new synthetic application of vinyl aziridines as N‐containing three‐atom components in a rhodium‐catalyzed 4+3 cycloaddition reaction is described. The reaction proceeds well with various silyl ...dienol ethers and vinyl aziridines, and enables the efficient synthesis of highly functionalized azepines in an enantioselective manner with net inversion of absolute configuration. The salient features of the transformation include the use of readily available substrates, high selectivity, and mild reaction conditions, as well as the versatile functionalization of the products.
Breite Auswahl: Die Titelreaktion, in der Vinylaziridine als eine dreiatomige Aza‐Komponente agieren, liefert hoch funktionalisierte Azepine in enantioselektiver Weise und unter Inversion der Konfiguration (siehe Schema; Si=Silylschutzgruppe). Die Strategie zeichnet sich durch leicht verfügbare Substrate, hohe Selektivität, milde Reaktionsbedingungen, einfache Skalierung und vielseitige Funktionalisierung der Produkte aus.
The first rhodium‐catalyzed intermolecular 3+2 cycloaddition reaction of vinyl aziridines and allenes for the synthesis of enantioenriched functionalized pyrrolidines was realized. 3+2 cycloaddition ...with the proximal C=C bond of N‐allenamides gave 3‐methylene‐pyrrolidines in high regio‐ and diastereoselectivity, whereas, 2‐methylene‐pyrrolidines were obtained as the major products by the cycloadditions of vinyl aziridines with the distal C=C bond of allenes. Use of readily available starting materials, a broad substrate scope, high selectivity, mild reaction conditions, as well as versatile functionalization of the cycloadducts make this approach very practical and attractive.
Rasch zusammengebaut: Die regiodivergente Synthese von enantiomerenangereicherten funktionalisierten Pyrrolidinen wie 2‐Methylen‐ und 3‐Methylenpyrrolidinen greift auf eine regioselektive 3+2‐Cycloaddition von Vinylaziridinen an Allene bzw. N‐Allenamine zurück. Die Reaktion zeichnet sich durch einen universellen Substratbereich, milde Bedingungen, Atomökonomie und vollständigen Chiralitätstransfer aus.
The control of reaction pathways for selective and enantiospecific synthesis of functionalized pyrrolidines and γ-amino ketones has been realized. Rhodium-catalyzed 3+2 cycloadditions of ...vinylaziridines and enolsilanes with a bulky silyl group gave functionalized pyrrolidines with moderate to excellent diastereoselectivities, while the reaction of silyl enol ethers with a less bulky silyl group afforded chiral γ-amino ketones in good yields.
Rhodium-catalyzed enantiospecific intermolecular 3+2 cycloadditions and ring-opening reactions of vinylaziridines with silyl enol ethers have been developed to synthesize functionalized pyrrolidines and γ-amino ketones, respectively.
![Gold‐Catalyzed [4+3] Cycloa...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1434-193X/small "Gold‐Catalyzed [4+3] Cycloaddition/C–H Functionalization Cascade: Regio‐ and Diastereoselective Route to Cyclohepta[b]indoles")
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