Synthesis of Azabicyclo[3.1.1]heptenes Enabled by Catalyst-Controlled Annulations of Bicyclo[1.1.0]butanes with Vinyl Azides

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(27), С. 18565 - 18575

Опубликована: Июнь 27, 2024

Bridged bicyclic scaffolds are emerging bioisosteres of planar aromatic rings under the concept "escape from flatland". However, adopting this into exploration pyridines remains elusive due to challenge incorporating a N atom such bridged structures. Herein, we report practical routes for divergent synthesis 2- and 3-azabicyclo[3.1.1]heptenes (aza-BCHepes) as potential readily accessible vinyl azides bicyclo[1.1.0]butanes (BCBs) via two distinct catalytic annulations. The reactivity tailored with BCBs is key achieving transformations. Ti

Язык: Английский

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Switching between the [2π+2σ] and Hetero‐[4π+2σ] Cycloaddition Reactivity of Bicyclobutanes with Lewis Acid Catalysts Enables the Synthesis of Spirocycles and Bridged Heterocycles

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(29)

Опубликована: Май 11, 2024

Abstract The exploration of the complex chemical diversity bicyclo[n.1.1]alkanes and their use as benzene bioisosteres has garnered significant attention over past two decades. Regiodivergent syntheses thiabicyclo[4.1.1]octanes (S‐BCOs) highly substituted bicyclo[2.1.1]hexanes (BCHs) using a Lewis acid‐catalyzed formal cycloaddition bicyclobutanes (BCBs) 3‐benzylideneindoline‐2‐thione derivatives have been established. first hetero‐(4+3) BCBs, catalyzed by Zn(OTf) 2 , was achieved with broad substrate scope under mild conditions. In contrast, less electrophilic BCB ester undergoes Sc(OTf) 3 ‐catalyzed [2π+2σ] reaction 1,1,2‐trisubstituted alkenes, yielding BCHs spirocyclic quaternary carbon center. Control experiments preliminary theoretical calculations suggest that diastereoselective product formation may involve concerted between zwitterionic intermediate E ‐1,1,2‐trisubstituted alkenes. Additionally, nucleophilic ring‐opening mechanism.

Язык: Английский

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Lewis Acid Catalyzed Cycloaddition of Bicyclobutanes with Ynamides for the Synthesis of Polysubstituted 2‐Amino‐bicyclo[2.1.1]hexenes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(32)

Опубликована: Май 24, 2024

Abstract Synthesis of bicyclic scaffolds has gained significant attention in drug discovery due to their potential mimic benzene bioisosteres. Here, we present a mild and scalable Sc(OTf) 3 ‐catalyzed [3+2] cycloaddition bicyclo[1.1.0]butanes (BCBs) with ynamides, yielding diverse array polysubstituted 2‐amino‐bicyclo[2.1.1]hexenes good excellent yields. These products offer valuable starting materials for the construction novel functionalized bicyclo[1.1.0]butanes. Preliminary mechanistic studies indicate that reaction involves nucleophilic addition ynamides bicyclo[1.1.0]butanes, followed by an intramolecular cyclization situ generated enolate keteniminium ion. We expect these findings will encourage utilization complex bioisosteres foster further investigation into BCB‐based chemistry.

Язык: Английский

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B(C₆F₅)₃-Catalyzed Formal (n + 3) (n = 5 and 6) Cycloaddition of Bicyclo[1.1.0]butanes to Medium Bicyclo[n.1.1]alkanes

Organic Letters, Год журнала: 2024, Номер 26(19), С. 4104 - 4110

Опубликована: Май 3, 2024

Herein, a B(C6F5)3-catalyzed formal (n + 3) = 5 and 6) cycloaddition of bicyclo[1.1.0]butanes (BCBs) with imidazolidines/hexahydropyrimidines is described. The reaction provides modular, atom-economical, efficient strategy to two libraries synthetically challenging medium-bridged rings, 2,5-diazabicyclo[5.1.1]nonanes 2,6-diazabicyclo[6.1.1]decanes, in moderate excellent yields. This also features simple operation, mild conditions, broad substrate scope. A scale-up experiment various synthetic transformations products further highlight the utility.

Язык: Английский

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Palladium-catalyzed decarboxylative (4 + 3) cycloadditions of bicyclobutanes with 2-alkylidenetrimethylene carbonates for the synthesis of 2-oxabicyclo[4.1.1]octanes

Chemical Science, Год журнала: 2024, Номер 15(34), С. 13942 - 13948

Опубликована: Янв. 1, 2024

While cycloaddition reactions of bicyclobutanes (BCBs) have emerged as a potent method for synthesizing (hetero-)bicyclo[

Язык: Английский

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Enantioselective formal (3 + 3) cycloaddition of bicyclobutanes with nitrones enabled by asymmetric Lewis acid catalysis

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Сен. 12, 2024

Язык: Английский

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Zinc‐Catalyzed Enantioselective Formal (3+2) Cycloadditions of Bicyclobutanes with Imines: Catalytic Asymmetric Synthesis of Azabicyclo[2.1.1]hexanes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(48)

Опубликована: Сен. 2, 2024

Abstract The cycloaddition reaction involving bicyclo[1.1.0]butanes (BCBs) offers a versatile and efficient synthetic platform for producing C(sp 3 )‐rich rigid bridged ring scaffolds, which act as phenyl bioisosteres. However, there is scarcity of catalytic asymmetric cycloadditions BCBs to fulfill the need enantioenriched saturated bicycles in drug design development. In this study, an synthesis valuable azabicyclo[2.1.1]hexanes (aza‐BCHs) by enantioselective zinc‐catalyzed (3+2) with imines reported. proceeds effectively novel type BCB that incorporates 2‐acyl imidazole group diverse array alkynyl‐ aryl‐substituted imines. target aza‐BCHs, consist α‐chiral amine fragments two quaternary carbon centers, are efficiently synthesized up 94 % 96.5:3.5 er under mild conditions. Experimental computational studies reveal follows concerted nucleophilic ring‐opening mechanism This distinct from previous on Lewis acid‐catalyzed BCBs.

Язык: Английский

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Divergent Synthesis of Sulfur‐Containing Bridged Cyclobutanes by Lewis Acid Catalyzed Formal Cycloadditions of Pyridinium 1,4‐Zwitterionic Thiolates and Bicyclobutanes

Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown

Опубликована: Май 31, 2024

Bridged cyclobutanes and sulfur heterocycles are currently under intense investigation as building blocks for pharmaceutical drug design. Two formal cycloaddition modes involving bicyclobutanes (BCBs) pyridinium 1,4-zwitterionic thiolate derivatives were described to rapidly expand the chemical space of sulfur-containing bridged cyclobutanes. By using Ni(ClO

Язык: Английский

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Facile access to bicyclo[2.1.1]hexanes by Lewis acid-catalyzed formal cycloaddition between silyl enol ethers and bicyclo[1.1.0]butanes

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Июль 20, 2024

Abstract Saturated three-dimensional carbocycles have gained increasing prominence in synthetic and medicinal chemistry. In particular, bicyclo[2.1.1]hexanes (BCHs) been identified as the molecular replacement for benzenes. Here, we present facile access to a variety of BCHs via stepwise two-electron formal (3 + 2) cycloaddition between silyl enol ethers bicyclo[1.1.0]butanes (BCBs) under Lewis acid catalysis. The reaction features wide functional group tolerance ethers, allowing efficient construction two vicinal quaternary carbon centers silyl-protected tertiary alcohol unit streamlined fashion. Interestingly, with conjugated dienol can provide bicyclo[4.1.1]octanes (BCOs) equipped that facilitate further transformation. utilities this methodology are demonstrated by late-stage modification natural products, transformations units on bicyclo[2.1.1]hexane frameworks, derivatization bicyclo[4.1.1]octanes, delivering functionalized bicycles traditionally inaccessible.

Язык: Английский

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Access to spiro-bicyclo[2.1.1]hexanes via BF₃·Et₂O-catalyzed formal [2π + 2σ] cycloaddition of bicyclo[1.1.0]butanes with benzofuran-derived oxa(aza)dienes

Organic Chemistry Frontiers, Год журнала: 2024, Номер 11(16), С. 4539 - 4545

Опубликована: Янв. 1, 2024

Rapid access to diverse spiro[benzofuran-2,2′-bicyclo[2.1.1]hexanes] via BF 3 ·Et 2 O-catalyzed [2π + 2σ] cycloaddition of bicyclo[1.1.0]butanes with readily available benzofuran-derived oxa(aza)dienes.

Язык: Английский

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