C(sp²)–H cyclobutylation of hydroxyarenes enabled by silver-π-acid catalysis: diastereocontrolled synthesis of 1,3-difunctionalized cyclobutanes

Chemical Science, Journal Year: 2023, Volume and Issue: 14(36), P. 9696 - 9703

Published: Jan. 1, 2023

Ring-opening of bicyclo[1.1.0]butanes (BCBs) is emerging as a powerful strategy for 1,3-difunctionalized cyclobutane synthesis. However, reported radical strain-release reactions are typically plagued with diastereoselectivity issues. Herein, an atom-economic protocol the highly chemo- and diastereoselective polar ring-opening BCBs hydroxyarenes catalyzed by π-acid catalyst AgBF4 has been developed. The use readily available starting materials, low loading, high selectivity (up to >98 : 2 d.r.), broad substrate scope, ease scale-up, versatile functionalizations products make this approach very attractive synthesis 1,1,3-trisubstituted cyclobutanes. Moreover, control experiments theoretical calculations were performed illustrate reaction mechanism selectivity.

Language: Английский

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Silver‐Enabled Cycloaddition of Bicyclobutanes with Isocyanides for the Synthesis of Polysubstituted 3‐Azabicyclo[3.1.1]heptanes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(21)

Published: March 5, 2024

Abstract Synthesis of bicyclic scaffolds has emerged as an important research topic in modern drug development because they can serve saturated bioisosters to enhance the physicochemical properties and metabolic profiles candidates. Here we report a remarkably simple silver‐enabled strategy access polysubstituted 3‐azabicyclo[3.1.1]heptanes single operation from readily accessible bicyclobutanes (BCBs) isocyanides. The process is proposed involve formal (3+3)/(3+2)/retro‐(3+2) cycloaddition sequence. This novel protocol allows for rapid generation molecular complexity starting materials, products be easily derivatized, further enriching BCB chemistry growing set valuable sp 3 ‐rich building blocks.

Language: Английский

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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, Journal Year: 2024, Volume and Issue: 146(27), P. 18565 - 18575

Published: June 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

Language: 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, Journal Year: 2024, Volume and Issue: 63(29)

Published: May 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.

Language: Английский

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Catalytic Asymmetric Construction of Chiral Polysubstituted 3-Azabicyclo[3.1.1]heptanes by Copper-Catalyzed Stereoselective Formal [4π+2σ] Cycloaddition

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(30), P. 21069 - 21077

Published: July 16, 2024

The direct construction of bioisosteric compounds enriched in C

Language: Английский

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Reaction Paradigms that Leverage Cycloaddition and Ring Strain to Construction Bicyclic Aryl Bioisosteres from Bicyclo[1.1.0]butanes

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 13(5)

Published: Feb. 21, 2024

Abstract Within a medicinal chemist's toolbox, one of the most effective strategies to improve overall properties biologically active compound is bioisosteric replacement. Ever since first example replacing benzene with bicyclo[1.1.1]pentane (BCP) group was published in late 1990s, [1] chemistry community has continually been expanding scope such phenyl replacements. Recent interest from academia focused on novel synthetic access C( sp 3 )‐rich bicyclic hydrocarbons expanded ring sizes. Herein, we summarize some these transformations and reveal that rely strain releasing cycloadditions bicyclo[1.1.0]butane (BCB) bicyclo[2.1.0]pentane (housane). We have organized this review based mechanism release strategies, namely, carbene cycloadditions, energy transfer photocatalyzed electron catalyzed polar cycloadditions.

Language: Английский

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Light‐Driven Synthesis and Functionalization of Bicycloalkanes, Cubanes and Related Bioisosteres

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(14)

Published: Jan. 5, 2024

Bicycloalkanes, cubanes and their structural analogues have emerged as bioisosteres of (hetero)arenes. To meet increasing demand, the chemical community has developed a plethora novel synthetic methods. In this review, we assess progress made in field light-driven construction functionalization such relevant molecules. We focused on diverse targets, well reaction processes giving access to: (i) [1.1.1]-bicyclopentanes (BCPs); (ii) [2.2.1]-bicyclohexanes (BCHs); (iii) [3.1.1]-bicycloheptanes (BCHeps); (iv) cubanes; other structurally related scaffolds. Finally, future perspectives dealing with identification manifolds to new functionalized bioisosteric units are discussed.

Language: Английский

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Bicyclo[1.1.0]butyl Radical Cations: Synthesis and Application to [2π + 2σ] Cycloaddition Reactions

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(23), P. 16237 - 16247

Published: May 29, 2024

As the chemistry that surrounds field of strained hydrocarbons, such as bicyclo[1.1.0]butane, continues to expand, it becomes increasingly advantageous develop alternative reactivity modes harness their unique properties access new regions chemical space. Herein, we report use photoredox catalysis promote single-electron oxidation bicyclo[1.1.0]butanes. The synthetic utility resulting radical cations is highlighted by ability undergo highly regio- and diastereoselective [2π + 2σ] cycloaddition reactions. most notable feature this transformation breadth alkene classes can be employed, including nonactivated alkenes, which have so far been elusive for previous strategies. A rigorous mechanistic investigation, in conjunction with DFT computation, was undertaken order better understand physical nature bicyclo[1.1.0]butyl thus provides a platform from further studies into applications these intermediates built upon.

Language: Английский

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Strain-release transformations of bicyclo[1.1.0]butanes and [1.1.1]propellanes

Tetrahedron Chem, Journal Year: 2024, Volume and Issue: 9, P. 100070 - 100070

Published: Feb. 28, 2024

Bicyclo[1.1.0]butanes (BCBs) and [1.1.1]propellanes (tricyclo[1.1.1.01,3]pentanes, TCPs) are structurally unique compounds with different chemical properties. Strain-release driven reactions have emerged as an atom- step-economic strategy for the organic synthesis. Using this strategy, a variety of functional ring molecules been efficiently synthesized, including various cyclobutane molecules, bicyclo[2.1.1]hexanes, bicyclo[1.1.1]pentanes, others. More specifically, these strain release-driven include aspects nucleophilic addition, radical electrophilic or transition metal catalysis. This review will discuss recent developments in strain-release transformations bicyclo[1.1.0]butanes [1.1.1]propellanes.

Language: 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, Journal Year: 2024, Volume and Issue: 63(32)

Published: May 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.

Language: Английский

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