Stereoselective Alder-Ene Reactions of Bicyclo[1.1.0]butanes: Facile Synthesis of Cyclopropyl- and Aryl-Substituted Cyclobutenes DOI Creative Commons
Ayan Dasgupta, Subrata Bhattacharjee,

Zixuan Tong

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 146(1), P. 1196 - 1203

Published: Dec. 29, 2023

Bicyclo[1.1.0]butanes (BCBs), strained carbocycles comprising two fused cyclopropane rings, have become well-established building blocks in organic synthesis, medicinal chemistry, and chemical biology due to their diverse reactivity profile with radicals, nucleophiles, cations, carbenes. The constraints of the bicyclic ring system confer high p-character on interbridgehead C–C bond, leading this broad reaction profile; however, use BCBs pericyclic processes has date been largely overlooked favor such stepwise, non-concerted additions. Here, we describe as substrates for ene-like reactions alkenes alkynes, which give rise cyclobutenes decorated highly substituted cyclopropanes arenes. former products are obtained from stereoselective cyclopropenes, generated situ vinyl diazoacetates under blue light irradiation (440 nm). Cyclobutenes featuring a quaternary aryl-bearing carbon atom prepared equivalent arynes, proceed yields mild conditions. Mechanistic studies highlight importance electronic effects while computational investigations support concerted pathway rationalize excellent stereoselectivity cyclopropenes.

Language: Английский

Energy transfer photocatalysis: exciting modes of reactivity DOI
Subhabrata Dutta, Johannes E. Erchinger, Felix Strieth‐Kalthoff

et al.

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(3), P. 1068 - 1089

Published: Jan. 1, 2024

Leveraging light energy to expose the ‘dark’ reactive states describes whole essence of triplet–triplet transfer. This offers an impressive opportunity conduct a multitude diverse reactions and access sought-after molecular motifs.

Language: Английский

Citations

144
Eu(OTf)3‐Catalyzed Formal Dipolar [4π+2σ] Cycloaddition of Bicyclo‐[1.1.0]butanes with Nitrones: Access to Polysubstituted 2‐Oxa‐3‐azabicyclo[3.1.1]heptanes DOI
Jian Zhang,

Jia‐Yi Su,

Hanliang Zheng

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(13)

Published: Jan. 30, 2024

Abstract Herein, we have synthesized multifunctionalized 2‐oxa‐3‐azabicyclo[3.1.1]heptanes, which are considered potential bioisosteres for meta ‐substituted arenes, through Eu(OTf) 3 ‐catalyzed formal dipolar [4π+2σ] cycloaddition of bicyclo[1.1.0]butanes with nitrones. This methodology represents the initial instance fabricating bicyclo[3.1.1]heptanes adorned multiple heteroatoms. The protocol exhibits both mild reaction conditions and a good tolerance various functional groups. Computational density theory calculations support that mechanism likely involves nucleophilic addition nitrones to bicyclo[1.1.0]butanes, succeeded by an intramolecular cyclization. synthetic utility this novel has been demonstrated in concise synthesis analogue Rupatadine.

Language: Английский

Citations

47
Palladium-Catalyzed Ligand-Controlled Switchable Hetero-(5 + 3)/Enantioselective [2σ+2σ] Cycloadditions of Bicyclobutanes with Vinyl Oxiranes DOI
Jin‐Lan Zhou, Yuanjiu Xiao,

Linke He

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(29), P. 19621 - 19628

Published: May 13, 2024

For nearly 60 years, significant research efforts have been focused on developing strategies for the cycloaddition of bicyclobutanes (BCBs). However, higher-order and catalytic asymmetric BCBs long-standing formidable challenges. Here, we report Pd-catalyzed ligand-controlled, tunable cycloadditions divergent synthesis bridged bicyclic frameworks. The dppb ligand facilitates formal (5+3) vinyl oxiranes, yielding valuable eight-membered ethers with scaffolds in 100% regioselectivity. Cy-DPEphos promotes selective hetero-[2σ+2σ] to access pharmacologically important 2-oxabicyclo[3.1.1]heptane (O-BCHeps). Furthermore, corresponding O-BCHeps 94–99% ee has achieved using chiral (S)-DTBM-Segphos, representing first cross-dimerization two strained rings. obtained are promising bioisosteres ortho-substituted benzenes.

Language: Английский

Citations

46
Three-dimensional saturated C(sp3)-rich bioisosteres for benzene DOI
Jet Tsien, Chao Hu, Rohan R. Merchant

et al.

Nature Reviews Chemistry, Journal Year: 2024, Volume and Issue: 8(8), P. 605 - 627

Published: July 9, 2024

Language: Английский

Citations

45
Silver‐Enabled Cycloaddition of Bicyclobutanes with Isocyanides for the Synthesis of Polysubstituted 3‐Azabicyclo[3.1.1]heptanes DOI
Yujie Liang, Ronewa Nematswerani, Constantin G. Daniliuc

et al.

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

Citations

43
Double Strain-Release [2π+2σ]-Photocycloaddition DOI
Subhabrata Dutta, Yilin Lu, Johannes E. Erchinger

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(8), P. 5232 - 5241

Published: Feb. 13, 2024

In pursuit of potent pharmaceutical candidates and to further improve their chemical traits, small ring systems can serve as a potential starting point. Small units have the additional merit loaded strain at core, making them suitable reactants they capitalize on this intrinsic driving force. With introduction cyclobutenone strained precursor ketene, photocycloaddition with another unit, bicyclo[1.1.0]butane (BCB), enables reactivity both π-units in transient ketene. This double strain-release driven [2π+2σ]-photocycloaddition promotes synthesis diverse heterobicyclo[2.1.1]hexane units, pharmaceutically relevant bioisostere. The effective under catalyst-free conditions high functional group tolerance defines its synthetic utility. Experimental mechanistic studies density theory (DFT) calculations suggest that takes place via triplet mechanism.

Language: Английский

Citations

42
Synthesis of Azabicyclo[3.1.1]heptenes Enabled by Catalyst-Controlled Annulations of Bicyclo[1.1.0]butanes with Vinyl Azides DOI

Zhongren Lin,

Haosong Ren,

Xinbo Lin

et al.

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

Citations

41
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 DOI
Jijie Wang, Lei Tang, Yuanjiu Xiao

et al.

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

Citations

37
Catalytic Asymmetric Construction of Chiral Polysubstituted 3-Azabicyclo[3.1.1]heptanes by Copper-Catalyzed Stereoselective Formal [4π+2σ] Cycloaddition DOI

Xunhua Wang,

Rongkai Gao,

Xiaoxun Li

et al.

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

Citations

33
Reaction Paradigms that Leverage Cycloaddition and Ring Strain to Construction Bicyclic Aryl Bioisosteres from Bicyclo[1.1.0]butanes DOI

Stephen J. Sujansky,

Xiaoshen Ma

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

Citations

30