Direct excitation of carbonyl cyclopropanes: From divergent pho-to-isomerization and annulation to unified reductive C-C cleavage DOI Creative Commons
Tin V. T. Nguyen, André Bossonnet, Duncan K. Brownsey

et al.

Published: May 21, 2024

We report herein our studies on the direct photoactivation of carbonyl cyclopropanes to give biradical intermediates, leading selective cleavage more substituted carbon-carbon bond. Depending substrate structure, extended alkenes were isolated or directly reacted in a photo-Nazarov process bicyclic products. Based these results, unified reductive ring-opening reaction was developed by using diphenyl disulfide as HAT reagent. By performing sequential cyclopropanation/selective ring opening reaction, we achieved CH2 insertion into ,- bond both acyclic and cyclic un-saturated compounds. Our protocol therefore provides further tool for framework-editing carbocycles, com-plementing recent progress "skeletal editing" strategies.

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
ortho-Selective Dearomative [2π + 2σ] Photocycloadditions of Bicyclic Aza-Arenes DOI

Roman Kleinmans,

Subhabrata Dutta,

Kristers Ozols

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(22), P. 12324 - 12332

Published: May 26, 2023

Dearomative photocycloadditions are valuable chemical transformations, serving as an efficient platform to create three-dimensional molecular complexity. However, the photolability of original addition product especially within context ortho cycloadditions often causes undesired consecutive rearrangements, rendering these cycloadducts elusive. Herein, we report ortho-selective intermolecular photocycloaddition bicyclic aza-arenes including (iso)quinolines, quinazolines, and quinoxalines by utilizing a strain-release approach. With bicyclo[1.1.0]butanes coupling partners, this dearomative [2π + 2σ] cycloaddition enables straightforward construction C(sp3)-rich bicyclo[2.1.1]hexanes directly connected N-heteroarenes. Photophysical experiments DFT calculations revealed origin selectivity indicate that, in originally proposed energy transfer or direct excitation pathways, chain reaction mechanism is operative depending on conditions.

Language: Английский

Citations

124
Photocatalyzed [2σ + 2σ] and [2σ + 2π] Cycloadditions for the Synthesis of Bicyclo[3.1.1]heptanes and 5- or 6-Membered Carbocycles DOI
Tin V. T. Nguyen, André Bossonnet, Matthew D. Wodrich

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(46), P. 25411 - 25421

Published: Nov. 7, 2023

We report the use of photocatalysis for homolytic ring-opening carbonyl cyclopropanes. In contrast to previous studies, our approach does not require a metal cocatalyst or strong reductant. The cyclopropanes can be employed both [2σ + 2σ] and 2π] annulation with either alkenes/alkynes bicyclo[1.1.0]butanes, yielding cyclopent-anes/-enes bicyclo[3.1.1]heptanes (BCHs), respectively. BCHs are promising bioisosteres 1,2,4,5 tetra-substituted aromatic rings. Mechanistic including density functional theory computation trapping experiment DMPO, support 1,3-biradical generated from cyclopropane as key intermediate these transformations.

Language: Английский

Citations

94
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
Rejuvenation of dearomative cycloaddition reactions via visible light energy transfer catalysis DOI Creative Commons

Angshuman Palai,

Pramod Rai,

Biplab Maji

et al.

Chemical Science, Journal Year: 2023, Volume and Issue: 14(43), P. 12004 - 12025

Published: Jan. 1, 2023

Dearomative cycloaddition is a powerful technique to access sp

Language: Английский

Citations

34
Photosensitized [4+2]‐ and [2+2]‐Cycloaddition Reactions of N‐Sulfonylimines DOI Creative Commons

Wang Wang,

M. Kevin Brown

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: July 3, 2023

Abstract The synthesis of polycyclic compounds is high interest due to the prevalence these motifs in drugs and natural products. Herein, we report on stereoselective construction 3D bicyclic scaffolds azetidine derivatives by modulation N ‐sulfonylimines achieve either [4+2]‐ or [2+2]‐cycloaddition reactions. utility method was established further product. Mechanistic studies are also included, which support reaction via Dexter energy transfer.

Language: Английский

Citations

25
Photo-induced intramolecular dearomative [5 + 4] cycloaddition of arenes for the construction of highly strained medium-sized-rings DOI Creative Commons
Min Zhu, Yuanjun Gao,

Xu‐Lun Huang

et al.

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: March 19, 2024

Abstract Medium-sized-ring compounds have been recognized as challenging synthetic targets in organic chemistry. Especially, the difficulty of synthesis will be augmented if an E -olefin moiety is embedded. Recently, photo-induced dearomative cycloaddition reactions that proceed via energy transfer mechanism witnessed significant developments and provided powerful methods for transformations are not easily realized under thermal conditions. Herein, we report intramolecular [5 + 4] naphthalene-derived vinylcyclopropanes visible-light irradiation a proper triplet photosensitizer. The reaction affords dearomatized polycyclic molecules possessing nine-membered-ring with good yields (up to 86%) stereoselectivity 8.8/1 / Z ). Detailed computational studies reveal origin behind favorable formation thermodynamically less stable isomers. Diverse derivations products also demonstrated.

Language: Английский

Citations

10
Synthesis of 2‐Azanorbornanes via Strain‐Release Formal Cycloadditions Initiated by Energy Transfer DOI Creative Commons

Yu‐Che Chang,

Christophe Salomé, Thomas C. Fessard

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(51)

Published: Nov. 14, 2023

Rigid bicycles are becoming more popular in the pharmaceutical industry because they allow for expansion to new and unique chemical spaces. This work describes a strategy construct 2-azanorbornanes, which can act as rigid piperidine/pyrrolidine scaffolds with well-defined exit vectors. To achieve synthesis of strain-release reagent, azahousane, is introduced along its photosensitized formal cycloaddition alkenes. Furthermore, reactivity between housane an imine disclosed. Both strategies lead various substituted 2-azanorbornanes good selectivities.

Language: Английский

Citations

20
Skeletal Transformation of Unactivated Arenes Enabled by a Low-Temperature Dearomative (3 + 2) Cycloaddition DOI
Sajan Pradhan, Fahimeh Mohammadi, Jean Bouffard

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(22), P. 12214 - 12223

Published: May 24, 2023

Simple aromatic compounds like benzene are abundant feedstocks, for which the preparation of derivatives chiefly begins with electrophilic substitution reactions or, less frequently, reductions. Their high stability makes them particularly reluctant to participate in cycloadditions under ordinary reaction conditions. Here, we demonstrate exceptional ability 1,3-diaza-2-azoniaallene cations undergo formal (3 + 2) unactivated below room temperature, providing thermally stable dearomatized adducts on a multi-gram scale. The cycloaddition, tolerates polar functional groups, activates ring toward further elaboration. On treatment dienophiles, cycloadducts (4 cycloaddition–cycloreversion cascade yield substituted or fused arenes, including naphthalene derivatives. overall sequence results transmutation arenes through an exchange carbons: two-carbon fragment from original is replaced another incoming dienophile, introducing unconventional disconnection synthesis ubiquitous building blocks. Applications this two-step acenes, isotopically labeled molecules, and medicinally relevant demonstrated.

Language: Английский

Citations

18
Catalytic asymmetric [4 + 2] dearomative photocycloadditions of anthracene and its derivatives with alkenylazaarenes DOI Creative Commons
Dong Tian,

Wenshuo Shi,

Xin Sun

et al.

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: May 29, 2024

Abstract Photocatalysis through energy transfer has been investigated for the facilitation of [4 + 2] cycloaddition reactions. However, high reactivity radical species poses a challenging obstacle to achieving enantiocontrol with chiral catalysts, as no enantioselective examples have reported thus far. Here, we present development catalytic asymmetric dearomative photocycloaddition involving anthracene and its derivatives alkenylazaarenes. This accomplishment is achieved by utilizing cooperative photosensitizer Brønsted acid catalysis platform. Importantly, this process enables activation substrates from triplet DPZ, thereby initiating precise stereoselective sequential transformation. The significance our work highlighted synthesis diverse range pharmaceutical valuable cycloadducts incorporating attractive azaarenes, all obtained yields, ees, drs. broad substrate scope further underscored successful construction all-carbon quaternary stereocenters adjacent stereocenters.

Language: Английский

Citations

7