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Patra A, Patalag LJ, Jones PG, Werz DB. Extended Benzene-Fused Oligo-BODIPYs: In Three Steps to a Series of Large, Arc-Shaped, Near-Infrared Dyes. Angew Chem Int Ed Engl 2021; 60:747-752. [PMID: 33022876 PMCID: PMC7839587 DOI: 10.1002/anie.202012335] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Indexed: 02/01/2023]
Abstract
We present a straightforward, three-step synthesis engaging an oligomerization and subsequent one-pot oxidation step to form fully conjugated, benzene-fused oligo-BODIPYs from simple BODIPY precursors. FeCl3 serves as an efficient, bifunctional oxidant for a (multiple) cyclization/desaturation process, applied to ethylene-bridged dimeric, trimeric and oligomeric species to transform linking ethano units into stiff benzene fusions between unsubstituted β-positions of each BODIPY unit. The structural integrity was verified by X-ray crystallography, and all target compounds were studied in detail by photophysical, electrochemical and computational means. The main S1 excited state gradually converges to a structure-specific excitation limit, displaying a strong shift of the absorption event from about 500 nm (BODIPY monomer) to 955 nm (octamer) with attenuation coefficients up to ca. 500 000 M-1 cm-1 .
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Kolb S, Oliver GA, Werz DB. Chemistry Evolves, Terms Evolve, but Phenomena Do Not Evolve: From Chalcogen-Chalcogen Interactions to Chalcogen Bonding. Angew Chem Int Ed Engl 2020; 59:22306-22310. [PMID: 32969111 DOI: 10.1002/anie.202007314] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Indexed: 11/08/2022]
Abstract
Chalcogen bonding is important in numerous aspects of chemistry, both in the solid state and in solution. Surveying the literature, it becomes clear that during its rebranding from chalcogen-chalcogen interactions, some parts of the community have somewhat neglected to recall its discovery and the initial studies referring to it in its previous guise. In this Viewpoint, we trace the path of research into this phenomenon, from its discovery, through its renaming, and to some of the varied and interesting chemistry it has led to so far, ranging from crystal engineering through supramolecular assembly to modern catalysis.
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Kolb S, Oliver GA, Werz DB. Chemie und Begriffe entwickeln sich, aber Phänomene nicht: Von Chalkogen‐Chalkogen‐Wechselwirkungen zu “Chalcogen Bonding”. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007314] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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54
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Jacob A, Jones PG, Werz DB. (3 + 2)-Cycloaddition of Donor–Acceptor Cyclopropanes with Selenocyanate: Synthesis of Dihydroselenophenes and Selenophenes. Org Lett 2020; 22:8720-8724. [DOI: 10.1021/acs.orglett.0c03329] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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55
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Chiodini S, Ruiz-Rincón S, Garcia PD, Martin S, Kettelhoit K, Armenia I, Werz DB, Cea P. Bottom Effect in Atomic Force Microscopy Nanomechanics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2000269. [PMID: 32761794 DOI: 10.1002/smll.202000269] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 06/04/2020] [Indexed: 05/27/2023]
Abstract
In this work, the influence of the rigid substrate on the determination of the sample Young's modulus, the so-called bottom-effect artifact, is demonstrated by an atomic force microscopy force-spectroscopy experiment. The nanomechanical properties of a one-component supported lipid membrane (SLM) exhibiting areas of two different thicknesses are studied: While a standard contact mechanics model (Sneddon) provides two different elastic moduli for these two morphologies, it is shown that Garcia's bottom-effect artifact correction yields a unique value, as expected for an intrinsic material property. Remarkably, it is demonstrated that the ratio between the contact radius (and not only the indentation) and the sample thickness is the key parameter addressing the relevance of the bottom-effect artifact. The experimental results are validated by finite element method simulations providing a solid support to Garcia's theory. The amphiphilic nature of the investigated material is representative of several kinds of lipids, suggesting that the results have far reaching implications for determining the correct Young's modulus of SLMs. The generality of Garcia's bottom-effect artifact correction allows its application to every kind of supported soft film.
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Petzold M, Günther A, Jones PG, Werz DB. Regio- and Diastereoselective Dimerization of Diazo Carbonyls: A Cooperative Catalytic Approach to Complex Scaffolds with Four Contiguous Stereocenters. Chemistry 2020; 26:11119-11123. [PMID: 32237096 PMCID: PMC7497023 DOI: 10.1002/chem.202001548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Indexed: 12/20/2022]
Abstract
Starting from readily available o-diazoacyl-substituted arene carboxylates, scaffolds with the 5,9-epoxycyclohepta[b]pyran-2(3H)-one core were obtained by cooperative RhII , Lewis and Brønsted acid catalysis. Four new bonds, three functional groups (lactone, ketal, and alcohol) and four contiguous stereocenters are formed during this regio- and diastereoselective process in a single synthetic step. Intensive optimization and mechanistic studies, including the trapping, isolation, and elucidation of reaction intermediates, led to a plausible mechanistic scenario. The reaction is proposed to involve carbonyl ylides but also transient species of the ketocarbene equilibrium that undergo a cascade of cycloaddition and skeletal rearrangements.
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Ahlburg NL, Jones PG, Werz DB. cis-Selective, Enantiospecific Addition of Donor-Acceptor Cyclopropanes to Activated Alkenes: An Iodination/Michael-Cyclization Cascade. Org Lett 2020; 22:6404-6408. [PMID: 32806195 DOI: 10.1021/acs.orglett.0c02210] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We present a versatile method for the enantiospecific, cis-diastereoselective intermolecular and intramolecular cycloaddition of donor-acceptor cyclopropanes to electron-poor alkenes with cyclic acceptor groups to afford highly substituted spirocyclopentanes in good to excellent yields. The reaction can be applied to biologically interesting scaffolds, including barbiturates and isoxazolones. Mechanistic investigations were undertaken to explain the unusual diastereoselectivity and enantiospecificity; these suggest an iodination/Michael-cyclization cascade.
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Bürger M, Röttger SH, Loch MN, Jones PG, Werz DB. Pd-Catalyzed Cyanoselenylation of Internal Alkynes: Access to Tetrasubstituted Selenoenol Ethers. Org Lett 2020; 22:5025-5029. [PMID: 32610926 DOI: 10.1021/acs.orglett.0c01582] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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59
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Schubert T, Sych T, Madl J, Xu M, Omidvar R, Patalag LJ, Ries A, Kettelhoit K, Brandel A, Mely Y, Steinem C, Werz DB, Thuenauer R, Römer W. Differential recognition of lipid domains by two Gb3-binding lectins. Sci Rep 2020; 10:9752. [PMID: 32546842 PMCID: PMC7297801 DOI: 10.1038/s41598-020-66522-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 05/20/2020] [Indexed: 12/19/2022] Open
Abstract
The two lectins LecA from Pseudomonas aeruginosa and the B-subunit of Shiga toxin from Shigella dysenteriae (StxB) share the glycosphingolipid globotriaosylceramide (Gb3) as receptor. Counterintuitively, we found that LecA and StxB segregated into different domains after recognizing Gb3 at the plasma membrane of cells. We hypothesized that the orientation of the carbohydrate head group of Gb3 embedded in the lipid bilayer differentially influences LecA and StxB binding. To test this hypothesis, we reconstituted lectin-Gb3 interaction using giant unilamellar vesicles and were indeed able to rebuild LecA and StxB segregation. Both, the Gb3 fatty acyl chain structure and the local membrane environment, modulated Gb3 recognition by LecA and StxB. Specifically, StxB preferred more ordered membranes compared to LecA. Based on our findings, we propose comparing staining patterns of LecA and StxB as an alternative method to assess membrane order in cells. To verify this approach, we re-established that the apical plasma membrane of epithelial cells is more ordered than the basolateral plasma membrane. Additionally, we found that StxB recognized Gb3 at the primary cilium and the periciliary membrane, whereas LecA only bound periciliary Gb3. This suggests that the ciliary membrane is of higher order than the surrounding periciliary membrane.
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Mlostoń G, Kowalczyk M, Augustin AU, Jones PG, Werz DB. Ferrocenyl-substituted tetrahydrothiophenes via formal [3 + 2]-cycloaddition reactions of ferrocenyl thioketones with donor-acceptor cyclopropanes. Beilstein J Org Chem 2020; 16:1288-1295. [PMID: 32566031 PMCID: PMC7296194 DOI: 10.3762/bjoc.16.109] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 05/27/2020] [Indexed: 12/13/2022] Open
Abstract
Ferrocenyl thioketones reacted with donor-acceptor cyclopropanes in dichloromethane at room temperature in the presence of catalytic amounts of Sc(OTf)3 yielding tetrahydrothiophene derivatives, products of formal [3 + 2]-cycloaddition reactions, in moderate to high yields. In all studied cases, dimethyl 2-arylcyclopropane dicarboxylates reacted with the corresponding aryl ferrocenyl thioketones in a completely diastereoselective manner to form single products in which (C-2)-Ar and (C-5)-ferrocenyl groups were oriented in a cis-fashion. In contrast, the same cyclopropanes underwent reaction with alkyl ferrocenyl thioketones to form nearly equal amounts of both diastereoisomeric tetrahydrothiophenes. A low selectivity was also observed in the reaction of a 2-phthalimide-derived cyclopropane with ferrocenyl phenyl thioketone.
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Ahlburg NL, Velarde AR, Kieber-Emmons MT, Jones PG, Werz DB. Substituted Benzothietes: Synthesis and a Quantum Chemical Investigation of Their Cycloreversion Properties. Org Lett 2020; 22:4255-4260. [PMID: 32401521 DOI: 10.1021/acs.orglett.0c01261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A flexible synthesis for highly substituted benzothietes that does not require flash-vacuum pyrolysis was developed. This allows for the use of a number of functional groups and nonvaporizable molecules. Highly stabilized derivatives were isolated. The molecular orbital properties of various benzothietes were evaluated by density functional methods. The mechanism of the cycloreversion of the four-membered ring was compared to that of the oxygen-containing analogues.
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Reding A, Ohta N, Sebrantke P, Jones PG, Nakao Y, Werz DB. Intramolecular
trans
‐Carbocarbonation of Carbon‐Carbon Triple Bonds by an
anti
‐Carbopalladation/Suzuki Coupling Cascade. ChemCatChem 2020. [DOI: 10.1002/cctc.202000545] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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63
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Ahadi S, Awan SI, Werz DB. Total Synthesis of Tri-, Hexa- and Heptasaccharidic Substructures of the O-Polysaccharide of Providencia rustigianii O34. Chemistry 2020; 26:6264-6270. [PMID: 32092205 PMCID: PMC7318715 DOI: 10.1002/chem.202000496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/20/2020] [Indexed: 12/22/2022]
Abstract
A general and efficient strategy for synthesis of tri‐, hexa‐ and heptasaccharidic substructures of the lipopolysaccharide of Providencia rustigianii O34 is described. For the heptasaccharide seven different building blocks were employed. Special features of the structures are an α‐linked galactosamine and the two embedded α‐fucose units, which are either branched at positions‐3 and ‐4 or further linked at their 2‐position. Convergent strategies focused on [4+3], [3+4], and [4+2+1] couplings. Whereas the [4+3] and [3+4] coupling strategies failed the [4+2+1] strategy was successful. As monosaccharidic building blocks trichloroacetimidates and phosphates were employed. Global deprotection of the fully protected structures was achieved by Birch reaction.
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Lücht A, Kreft A, Jones PG, Werz DB. Ketenedithioacetals as Surrogates for the Formal Insertion of Ketenes into Donor–Acceptor Cyclopropanes. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000233] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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65
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Köllmann C, Sake SM, Jones PG, Pietschmann T, Werz DB. Protecting-Group-Mediated Diastereoselective Synthesis of C4'-Methylated Uridine Analogs and Their Activity against the Human Respiratory Syncytial Virus. J Org Chem 2020; 85:4267-4278. [PMID: 32036652 DOI: 10.1021/acs.joc.9b03425] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Adjusting the protecting group strategy, from an alkyl ether to a bidentate ketal at the carbohydrate backbone of uridine, facilitates a switchable diastereoselective α- or β-C4'/C5'-spirocyclopropanation. Using these spirocyclopropanated nucleosides as key intermediates, we synthesized a variety of C4'-methylated d-ribose and l-lyxose-configured uridine derivatives by a base-mediated ring-opening of the spirocyclopropanol moiety. Investigations of antiviral activity against the human respiratory syncytial virus were carried out for selected derivatives, showing moderate activity.
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Werz DB, Biju AT. Uncovering the Neglected Similarities of Arynes and Donor-Acceptor Cyclopropanes. Angew Chem Int Ed Engl 2020; 59:3385-3398. [PMID: 31529661 PMCID: PMC7065169 DOI: 10.1002/anie.201909213] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Indexed: 12/21/2022]
Abstract
Arynes and donor-acceptor (D-A) cyclopropanes are two classes of strained systems having the potential for numerous applications in organic synthesis. The last two decades have witnessed a renaissance of interest in the chemistry of these species primarily because of the mild and robust methods for their generation or activation. Commonly, arynes as easily polarizable systems result in 1,2-disubstitution, whereas D-A cyclopropanes as polarized systems lead to 1,3-bisfunctionalization thereby showing striking similarities. Transformations with 1,2- and 1,3-dipoles afford cyclic structures. With arynes, emerging four-membered rings as intermediates might react further, whereas the analogous five-membered rings obtained from D-A cyclopropanes are most often the final products. However, there are a few cases where these intermediates behave surprisingly differently. This Minireview highlights the parallels in reactivity between arynes and D-A cyclopropanes thereby shedding light on the neglected similarities of these two reactive species.
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Bürger M, Loch MN, Jones PG, Werz DB. From 1,2-difunctionalisation to cyanide-transfer cascades - Pd-catalysed cyanosulfenylation of internal (oligo)alkynes. Chem Sci 2019; 11:1912-1917. [PMID: 34123284 PMCID: PMC8148069 DOI: 10.1039/c9sc04569d] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Internal alkynes substituted by aliphatic or aromatic moieties or by heteroatoms were converted into sulphur-substituted acrylonitrile derivatives. Key is the use of Pd catalysis, which allows the addition of aromatic and aliphatic thiocyanates in an intra- and intermolecular manner. Substrates with several alkyne units underwent further carbopalladation steps after the initial thiopalladation step, thus generating in a cascade-like fashion an oligoene unit with sulphur at one terminus and the cyano group at the other. The intra- and intermolecular Pd-catalysed cyanosulfenylation of internal alkynes enables the formation of tetrasubstituted thioacrylonitriles and is extended to oligoyne systems leading to oligoenes and a cyanide transfer over four or six atoms.![]()
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Werz DB, Biju AT. Über bislang nicht beachtete Parallelen in der Reaktivität von Arinen und Donor‐Akzeptor‐Cyclopropanen. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201909213] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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69
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Sibold J, Kettelhoit K, Vuong L, Liu F, Werz DB, Steinem C. Synthesis of Gb
3
Glycosphingolipids with Labeled Head Groups: Distribution in Phase‐Separated Giant Unilamellar Vesicles. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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70
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Schitter T, Stammwitz S, Jones PG, Werz DB. An anti-Carbopalladation/Amination Cascade with Alkynes: Access to Tetrasubstituted Enamines and Pyrroles. Org Lett 2019; 21:9415-9419. [DOI: 10.1021/acs.orglett.9b03625] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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71
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Augustin AU, Merz JL, Jones PG, Mlostoń G, Werz DB. (4 + 3)-Cycloaddition of Donor–Acceptor Cyclopropanes with Thiochalcones: A Diastereoselective Access to Tetrahydrothiepines. Org Lett 2019; 21:9405-9409. [DOI: 10.1021/acs.orglett.9b03623] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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72
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Sibold J, Kettelhoit K, Vuong L, Liu F, Werz DB, Steinem C. Synthesis of Gb 3 Glycosphingolipids with Labeled Head Groups: Distribution in Phase-Separated Giant Unilamellar Vesicles. Angew Chem Int Ed Engl 2019; 58:17805-17813. [PMID: 31529754 PMCID: PMC6899692 DOI: 10.1002/anie.201910148] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/09/2019] [Indexed: 11/22/2022]
Abstract
The receptor lipid Gb3 is responsible for the specific internalization of Shiga toxin (STx) into cells. The head group of Gb3 defines the specificity of STx binding, and the backbone with different fatty acids is expected to influence its localization within membranes impacting membrane organization and protein internalization. To investigate this influence, a set of Gb3 glycosphingolipids labeled with a BODIPY fluorophore attached to the head group was synthesized. C24 fatty acids, saturated, unsaturated, α‐hydroxylated derivatives, and a combination thereof, were attached to the sphingosine backbone. The synthetic Gb3 glycosphingolipids were reconstituted into coexisting liquid‐ordered (lo)/liquid‐disordered (ld) giant unilamellar vesicles (GUVs), and STx binding was verified by fluorescence microscopy. Gb3 with the C24:0 fatty acid partitioned mostly in the lo phase, while the unsaturated C24:1 fatty acid distributes more into the ld phase. The α‐hydroxylation does not influence its partitioning.
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Köllmann C, Wiechert SM, Jones PG, Pietschmann T, Werz DB. Synthesis of 4′/5′-Spirocyclopropanated Uridine and d-Xylouridine Derivatives and Their Activity against the Human Respiratory Syncytial Virus. Org Lett 2019; 21:6966-6971. [DOI: 10.1021/acs.orglett.9b02555] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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74
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Augustin AU, Jones PG, Werz DB. Ring-Opening 1,3-Aminochalcogenation of Donor-Acceptor Cyclopropanes: A Three-Component Approach. Chemistry 2019; 25:11620-11624. [PMID: 31282001 PMCID: PMC6771889 DOI: 10.1002/chem.201902160] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/28/2019] [Indexed: 12/21/2022]
Abstract
A 1,3‐aminothiolation was realized by reacting 2‐substituted cyclopropane 1,1‐dicarboxylates with sulfonamides and N‐(arylthio)succinimides. Under Sn(OTf)2 catalysis the transformation proceeded smoothly to the corresponding ring‐opened products bearing the sulfonamide in the 1‐position next to the donor and the arylthio residue in the 3‐position next to the acceptor. The procedure was extended to the corresponding selenium analogues by employing N‐(phenylseleno)succinimides as an electrophilic selenium source.
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Kreft A, Ehlers S, Jones PG, Werz DB. Ring-Opening Reactions of Donor-Acceptor Cyclobutanes with Electron-Rich Arenes, Thiols, and Selenols. Org Lett 2019; 21:6315-6319. [PMID: 31380647 DOI: 10.1021/acs.orglett.9b02197] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Donor-acceptor (D-A) cyclobutanes with two geminal ester groups as acceptors are reacted with electron-rich arenes as nucleophiles to afford ring-opened products. AlCl3 mediates this Friedel-Crafts-type reaction. A variety of donors and electron-rich arenes are used. Nucleophilic thiols and selenols also trigger this ring-opening reaction. Furthermore, a comparison of various physical parameters has been carried out for several D-A cyclobutanes.
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