{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,4]],"date-time":"2026-04-04T10:24:50Z","timestamp":1775298290525,"version":"3.50.1"},"reference-count":53,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2022,9,2]],"date-time":"2022-09-02T00:00:00Z","timestamp":1662076800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006769","name":"Russian Science Foundation","doi-asserted-by":"publisher","award":["20-13-00044"],"award-info":[{"award-number":["20-13-00044"]}],"id":[{"id":"10.13039\/501100006769","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>A method for the [2+3] pyrroline annulation to the six-membered non-aromatic enols using 3-aryl-2H-azirines as annulation agents is developed in the current study. The reaction proceeds as a formal (3+2) cycloaddition via the N1-C2 azirine bond cleavage and is catalyzed by both Cu(II) and Cu(I) compounds. The new annulation method can be applied to prepare pyrrolo[3,2-c]quinoline, chromeno[3,4-b]pyrrole, and naphtho[1,8-ef]indole derivatives in good to excellent yields from enols of the quinolin-2-one, 2H-chromen-2-one, and 1H-phenalen-1-one series.<\/jats:p>","DOI":"10.3390\/molecules27175681","type":"journal-article","created":{"date-parts":[[2022,9,7]],"date-time":"2022-09-07T01:51:57Z","timestamp":1662515517000},"page":"5681","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Copper(II)-Catalyzed (3+2) Cycloaddition of 2H-Azirines to Six-Membered Cyclic Enols as a Route to Pyrrolo[3,2-c]quinolone, Chromeno[3,4-b]pyrrole, and Naphtho[1,8-ef]indole Scaffolds"],"prefix":"10.3390","volume":"27","author":[{"given":"Pavel A.","family":"Sakharov","sequence":"first","affiliation":[{"name":"Institute of Chemistry, St. Petersburg State University, 7\/9 Universitetskaya Nab., 199034 St. Petersburg, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8925-794X","authenticated-orcid":false,"given":"Nikolai V.","family":"Rostovskii","sequence":"additional","affiliation":[{"name":"Institute of Chemistry, St. Petersburg State University, 7\/9 Universitetskaya Nab., 199034 St. Petersburg, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6100-0309","authenticated-orcid":false,"given":"Alexander F.","family":"Khlebnikov","sequence":"additional","affiliation":[{"name":"Institute of Chemistry, St. Petersburg State University, 7\/9 Universitetskaya Nab., 199034 St. Petersburg, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5106-4723","authenticated-orcid":false,"given":"Mikhail S.","family":"Novikov","sequence":"additional","affiliation":[{"name":"Institute of Chemistry, St. Petersburg State University, 7\/9 Universitetskaya Nab., 199034 St. Petersburg, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2555","DOI":"10.1016\/j.tet.2019.03.040","article-title":"Advances in 2H-azirine chemistry: A seven-year update","volume":"75","author":"Khlebnikov","year":"2019","journal-title":"Tetrahedron"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"8153","DOI":"10.1021\/cr500036t","article-title":"The Chemistry of Transition Metals with Three-Membered Ring Heterocycles","volume":"114","author":"Huang","year":"2014","journal-title":"Chem. Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"4479","DOI":"10.1039\/C6OB00588H","article-title":"A novel strategy for the synthesis of thermally stable and apoptosis-inducing 2,3-dihydroazetes","volume":"14","author":"Smetanin","year":"2016","journal-title":"Org. Biomol. Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"4661","DOI":"10.1021\/acs.joc.1c00082","article-title":"Redox-Neutral 1,3-Dipolar Cycloaddition of 2H-Azirines with 2,4,6-Triarylpyrylium Salts under Visible Light Irradiation","volume":"86","author":"Pokhriyal","year":"2021","journal-title":"J. Org. Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1287","DOI":"10.1021\/acs.orglett.7b04007","article-title":"Iron-Catalyzed Radical Cycloaddition of 2H-Azirines and Enamides for the Synthesis of Pyrroles","volume":"20","author":"Zhao","year":"2018","journal-title":"Org. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"152319","DOI":"10.1016\/j.tetlet.2020.152319","article-title":"Nickel-catalyzed formal [3+2]-cycloaddition of 2H-azirines with 1,3-dicarbonyl compounds for the synthesis of pyrroles","volume":"61","author":"Zhao","year":"2020","journal-title":"Tetrahedron Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"4070","DOI":"10.1021\/acs.orglett.5b01994","article-title":"[3+2] Cycloaddition\/Oxidative Aromatization Sequence via Photoredox Catalysis: One-Pot Synthesis of Oxazoles from 2H-Azirines and Aldehydes","volume":"17","author":"Zeng","year":"2015","journal-title":"Org. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"3370","DOI":"10.1021\/acs.orglett.7b01305","article-title":"Base-Mediated Cascade Substitution\u2013Cyclization of 2H-Azirines: Access to Highly Substituted Oxazoles","volume":"19","author":"Duan","year":"2017","journal-title":"Org. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"6313","DOI":"10.1021\/acs.joc.7b00904","article-title":"Base-Induced Transformation of 2-Acyl-3-alkyl-2H-azirines to Oxazoles: Involvement of Deprotonation-Initiated Pathways","volume":"82","author":"Ning","year":"2017","journal-title":"J. Org. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3006","DOI":"10.1039\/D2QO00341D","article-title":"Switchable assembly of substituted pyrimidines and 2H-imidazoles via Cu(I)-catalysed ring expansion of 2-methoxyl-2H-azirines","volume":"9","author":"Sun","year":"2022","journal-title":"Org. Chem. Front."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3587","DOI":"10.1021\/acs.joc.9b03288","article-title":"Acid-Catalyzed 1,3-Dipolar Cycloaddition of 2H-Azirines with Nitrones: An Unexpected Access to 1,2,4,5-Tetrasubstituted Imidazoles","volume":"85","author":"Angyal","year":"2020","journal-title":"J. Org. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"4171","DOI":"10.1002\/ejoc.201800687","article-title":"Multicomponent Synthesis of Structurally Diverse Imidazoles Featuring Azirines, Amines and Aldehydes","volume":"2018","author":"Rossa","year":"2018","journal-title":"Eur. J. Org. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"10872","DOI":"10.1021\/acs.joc.0c01433","article-title":"General Synthesis of Tri-Carbo-Substituted N2-Aryl-1,2,3-triazoles via Cu-Catalyzed Annulation of Azirines with Aryldiazonium Salts","volume":"85","author":"Feng","year":"2020","journal-title":"J. Org. Chem."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3241","DOI":"10.1021\/acs.orglett.8b01090","article-title":"Copper-Catalyzed Ring-Expansion Cascade of Azirines with Alkynes: Synthesis of Multisubstituted Pyridines at Room Temperature","volume":"20","author":"Sujatha","year":"2018","journal-title":"Org. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"5384","DOI":"10.1021\/jo200788k","article-title":"An Aza Cyclopropylcarbinyl-Homoallyl Radical Rearrangement\u2013Radical Cyclization Cascade. Synthesis of Dibenzoimidazoazepine and Oxazepine Derivatives","volume":"76","author":"Khlebnikov","year":"2011","journal-title":"J. Org. Chem."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2249","DOI":"10.1021\/acs.joc.6b02932","article-title":"Visible-Light Driven Photocascade Catalysis: Union of N,N-Dimethylanilines and \u03b1-Azidochalcones in Flow Microreactors","volume":"82","author":"Borra","year":"2017","journal-title":"J. Org. Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4273","DOI":"10.1021\/acs.joc.9b00242","article-title":"1,3-Dipolar Cycloaddition of Isatin-Derived Azomethine Ylides with 2H-Azirines: Stereoselective Synthesis of 1,3-Diazaspiro[bicyclo[3.1.0]hexane]oxindoles","volume":"84","author":"Angyal","year":"2019","journal-title":"J. Org. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"5983","DOI":"10.1016\/S0040-4020(02)00611-7","article-title":"Diastereoselective Lewis acid-catalysed [4+2] cycloadditions of 3-alkyl-, 3-aryl- and 3-carboxyl-2H-azirines: A route to aziridine containing azabicyclo[4.1.0]heptanes and azatricyclo[2.2.1.0]nonanes","volume":"58","author":"Colin","year":"2002","journal-title":"Tetrahedron"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3263","DOI":"10.1055\/s-0029-1216945","article-title":"Ethyl 2-(diisopropoxyphosphoryl)-2H-azirine-3-carboxylate: Reactions with nucleophilic 1,3-dienes","volume":"2009","author":"Alves","year":"2009","journal-title":"Synthesis"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"6514","DOI":"10.1021\/acs.orglett.7b03211","article-title":"Rh-Catalyzed Conversion of 3-Diazoindolin-2-imines to 5H-Pyrazino[2,3-b]indoles with Photoluminescent Properties","volume":"19","author":"Ding","year":"2017","journal-title":"Org. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2349","DOI":"10.1021\/acs.joc.8b00115","article-title":"Regioselective Synthesis of Indolopyrazines through a Sequential Rhodium-Catalyzed Formal [3+3] Cycloaddition and Aromatization Reaction of Diazoindolinimines with Azirines","volume":"83","author":"Baek","year":"2018","journal-title":"J. Org. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1039\/C7OB02637D","article-title":"A novel approach to 5H-pyrazino[2,3-b]indoles via annulation of 3-diazoindolin-2-imines with 2H-azirines or 5-alkoxyisoxazoles under Rh(II) catalysis","volume":"16","author":"Ruvinskaya","year":"2018","journal-title":"Org. Biomol. Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1663","DOI":"10.1016\/j.tetlet.2003.12.105","article-title":"Formal [6+3] cycloaddition of fulvenes with 2H-azirine: A facile approach to the [2]pyrindines system","volume":"45","author":"Gupta","year":"2004","journal-title":"Tetrahedron Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"719","DOI":"10.1002\/cjoc.202100728","article-title":"Visible-Light-Promoted [3\u2009+\u20092] Cycloaddition of 2H-Azirines with Quinones: Access to Substituted Benzo[f]isoindole-4,9-diones","volume":"40","author":"Wang","year":"2022","journal-title":"Chin. J. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1745","DOI":"10.3762\/bjoc.9.201","article-title":"[3+2]-Cycloadditions of nitrile ylides after photoactivation of vinyl azides under flow conditions","volume":"9","author":"Kupracz","year":"2013","journal-title":"Beilstein J. Org. Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"3686","DOI":"10.1039\/D0QO00951B","article-title":"The Fe(III)-catalyzed decarboxylative cycloaddition of \u03b2-ketoacids and 2H-azirines for the synthesis of pyrrole derivatives","volume":"7","author":"Hu","year":"2020","journal-title":"Org. Chem. Front."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4148","DOI":"10.1021\/acs.orglett.5b01883","article-title":"Cu(I)\u2013NHC-Catalyzed (2+3)-Annulation of Tetramic Acids with 2H-Azirines: Stereoselective Synthesis of Functionalized Hexahydropyrrolo[3,4-b]pyrroles","volume":"17","author":"Rostovskii","year":"2015","journal-title":"Org. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"4663","DOI":"10.1016\/j.tet.2017.06.037","article-title":"Annulation of five-membered cyclic enols with 3-aryl-2H-azirines: Catalytic versus non-catalytic cycloaddition","volume":"73","author":"Sakharov","year":"2017","journal-title":"Tetrahedron"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3615","DOI":"10.1021\/acs.orglett.9b01043","article-title":"2H-Azirines as C\u2013C Annulation Reagents in Cu-Catalyzed Synthesis of Furo[3,2-c]quinolone Derivatives","volume":"21","author":"Sakharov","year":"2019","journal-title":"Org. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1042","DOI":"10.1021\/acs.joc.8b02459","article-title":"Access to 2,3-Fused Pyrroles via Visible Light Driven Coupling of \u03b1-Azidochalcones with 1\/2-Naphthols, or 2-Hydroxy-1,4-Naphthoquinone","volume":"84","author":"Borra","year":"2019","journal-title":"J. Org. Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"132115","DOI":"10.1016\/j.tet.2021.132115","article-title":"Organocatalytic asymmetric synthesis of pyrrolo[3,2-c]quinolines via a formal [3+2] cycloaddition-lactamization cascade reaction using a bifunctional squaramide catalyst","volume":"87","author":"Mahto","year":"2021","journal-title":"Tetrahedron"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1395","DOI":"10.1021\/ol0057030","article-title":"Enantioselective Synthesis of the Pyrroloquinoline Core of the Martinellines","volume":"2","author":"Nieman","year":"2000","journal-title":"Org. Lett."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"5250","DOI":"10.1021\/ol402469v","article-title":"Reaction of Cyclic \u03b1-Oxoketene Dithioacetals with Methylene Isocyanides: A Novel Pyrrole Annulation\u2013Ring-Expansion Domino Process","volume":"15","author":"Yugandar","year":"2013","journal-title":"Org. Lett."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"5346","DOI":"10.1021\/jo2006939","article-title":"Copper-Catalyzed Tandem Reaction of Isocyanides with N-(2-Haloaryl)propiolamides for the Synthesis of Pyrrolo[3,2-c]quinolin-4-ones","volume":"76","author":"Zhou","year":"2011","journal-title":"J. Org. Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2189","DOI":"10.1021\/ol016043h","article-title":"First Total Synthesis of Martinellic Acid, a Naturally Occurring Bradykinin Receptor Antagonist","volume":"3","author":"Ma","year":"2001","journal-title":"Org. Lett."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"6682","DOI":"10.1021\/ja00130a005","article-title":"Martinelline and Martinellic Acid, Novel G-Protein Linked Receptor Antagonists from the Tropical Plant Martinella iquitosensis (Bignoniaceae)","volume":"117","author":"Witherup","year":"1995","journal-title":"J. Am. Chem. Soc."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"152","DOI":"10.1016\/S0014-827X(99)00009-9","article-title":"Pyrrolo[3,2-c]quinoline derivatives: A new class of kynurenine-3-hydroxylase inhibitors","volume":"54","author":"Heidempergher","year":"1999","journal-title":"Farmaco"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"5496","DOI":"10.1016\/j.bmc.2012.07.039","article-title":"Discovery of pyrrolo[3,2-c]quinoline-4-one derivatives as novel hedgehog signaling inhibitors","volume":"20","author":"Ohashi","year":"2012","journal-title":"Bioorg. Med. Chem."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"972","DOI":"10.1021\/acschemneuro.6b00090","article-title":"Novel 1H-Pyrrolo[3,2-c]quinoline Based 5-HT6 Receptor Antagonists with Potential Application for the Treatment of Cognitive Disorders Associated with Alzheimer\u2019s Disease","volume":"7","author":"Grychowska","year":"2016","journal-title":"ACS Chem. Neurosci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2142","DOI":"10.1248\/cpb.17.2142","article-title":"Synthesis of nitrogen-containing heterocyclic compounds through nitrilium salt. I. Reaction of nitriles with 2-(\u03b1-hydroxy-methyl, -ethyl, and isopropyl)cyclohexanol in the presence of acid","volume":"17","author":"Ohki","year":"1969","journal-title":"Chem. Pharm. Bull."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Maini, P.N., and Sammes, M.P. (1988). The synthesis and chemistry of azolenines. Part 8. The Paal-Knorr reaction with cyclic 2-(acylmethyl)-2-alkyl-l,3-diketones: Isolation of 1-acyl-1H-pyrroles. J. Chem. Soc. Perkin Trans. 1, 161\u2013168.","DOI":"10.1039\/p19880000161"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1080\/00397918508076819","article-title":"An Efficient Synthesis of Arboricine","volume":"15","author":"Coppola","year":"1985","journal-title":"Synth. Commun."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2488","DOI":"10.1016\/j.tetlet.2016.04.089","article-title":"Palladium-Catalyzed Double C\u2013H Functionalization of 2-Aryl-1,3-Dicarbonyl Compounds: A Facile Access to Alkenylated Benzopyrans","volume":"57","author":"Choppakatla","year":"2016","journal-title":"Tetrahedron Lett."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1021\/jo00967a033","article-title":"A Convenient Procedure for the Preparation of 2-Arylazirines","volume":"37","author":"Hortmann","year":"1972","journal-title":"J. Org. Chem."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"4507","DOI":"10.1039\/C5CC00268K","article-title":"Rh(II)-catalyzed cycloadditions of 1-tosyl 1,2,3-triazoles with 2H-azirines: Switchable reactivity of Rh-azavinylcarbene as [2C]- or aza-[3C]-synthon","volume":"51","author":"Wang","year":"2015","journal-title":"Chem. Commun."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1234","DOI":"10.1002\/cber.19630960510","article-title":"Umsetzungen Einiger Diazoalkane Mit Isatin, N-Methyl-Isatin, Cumarandion Und Thionaphthenchinon","volume":"96","author":"Eistert","year":"1963","journal-title":"Chem. Ber."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"314","DOI":"10.1002\/cber.19630960139","article-title":"Ringerweiterung von Acenaphthenchinon Mit Diazoalkanen Unter Abfangen Der Produkte Als Enolate Bzw","volume":"96","author":"Eistert","year":"1963","journal-title":"Zinkchelate. Chem. Ber."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"5454","DOI":"10.1016\/j.tet.2008.04.009","article-title":"A prominent C-acylation\u2013cyclisation synthetic sequence and X-ray structure elucidation of benzothiopyranone derivatives","volume":"64","author":"Kikionis","year":"2008","journal-title":"Tetrahedron"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"980","DOI":"10.1002\/cber.190003301172","article-title":"Ueber Die Einwirkung von Natriumalkylaten Auf Phtalylglycinester Und Dessen Homologe","volume":"33","author":"Gabriel","year":"1900","journal-title":"Ber. Dtsch. Chem. Ges."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1107\/S0021889808042726","article-title":"OLEX2: A complete structure solution, refinement and analysis program","volume":"42","author":"Dolomanov","year":"2009","journal-title":"J. Appl. Cryst."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1107\/S0108767307043930","article-title":"A short history of SHELX","volume":"A64","author":"Sheldrick","year":"2008","journal-title":"Acta Cryst."},{"key":"ref_52","first-page":"3","article-title":"Crystal Structure Refinement with SHELXL","volume":"C71","author":"Sheldrick","year":"2015","journal-title":"Acta Cryst."},{"key":"ref_53","first-page":"3","article-title":"SHELXT\u2014Integrated Space-Group and Crystal-Structure Determination","volume":"A71","author":"Sheldrick","year":"2015","journal-title":"Acta Cryst."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/27\/17\/5681\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:22:47Z","timestamp":1760142167000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/27\/17\/5681"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,9,2]]},"references-count":53,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2022,9]]}},"alternative-id":["molecules27175681"],"URL":"https:\/\/doi.org\/10.3390\/molecules27175681","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,9,2]]}}}