{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,29]],"date-time":"2026-10-29T17:29:29Z","timestamp":1793294969744,"version":"4.5.0"},"reference-count":98,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[2014,12,10]],"date-time":"2014-12-10T00:00:00Z","timestamp":1418169600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Angew Chem Int Ed"],"published-print":{"date-parts":[[2015,1,26]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>The alkylation of complexes <jats:bold>2<\/jats:bold> and <jats:bold>7<\/jats:bold> with Grignard reagents containing \u03b2\u2010hydrogen atoms is a process of considerable relevance for the understanding of C\u2013H activation as well as C\u2013C bond formation mediated by low\u2010valent iron species. Specifically, reaction of <jats:bold>2<\/jats:bold> with EtMgBr under an ethylene atmosphere affords the bis\u2010ethylene complex <jats:bold>1<\/jats:bold> which is an active precatalyst for prototype [2+2+2] cycloaddition reactions and a valuable probe for mechanistic studies. This aspect is illustrated by its conversion into the bis\u2010alkyne complex <jats:bold>6<\/jats:bold> as an unprecedented representation of a cycloaddition catalyst loaded with two substrates molecules. On the other hand, alkylation of <jats:bold>2<\/jats:bold> with 1\u2005equivalent of cyclohexylmagnesium bromide furnished the unique iron alkyl species <jats:bold>11<\/jats:bold> with a 14\u2010electron count, which has no less than four \u03b2\u2010H atoms but is nevertheless stable at low temperature against \u03b2\u2010hydride elimination. In contrast, the exhaustive alkylation of <jats:bold>1<\/jats:bold> with cyclohexylmagnesium bromide triggers two consecutive C\u2013H activation reactions mediated by a single iron center. The resulting complex has a diene dihydride character in solution (<jats:bold>15<\/jats:bold>), whereas its structure in the solid state is more consistent with an \u03b7<jats:sup>3<\/jats:sup>\u2010allyl iron hydride rendition featuring an additional agostic interaction (<jats:bold>14<\/jats:bold>). Finally, the preparation of the cyclopentadienyl iron complex <jats:bold>25<\/jats:bold> illustrates how an iron\u2010mediated C\u2013H activation cascade can be coaxed to induce a stereoselective C\uf8ffC bond formation. The structures of all relevant new iron complexes in the solid state are presented.<\/jats:p>","DOI":"10.1002\/anie.201410069","type":"journal-article","created":{"date-parts":[[2014,12,10]],"date-time":"2014-12-10T14:36:06Z","timestamp":1418222166000},"page":"1521-1526","source":"Crossref","is-referenced-by-count":79,"title":["Elementary Steps of Iron Catalysis: Exploring the Links between Iron Alkyl and Iron Olefin Complexes for their Relevance in C\uf8ffH Activation and C\uf8ffC Bond Formation"],"prefix":"10.1002","volume":"54","author":[{"given":"Alicia","family":"Casitas","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helga","family":"Krause","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard","family":"Goddard","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alois","family":"F\u00fcrstner","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2014,12,10]]},"reference":[{"key":"e_1_2_2_1_2","unstructured":"\u00a0"},{"key":"e_1_2_2_2_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.198701531"},{"key":"e_1_2_2_2_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19870990214"},{"key":"e_1_2_2_3_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.198608101"},{"key":"e_1_2_2_3_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19860980915"},{"key":"e_1_2_2_4_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-328X(86)80049-3"},{"key":"e_1_2_2_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-328X(87)85057-X"},{"key":"e_1_2_2_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-328X(87)85007-6"},{"key":"e_1_2_2_7_2","unstructured":"A.\u2005J. Frings Dissertation Ruhr\u2010Universit\u00e4t Bochum 1988."},{"key":"e_1_2_2_8_2","doi-asserted-by":"publisher","DOI":"10.1351\/pac199062061169"},{"key":"e_1_2_2_9_2","unstructured":"See also:"},{"key":"e_1_2_2_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-328X(91)83162-W"},{"key":"e_1_2_2_11_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-328X(97)00770-5"},{"key":"e_1_2_2_12_2","unstructured":"\u00a0"},{"key":"e_1_2_2_13_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201404677"},{"key":"e_1_2_2_13_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.201404677"},{"key":"e_1_2_2_14_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja410234x"},{"key":"e_1_2_2_15_2","unstructured":"Stoichiometric reactions showed such complexes to be nucleophilic at carbon cf. Ref.\u2005[1]."},{"key":"e_1_2_2_16_2","unstructured":"\u00a0"},{"key":"e_1_2_2_17_2","doi-asserted-by":"publisher","DOI":"10.1021\/om9610004"},{"key":"e_1_2_2_18_2","doi-asserted-by":"publisher","DOI":"10.1515\/znb-1995-0407"},{"key":"e_1_2_2_19_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-328X(94)88046-8"},{"key":"e_1_2_2_20_2","doi-asserted-by":"publisher","DOI":"10.1021\/om00004a048"},{"key":"e_1_2_2_21_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr100198w"},{"key":"e_1_2_2_22_2","unstructured":"\u00a0"},{"key":"e_1_2_2_23_2","volume-title":"Iron Catalysis in Organic Chemistry: Reactions and Applications","year":"2008"},{"key":"e_1_2_2_24_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo100693m"},{"key":"e_1_2_2_25_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja0777180"},{"key":"e_1_2_2_26_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja801466t"},{"key":"e_1_2_2_27_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.200502859"},{"key":"e_1_2_2_27_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.200502859"},{"key":"e_1_2_2_28_2","doi-asserted-by":"publisher","DOI":"10.1039\/b918818e"},{"key":"e_1_2_2_29_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar800039x"},{"key":"e_1_2_2_30_2","unstructured":"In addition to the structures of complexes6 11 14 and25shown in the text the structures of complexes1 2 and20in the solid state are depicted in the Supporting Information. CCDC\u20051026194\u2005(1) CCDC\u20051026195\u2005(6) CCDC\u20051026196\u2005(25) CCDC\u20051026197\u2005(20) CCDC\u20051026198\u2005(14) CCDC\u20051026199\u2005(11) CCDC\u20051026200\u2005(2) contain the supporting crystallographic data for this paper. These data can be obtained free of charge from the Cambridge Crystallographic Data Centre viawww.ccdc.cam.ac.uk\/data_request\/cif."},{"key":"e_1_2_2_31_2","unstructured":"The analogous complex18with a dippe ligand prepared from7and EtMgBr is less stable but well behaved when used immediately after formation see Scheme\u20054."},{"key":"e_1_2_2_32_2","doi-asserted-by":"publisher","DOI":"10.1021\/om971110q"},{"key":"e_1_2_2_33_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201404078"},{"key":"e_1_2_2_33_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.201404078"},{"key":"e_1_2_2_34_2","doi-asserted-by":"publisher","DOI":"10.1021\/ic052136"},{"key":"e_1_2_2_35_2","unstructured":"For iron\u2010catalyzed reactions of 1 3\u2010diene\u2010 or diene\u2010containing entities see the following and literature therein:"},{"key":"e_1_2_2_36_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4039(01)86189-X"},{"key":"e_1_2_2_37_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.198307781"},{"key":"e_1_2_2_37_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19830951014"},{"key":"e_1_2_2_38_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4020(01)87749-8"},{"key":"e_1_2_2_39_2","doi-asserted-by":"crossref","unstructured":"J.Raynaud J. Y.Wu T.Ritter Angew. Chem. Int. Ed.\u00ad2012 51 11805\u201311808;Angew. Chem.\u00ad2012 124 11975\u201311978;","DOI":"10.1002\/anie.201205152"},{"key":"e_1_2_2_40_2","doi-asserted-by":"crossref","unstructured":"C.\u2010L.Sun A.F\u00fcrstner Angew. Chem. Int. Ed.\u00ad2013 52 13071\u201313075;Angew. Chem.\u00ad2013 125 13309\u201313313.","DOI":"10.1002\/anie.201307028"},{"key":"e_1_2_2_41_2","unstructured":"\u00a0"},{"key":"e_1_2_2_42_2","doi-asserted-by":"publisher","DOI":"10.1007\/s11434-012-5141-z"},{"key":"e_1_2_2_43_2","doi-asserted-by":"publisher","DOI":"10.1002\/9783527623273.ch9"},{"key":"e_1_2_2_44_2","unstructured":"\u00a0"},{"key":"e_1_2_2_45_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201102001"},{"key":"e_1_2_2_45_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.201102001"},{"key":"e_1_2_2_46_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo400057t"},{"key":"e_1_2_2_47_2","unstructured":"For other defined iron precatalysts in [2+2+2] cycloadditions see Ref.\u2005[10] and the following:"},{"key":"e_1_2_2_48_2","doi-asserted-by":"publisher","DOI":"10.1039\/C3CC47700B"},{"key":"e_1_2_2_49_2","doi-asserted-by":"publisher","DOI":"10.1039\/B923663P"},{"key":"e_1_2_2_50_2","doi-asserted-by":"publisher","DOI":"10.1021\/om0201967"},{"key":"e_1_2_2_51_2","doi-asserted-by":"publisher","DOI":"10.1021\/om950800w"},{"key":"e_1_2_2_52_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-328X(00)00211-4"},{"key":"e_1_2_2_53_2","unstructured":"Reaction of tolane with the related olefin complex [Cp*Fe(C2H4)2] afforded a tetraphenyl butadienyl complex by reductive elimination of a putative ferrole intermediate cf. Ref.\u2005[10]."},{"key":"e_1_2_2_54_2","doi-asserted-by":"publisher","DOI":"10.3987\/REV-09-SR(S)6"},{"key":"e_1_2_2_55_2","unstructured":"For less\u2010canonical iron complexes isolated from (stoichiometric) cyclotrimerizations see:"},{"key":"e_1_2_2_56_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.198306201"},{"key":"e_1_2_2_56_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19830950816"},{"key":"e_1_2_2_57_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.199001261"},{"key":"e_1_2_2_57_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19901020206"},{"key":"e_1_2_2_58_2","unstructured":"A search in the Cambridge Crystallographic Data Base gave no hits for mononuclear Fe0bis(alkyne)complexes."},{"key":"e_1_2_2_59_2","unstructured":"As tolane is tightly bound 6is only a poor catalyst for the cyclotrimerization of 3\u2010hexyne."},{"key":"e_1_2_2_60_2","doi-asserted-by":"publisher","DOI":"10.1107\/S0567740877011674"},{"key":"e_1_2_2_61_2","doi-asserted-by":"publisher","DOI":"10.1021\/om00147a014"},{"key":"e_1_2_2_62_2","unstructured":"Such a mechanism has been invoked in the preparation of low\u2010valent iron catalysts for cross coupling see:"},{"key":"e_1_2_2_63_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja027190t"},{"key":"e_1_2_2_64_2","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3773(20020215)41:4<609::AID-ANIE609>3.0.CO;2-M"},{"key":"e_1_2_2_64_3","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3757(20020215)114:4<632::AID-ANGE632>3.0.CO;2-M"},{"key":"e_1_2_2_65_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo0498866"},{"key":"e_1_2_2_66_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo049885d"},{"key":"e_1_2_2_67_2","doi-asserted-by":"publisher","DOI":"10.1002\/adsc.201301089"},{"key":"e_1_2_2_68_2","unstructured":"We cannot firmly rule out a successive pathway in which an initial \u03b2\u2010hydride elimination from a tetrahedral 14\u2010electron complex of type [L2Fe(Et)Cl] precedes the replacement of the second chloride by an ethyl group; yet putative [L2Fe(Et)Cl] must fulfill the exact same conditions for \u03b2\u2010hydride elimination as the diethyl complex9."},{"key":"e_1_2_2_69_2","doi-asserted-by":"publisher","DOI":"10.1021\/om400325x"},{"key":"e_1_2_2_70_2","doi-asserted-by":"publisher","DOI":"10.1021\/om0103106"},{"key":"e_1_2_2_71_2","unstructured":"For metastable iron complexes with other ligand sets and coordination geometries which contain alkyl ligands with \u03b2\u2010H atoms see:"},{"key":"e_1_2_2_72_2","doi-asserted-by":"publisher","DOI":"10.1021\/om049415"},{"key":"e_1_2_2_73_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja803296f"},{"key":"e_1_2_2_74_2","unstructured":"For the concept see:"},{"key":"e_1_2_2_75_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar990028j"},{"key":"e_1_2_2_76_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0010-8545(02)00283-7"},{"key":"e_1_2_2_77_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00283a062"},{"key":"e_1_2_2_78_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0610747104"},{"key":"e_1_2_2_79_2","unstructured":"\u00a0"},{"key":"e_1_2_2_80_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00523a013"},{"key":"e_1_2_2_81_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00472a061"},{"key":"e_1_2_2_82_2","doi-asserted-by":"publisher","DOI":"10.1021\/ic50161a017"},{"key":"e_1_2_2_83_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.199310731"},{"key":"e_1_2_2_83_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19931050741"},{"key":"e_1_2_2_84_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00225a012"},{"key":"e_1_2_2_85_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol400056z"},{"key":"e_1_2_2_86_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201402719"},{"key":"e_1_2_2_86_3","doi-asserted-by":"publisher","DOI":"10.1002\/ange.201402719"}],"container-title":["Angewandte Chemie International Edition"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fanie.201410069","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/anie.201410069","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,16]],"date-time":"2023-10-16T13:24:58Z","timestamp":1697462698000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/anie.201410069"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2014,12,10]]},"references-count":98,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2015,1,26]]}},"alternative-id":["10.1002\/anie.201410069"],"URL":"https:\/\/doi.org\/10.1002\/anie.201410069","archive":["Portico"],"relation":{},"ISSN":["1433-7851","1521-3773"],"issn-type":[{"value":"1433-7851","type":"print"},{"value":"1521-3773","type":"electronic"}],"subject":[],"published":{"date-parts":[[2014,12,10]]}}}