Ligand Exchange on and Allylic C–H Activation by Iron(0) Fragments: π-Complexes, Allyliron Species, and Metallacycles
| Autor: | Alicia Casitas, Eckhard Bill, Alois Fürstner, Helga Krause, Sigrid Lutz, Richard Goddard |
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| Rok vydání: | 2017 |
| Předmět: |
Allylic rearrangement
010405 organic chemistry Ligand Stereochemistry Chemistry Hydride Organic Chemistry Cyclopropene Metallacycle 010402 general chemistry 01 natural sciences Cycloaddition 0104 chemical sciences Catalysis Inorganic Chemistry chemistry.chemical_compound Cycloisomerization Physical and Theoretical Chemistry |
| Zdroj: | Organometallics. 37:729-739 |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/acs.organomet.7b00571 |
| Popis: | The complexes [(dippp)Fe(C2H4)2] (2) and [CpFe(C2H4)2][Li·(tmeda)] (5) both contain a formally zerovalent iron center but exhibit markedly different catalytic properties. Whereas 5 is able to induce a broad range of cycloisomerization and cycloaddition reactions, 2 is so far basically limited to cyclotrimerizations of alkynes and nitriles. Investigations into the behaviors of both complex vis-a-vis unsaturated substrates provided insights into the likely origins of this distinct behavior. Thus, ordinary terminal or internal alkenes were found not to replace the ligated ethylene units in 2, whereas the stronger π-acceptor ligands 1,5-cyclooctadiene, 2-norbornene, and tolane afforded the corresponding π-complexes 8, 9, 10, and 13. A cyclopropene derivative engaged in oxidative cyclization with formation of the corresponding metallacycle 12. Allyl-9-BBN or alkenyl-9-BBN derivatives succumbed to allylic C–H activation with formation of the unorthodox allyliron complexes 25 and 27 featuring a bridging hydride ... |
| Databáze: | OpenAIRE |
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