Mechanistic insights into the PdII-catalyzed chemoselective N-demethylation vs. cyclometalation reactivity pathways in 1-Aryl-N,N-dimethylethanamines
Two structurally isomeric substituted N,N-dimethylethanamines have been prepared. Treatment of the 2,4-di-tert-butylphenyl isomer with PdII ions generated the ortho-metalated complexes. On the other hand, treatment of the 2,5-di-tert-butylphenyl-substituted amine resulted in the unexpected chemosele...
| Hauptverfasser: | , , , , , , |
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| Format: | Journal Article |
| Sprache: | English |
| Veröffentlicht: |
2014
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| Schlagworte: | |
| Online Zugang: | https://hdl.handle.net/10356/105314 http://hdl.handle.net/10220/20485 http://dx.doi.org/10.1002/ejic.201402547 |
| Zusammenfassung: | Two structurally isomeric substituted N,N-dimethylethanamines have been prepared. Treatment of the 2,4-di-tert-butylphenyl isomer with PdII ions generated the ortho-metalated complexes. On the other hand, treatment of the 2,5-di-tert-butylphenyl-substituted amine resulted in the unexpected chemoselective cleavage of one of the three N–C bonds, thus generating the corresponding secondary amine. The N-demethylation process could be catalyzed at room temperature by palladium(II) catalysts such as PdCl2 or Pd(OAc)2. Furthermore, treatment with a stoichiometric amount of PdII ions gave a metal complex in which both secondary amines were bound to Pd in an N-monodentate fashion. When triethylamine was introduced, one of the N-ethyl groups in NEt3 was cleaved, and an unexpected heteroamine complex was produced. The products generated were isolated and characterized by X-ray crystallography. Mechanistic insights into the cyclometalation and C–N cleavage observed are discussed. |
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