Iron-Catalyzed [2π + 2π] Cycloaddition of α,ω-Dienes: The Importance of Redox-Active Supporting Ligands
2006; American Chemical Society; Volume: 128; Issue: 41 Linguagem: Inglês
10.1021/ja064711u
ISSN1943-2984
AutoresM.W. Bouwkamp, A.C. Bowman, Emil B. Lobkovsky, Paul J. Chirik,
Tópico(s)Catalytic C–H Functionalization Methods
ResumoThe bis(imino)pyridine iron bis(dinitrogen) complex, (iPrPDI)Fe(N2)2 (iPrPDI = 2,6-(2,6-iPr2C6H3NCR)2C5H3N), serves as an efficient precursor for the catalytic [2pi + 2pi] cycloaddition of alpha,omega-dienes to yield the corresponding bicycles. For amine substrates, the rate of catalytic turnover increases with the size of the nitrogen substituents, demonstrating competing heterocycle coordination and product inhibition. In one case, a bis(imino)pyridine iron azobicycloheptane product was characterized by X-ray diffraction. Preliminary mechanistic studies highlight the importance of the redox activity of the bis(imino)pyridine ligand to maintain the ferrous oxidation state throughout the catalytic cycle.
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