cs5009656_si_001.pdf (2.55 MB)
Well-Defined Iron Catalysts for the Acceptorless Reversible Dehydrogenation-Hydrogenation of Alcohols and Ketones
journal contribution
posted on 2014-11-07, 00:00 authored by Sumit Chakraborty, Paraskevi O. Lagaditis, Moritz Förster, Elizabeth A. Bielinski, Nilay Hazari, Max C. Holthausen, William D. Jones, Sven SchneiderAcceptorless
dehydrogenation of alcohols, an important organic transformation,
was accomplished with well-defined and inexpensive iron-based catalysts
supported by a cooperating PNP pincer ligand. Benzylic and aliphatic
secondary alcohols were dehydrogenated to the corresponding ketones
in good isolated yields upon release of dihydrogen. Primary alcohols
were dehydrogenated to esters and lactones, respectively. Mixed primary/secondary
diols were oxidized at the secondary alcohol moiety with good chemoselectivity.
The mechanism of the reaction was investigated using both experiment
and DFT calculations, and the crucial role of metal–ligand
cooperativity in the reaction was elucidated. The iron complexes are
also excellent catalysts for the hydrogenation of challenging ketone
substrates at ambient temperature under mild H2 pressure,
the reverse of secondary alcohol dehydrogenation.