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Frontispiece: Boosting Molecular Complexity with O 2 : Iron‐Catalysed Oxygenation of 1‐Arylisochromans through Dehydrogenation, Csp 3 −O Bond Cleavage and Hydrogenolysis
Author(s) -
GonzalezdeCastro Angela,
Robertson Craig M.,
Xiao Jianliang
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201981765
Subject(s) - hydrogenolysis , chemistry , dehydrogenation , bond cleavage , catalysis , cleavage (geology) , peroxide , selectivity , medicinal chemistry , photochemistry , organic chemistry , materials science , fracture (geology) , composite material
1‐Arylisochromans were easily converted in valuable 2‐(hydroxyethyl)benzophenones by means of a selective Csp 3 −O aerobic cleavage promoted by a Fe II –pyridyl(bis‐imidazolidine) catalyst. The reaction proceeded with high selectivity and impressive functional group tolerance at mild and environmentally friendly conditions. From a mechanistic perspective, the iron catalyst promotes the dehydrogenative oxygenation of the 1‐arylisochroman releasing a structurally characterized peroxide intermediate and H 2 gas. The formation of the 2‐(hydroxyethyl)benzophenones is postulated to occur through Csp 3 −O bond cleavage of the peroxide at the iron center followed by the hydrogenolysis of the Fe−O bonds with the released H 2 . Interestingly, electron‐rich 1‐arylisochromans were also transformed in benzoates by means of a radical auto‐oxidative Csp 3 −Csp 2 cleavage, further highlighting the synthetic potential that can be gained by aerobic cleavages. For more information see the Full Paper by J. Xiao et al. on page 4345 ff.