Protonation at the aromatic ring of samarium benzophenone dianion species. Isolation and structural characterization of a samarium(III) enolate complex

Journal Article · Wed Nov 30 04:00:00 EST 1994 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00103a047· OSTI ID:6730843

Hou, Z; Yoshimura, Takashi; Wakatsuki, Yasuo ^[1]

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1. RIKEN, Saitama (Japan)

The reduction of aromatic compounds into their dihydro derivatives by dissolving metal/alcohol systems (the Birch reduction) is a useful methodology in organic synthesis. Of particular importance is the reduction of aromatic carbonyl compounds such as aromatic acids, esters, amides, and monoaryl ketones, which usually generates in situ useful metal enolate intermediates that upon further reaction with electrophiles yield a variety of cyclohexadiene derivatives. One of the possible processes to generate these metal enolate intermediates is thought to be the monoprotonation of dianionic species at the para position of the aromatic rings. On the other hand, the reduction of diaryl ketones by alkali metals in liquid ammonia or by lanthanide metals in THF/HMPA or DME has been well known to afford the corresponding ketone dianions. The first X-ray structure of metal ketone dianion complexes, [Yb([mu]-[eta][sup 1],[eta][sup 2]-OCPh[sub 2]) (HMPA)[sub 2]][sub 2], has been recently determined in this laboratory. Protonation of this complex with ArOH or CpMo(CO)[sub 3]H also occurred at the carbonyl unit to release benzhydrol. In striking contrast to these results, when the analogous samarium benzophenone dianion species was aallowed to react with ArOH, the protonation occurred at the aromatic ring to give a samarium(III) enolate complex. 15 refs., 1 fig.

• OSTI ID: 6730843
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 116:24; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
ALCOHOLS
AROMATICS
CHEMICAL REACTIONS
COHERENT SCATTERING
COMPLEXES
DEUTERIUM COMPOUNDS
DIFFRACTION
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOMERIZATION
MAGNETIC RESONANCE
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
RARE EARTH COMPLEXES
RESONANCE
SAMARIUM COMPLEXES
SCATTERING
X-RAY DIFFRACTION
YTTERBIUM COMPLEXES