Organometallics
Communication
design in Mn-based systems that are rapidly emerging in recent
years.
this work was supported by award S10RR029517 from the
National Center for Research Resources. Kevin Zemaitis is
acknowledged for the HRMS analysis of EMn(CO)3Br. Paul
M. Fanara is thanked for the synthesis of E.
An earlier report showed the potential of using methyl-
manganese pentacarbonyl (MeMn), foregoing the need to use
a base.18 A heated mixture of HLPh + MeMn in toluene forms
the same species (31P {1H} NMR 74 ppm; among other
species) as when HLPhMn(CO)3Br and 2 equiv of base are
reacted in toluene (Figure S6). When the HLPh + MeMn
toluene mixture with 31P{1H} NMR 74 ppm was added to a
solution of 1a in 2-propanol and heated, 1aH2 was isolated in
58% yield. Furthermore, a 2 mol % HLPh + MeMn mixture
prepared in the presence of 7b quantitatively isomerized the
substrate to 7a (Scheme 5).
In conclusion, we have demonstrated that β-amino
phosphine-supported Mn(I)-carbonyl complexes are excellent
catalysts for TH of ketones with good functional group
tolerance under mild conditions. Chalcones are selectively
reduced to the ketones in short time intervals, and this appears
to be a unique property of the catalysts derived from β-amino
phosphine ligands. Additionally, the isomerization of allylic
alcohols by the same catalysts was demonstrated and is related
to the selectivity of the chalcone reduction. Importantly, these
reactions highlight that Mn(I) is a versatile ion to perform
reactions where the ligand controls chemoselectivity. Given its
abundance and low toxicity in comparison to most other metal
ions, the area of Mn(I) in catalysis is expected to see growth in
unique substrate and chemoselective transformations.
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ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available online. The
Supporting Information is available free of charge on the
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Accession Codes
tallographic data for this paper. These data can be obtained
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
AUTHOR INFORMATION
Corresponding Author
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Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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Financial support was provided by the University at Buffalo
(UB) Research Foundation, the ACS Petroleum Research
Fund (ACS-PRF-57861-DN13), and the National Science
Foundation (1847933). This work used the UB Chemistry
Instrument Center facilities; the mass spectrometer used for
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