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using isolated 3. To our satisfaction, identical conversions were
obtained!
DOI: 10.1039/C9DT00529C
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Herein, we demonstrate that MeMn(CO) is an excellent
Mn(I) precursor to active Mn(I) catalysts with bifunctional
ligands. This finding addresses one of the shortcomings in this
field, namely that the synthons were limited to Mn(CO)
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Br and
Mn
2
(CO)10. Moreover, the use of MeMn(CO)
5
provides an ease
-
of the 16-e catalyst preparation that might otherwise be
impossible for certain metal-ligand or substrate combinations
and will be advantageous in ligand screening, the latter of which
we demonstrated in screening POP ligands for the Tishchenko
-
reaction. Related, many of the known 16-e Mn catalysts (e.g., 2
5
6
7
.
.
.
A. Mukherjee, A. Nerush, G. Leitus, L. J. W. Shimon, Y. Ben-
David, N. A. E. Jalapa, D. Milstein D. J. Am. Chem.
Soc., 2016, 138, 4298-4301.
S. Elangovan, C. Topf, S. Fischer, H. Jiao, A. Spannenberg, W.
Baumann, R. Ludwig, K. Junge, M. Beller, J. Am. Chem. Soc.
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and 3) are air sensitive. MeMn(CO) is air stable. Although
phosphine ligands are often air sensitive, they are usually stable
enough to short exposure to air. Thus, our new method greatly
simplifies the application and ligand screening potential of Mn
in organic synthesis. We liken this method to wide-spread use
2
016, 138, 8809-8814.
of adding Pd(OAc)
without the need to synthesize the active Pd catalyst. Hence the
use of MeMn(CO) is expected to find widespread application in
2
and phosphine ligand with substrate –
(a) P. J. Chirik, Acc. Chem. Res. 2015, 48, 1687-1695. (b) T. Zell,
R. Langer, ChemCatChem. 2018, 10, 1930-1940. (c) G. A.
Filonenko, R. V. Putten E. J. M. Hensen, E. A. Pidko, Chem. Soc.
Rev. 2018, 47, 1459-1483. (d) N. Gorgas, K. Kirchner. Acc.
Chem. Res. 2018, 51, 1558-1569. (e) T. Leischner, A.
Spannenberg, K. Junge, M. Beller, Organometallics 2018 DOI:
5
both the areas of organometallic chemistry where the
-
chemistry of the 16-e catalyst is sought, but also the organic
synthesis field wherein rapid catalyst generation in situ is highly
desirable.
1
0.1021/acs.organomet.8b00410.
8
.
.
Manganese focused reviews: (a) A. Mukherjee, D. Milstein, ACS
Catal. 2018, 8, 11435-11469. (b) B. Maji, M. K. Barman,
Synthesis 2017, 49, 3377-3393. (c) M. Garbe, K. Junge, M.
Beller, Eur. J. Org. Chem. 2017, 4344-4362. (d) F. Kallmeier, R.
Kempe, Angew. Chem. Int. Ed. 2018, 57, 46-60.
Acknowledgment
Financial support was provided by an ACS Petroleum Research
Fund (ACS-PRF-57861-DN13). We additionally thank Dr.
MacMillan (Cornell University XRD facility) for assistance with
providing the connectivity structure of the acyl complex.
9
1
T. Zell, R. Langer. ChemCatChem. 2018, 10, 1930-1940.
0. R. Closson, J. Kozikowski, T. Coffield, J. Org. Chem. 1957, 22,
98.
1. Occasionally cationic or neutral, six-coordinate tricarbonyl
molecules result with outer sphere bromide counterions; these
are even more tedious to activate with successive freeze-pump-
5
Conflicts of interest
There are no conflicts to declare.
1
–
thaw cycles that often do not yield 16-e species. See ref 5.
Notes and references
1
1
1
1
2. K. J. Kadassery, S. N. Macmillan, D. C. Lacy, Dalton.
Trans. 2018, 47, 12652-12655.
3. T. E. Gismondi, M. D. Rausch, J. Organomet. Chem. 1985, 284
(1), 59-71.
4. TOC graphic includes picture of crystals obtained in a 20 mL
scintillation vial.
5. We are not the first to see C–H bond activation with
MeMn(CO)
5
. For representative examples see: (a) T. Komuro, S.
Okawara, K. Furuyama, H. Tobita, Chem. Let. 2012, 41, 774-
7
76. (b) A. Fernández, J. M. Vila, J. Organomet. Chem. 2005,
6
90, 3638-3640. (c) J. M. Ressner, P. C. Wernett, C. S.
Kraihanzel, A. L. Rheingold, Organometallics 1988, 7, 1661-
663.
6. (a) Milstein obtained 92% using the dicarbonyl 2, which was
1
1.
2.
3.
4.
J. Zhang, G. Leitus, Y. Ben-David, D. Milstein, Angew. Chem.
Int. Ed. 2006, 45, 1113-1115.
J. R. Khusnutdinova, D. Mistein, Angew. Chem. Int. Ed. 2015,
1
1
isolated in 60% yield via ten 5-minute reflux/pumping cycles of
1
2
CO (generated from [(PNP )Mn(CO)
3
]Br and base) in THF. (b)
is refluxed under
5
4, 12236-12273.
C. Gunanathan, D. Milstein, Chem. Rev. 2014, 114, 12024-
2087.
If 2CO generated in situ from MeMn(CO)
5
argon, instead of heated in a sealed glass pressure bomb, there is
no conversion of the substrates.
1
H. A. Younus, W. Su, N. Ahmad, S. Chen, F. Verpoort, Adv.
Synth. Catal. 2015, 357, 283-330.
7. A. M. Tondreau, J. M. Boncella. Organometallics 2016, 35,
2
049-2052.
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