Rethinking Basic Concepts-Hydrogenation of Alkenes Catalyzed by Bench-Stable Alkyl Mn(I) Complexes

Article abstract of DOI:10.1021/acscatal.9b03963

An efficient additive-free manganese-catalyzed hydrogenation of alkenes to alkanes with molecular hydrogen is described. This reaction is atom economic, implementing an inexpensive, earth-abundant nonprecious metal catalyst. The most efficient precatalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)₃(CH₂CH₂CH₃)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid hydrogenolysis to form the active 16e Mn(I) hydride catalyst [Mn(dippe)(CO)₂(H)]. A range of mono- A nd disubstituted alkenes were efficiently converted into alkanes in good to excellent yields. The hydrogenation of 1-alkenes and 1,1-disubstituted alkenes proceeds at 25 °C, while 1,2-disubstituted alkenes require a reaction temperature of 60 °C. In all cases, a catalyst loading of 2 mol % and a hydrogen pressure of 50 bar were applied. A mechanism based on DFT calculations is presented, which is supported by preliminary experimental studies.

Full text of DOI:10.1021/acscatal.9b03963

Subscriber access provided by TRINITY COLL
Letter
Rethinking Basic Concepts – Hydrogenation of Alkenes
Catalyzed by Bench-Stable Alkyl Mn(I) Complexes
Stefan Weber, Berthold Stöger, Luis Filipe Veiros, and Karl Kirchner
ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.9b03963 • Publication Date (Web): 23 Sep 2019
Downloaded from pubs.acs.org on September 24, 2019
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 8
ACS Catalysis
1
2
3
4
5
6
7
8
9
Rethinking Basic Concepts – Hydrogenation of Alkenes
Catalyzed by Bench-Stable Alkyl Mn(I) Complexes
Stefan Weber,† Berthold Stöger,‡ Luis F. Veiros,§ and Karl Kirchner*, †
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
†Institute of Applied Synthetic Chemistry and ‡X-ray Center, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna,
AUSTRIA
§Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais No. 1, 1049-001 Lisboa,
PORTUGAL
ABSTRACT: An efficient additive-free manganese-catalyzed hydrogenation of alkenes to alkanes with molecular hydrogen is
described. This reaction is atom economic, implementing
an inexpensive, earth abundant non-precious metal
catalyst. The most efficient pre-catalyst is the bench-
stable alkyl bisphosphine Mn(I) complex fac-
[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is
initiated by migratory insertion of a CO ligand into the
Mn-alkyl bond to yield an acyl intermediate which
undergoes rapid hydrogenolysis to form the active 16e
Mn(I) hydride catalyst [Mn(dippe)(CO)2(H)]. A range of
mono- and disubstituted alkenes were efficiently
converted into alkanes in good to excellent yields. The
hydrogenation of 1-alkenes and 1,1-disubstituted alkenes proceeds at 25 oC, while 1,2-disubstituted alkenes require a reaction
temperature of 60oC. In all cases, a catalyst loading of 2 mol % and a hydrogen pressure of 50 bar was applied. A mechanism
based on DFT calculations is presented which is supported by preliminary experimental studies.
KEYWORDS: Hydrogenation, alkenes, manganese, bisphosphine complexes, alkyl complexes, DFT calculations
One of the fundamental research goals in modern
chemistry is the development of sustainable, efficient and
selective syntheses. Accordingly, it is quite important to
perform reactions under catalytic conditions and to replace
precious metal catalysts by Earth abundant non-precious
metal catalysts.1 In particular base metals such as iron and
manganese are promising candidates as these belong to the
most abundant metals in the Earth crust, are inexpensive,
and exhibit a low environmental impact. In this context,
atom-efficient and clean processes which permit access to a
green synthesis of valuable products such as alkanes,
alcohols and amines is the hydrogenation of olefins,
alkynes, carbonyl compounds, imines and nitriles with
molecular hydrogen are
investigation over the past decade,4-13 low valent Mn(I)
catalysts just appeared in 2016 as new but very powerful
players in this field.8-11,15 The latter are typically
substitutionally inert 18e- complexes bearing two or three
CO ligands and bi- and tridentate N, C, S, and P-donor
ligands, respectively (Scheme 1) where substrate binding
occurs in an outer-sphere fashion. Thus, these types of
complexes are active only for the hydrogenation of polar
multiple bonds such as nitriles, imines, and carbonyl
compounds, while alkenes are not hydrogenated. In fact,
examples of manganese catalysts which are capable of
hydrogenating unactivated C=C double bonds are
exceedingly rare.16
We describe here the synthesis and catalytic activity of
new well-defined and bench-stable alkyl carbonyl Mn(I)
complexes of the type fac-[Mn(dpre)(CO)3(R)] (dpre = 1,2-
Scheme 1. Structural Motifs of Most Mn(I)
(De)hydrogenation Catalysts (X = Cl, Br, H)
bis(di-n-propylphosphino) ethane,
CH2CH2CH3) and fac-[Mn(dippe)(CO)3(CH2CH2CH3) (dippe =
1,2-bis(di-iso-propylphosphino)ethane) for the
hydrogenation of alkenes with molecular hydrogen.
R
=
CH3, CH2CH3,
X
X
L1
CO
L2
L3
Mn
CO
L1
L2
Mn
CO
CO
CO
Scheme 2. Formation of a Coordinatively Unsaturated
Mn(I) Hydride Species via Alkyl Migration and
Hydrogenolysis of an Acyl Intermediate
of paramount importance.2,3 While iron, cobalt, and nickel
hydrogenation catalysts had been subject of intense
ACS Paragon Plus Environment

ACS Catalysis
Page 2 of 8
H
H
R
for the hydrogenation of 1-dodecene (11) as model
R
R
1
2
3
4
5
6
7
8
substrate (Scheme 4). Selected optimization experiments are
depicted in Table 1. With complexes 3-6 as pre-catalysts
and a catalyst loading of 2 mol% at 100oC and a hydrogen
pressure of 50 bar H2 in toluene for 18 h, dodecane was
obtained in essentially quantitative yield (Table 1, entries 1-
4). Under the same reaction conditions complexes 7-10
were catalytically inactive and no reaction took place even
when the catalyst loading was increased to 4 mol% (Table 1,
entries 5-8). This clearly emphasizes that strongly electron
donating co-ligands such as aliphatic bisphosphines are
required to achieve high catalytic activity. Moreover, the
coordinatively saturated and inert hydride complexes 7 and
10 are inactive due to the lack of a vacant coordination site
and are not intermediates in the catalytic process. Likewise,
if the catalytic reaction is performed in the presence of
PMe3 no hydrogenation reaction took place indicating that
PMe3 coordinates to the Mn(I) center also blocking the
H
H
[Mn]
H
[Mn]
C
[Mn]
CO
C
[Mn]
CO
O
O
catalytically active
species
R
R2
P
Mn
C
H
[Mn] =
O
P
CO
R2
We take advantage of the fact that (i) CO ligands of Mn(I)
alkyl carbonyl complexes are known to undergo migratory
insertions to form acyl complexes if strong field ligands such
as CO or tertiary phosphines are present - a well-known
textbook reaction.17 and (ii) that hydrogenolysis of a
transition-metal acyl complexes affords aldehydes and
metal hydride complexes - typically the final step in both
stoichiometric and catalytic hydroformylations of alkenes.18
Accordingly, the catalytic process is initiated by migratory
insertion of a CO ligand into the Mn-alkyl bond to yield acyl
intermediates which undergo rapid hydrogenolysis to create
the active 16e- Mn(I) hydride catalysts (Scheme 2).
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
o
vacant site for incoming substrates. At 40 C and a catalyst
loading of 2 mol% in diethyl ether as solvent complex 3 was
no longer catalytically active, while complexes 4-6 were still
efficient to convert 1-dodecene to dodecane in quantitative
yield (Table 1, entries 9-12). It has to be noted that the rate
of alkyl migration follows the order nPr > Et > Me as
established by Moss and co-workers some years ago.23
Finally, at 25 oC complexes 3-5 were no longer active,
whereas with complex 6 dodecane was isolated in 99% yield
(Table 1, entries 13-15) suggesting that sterically demanding
and very electron rich bisphosphines facilitate the catalytic
reaction. Lowering the catalyst loading of 6 to 1 mol% led to
a slight decrease in catalytic activity yielding dodecane in
87% yield (Table 1, entry 16). In solvents such as CH2Cl2 and
MeOH the catalyst was almost inactive (Table 1, entries 19
and 20).
The new alkyl Mn(I) complexes fac-[Mn(dpre)(CO)3(R)] (R
CH3 (3), CH2CH3 (4), CH2CH2CH3 (5)) and fac-
=
[Mn(dippe)(CO)3(CH2CH2CH3)] (6) were obtained by
treatment of fac-[Mn(dpre)(CO)3(Br)] (1) and fac-
[Mn(dippe)(CO)3(Br)] (2) with NaK (3 equiv) and subsequent
addition of CH3I, CH3CH2Br, and CH3CH2CH2Br, respectively,
in moderate to good isolated yields (Scheme 3). The hydride
complex fac-[Mn(dpre)(CO)3(H)] (10) was obtained by
reacting
a
suspension of [Mn2(CO)10] and 1,2-
bis(dipropylphosphino)ethane in anhydrous n-pentanol at
140oC for 5 h in low yield. All alkyl complexes are bench-
stable for at least 4 weeks in the presence of air. They were
1
fully characterized by H, 13C{1H} and 31P{1H} NMR and IR
spectroscopy, and high-resolution mass spectrometry. In
addition, the molecular structure of 6 was determined by X-
ray crystallography. A structural view is depicted in Scheme
3 with selected bond distances and angles given in the
caption.
Scheme 4. Mn(I) Complexes Tested as Catalysts
R
CH2CH2CH3
H
CO
CO
CO
Mn
CO
P
Mn
CO
P
Mn
CO
P
P
Scheme
3.
Synthesis
of
fac-
P
P
CO
CO
CO
[Mn(R2PCH2CH2PR2)(CO)3(R’)] (3-6) and Structural View
of 6 showing 50 % Ellipsoids (Most H Atoms Omitted for
Clarity).a
6
7
3 R = CH3
4 R = CH2CH3
5 R = CH2CH2CH3
CH3
CH3
CO
H
R'
CO
Br
CO
1. NaK
THF, 25 oC, 24 h
Mn
CO
OC
Mn
N
CO
Mn
CO
P
CO
CO
R2
P
R2
P
N
OC
Mn
CO
P
Mn
CO
CO
CO
2. R'X (X = I or Br)
THF, 25 oC, 10 min
CO
PR2
PR2
CO
R = nPr, R' = CH3 (64%)
CO
8
9
10
3
4
5
6
1
2
R = nPr
R = iPr
R = nPr, R' = CH2CH3 (12%)
R = nPr, R' = CH2CH2CH3 (32%)
R = iPr, R' = nPr (67%)
Having determined 6 as the most active catalyst and to
prove its general applicability, various substrates have been
tested to establish scope and limitations (Table 2). The
a Selected bond distances (Å) and angles (o): Mn1-C15 2.187(1),
Mn1-C18 1.803(1), Mn1-C19 1.799(1), Mn1-C20 1.798(1), Mn1-
P1 2.3224(5), Mn1-P2 2.3324(5), P1-Mn1-P2 85.53(2).
substrate scope was expanded to
monosubstituted alkenes, 1,1-disubstituted alkenes and cis-
and trans-1,2-disubstituted alkenes. Tri- and
a
variety of
tetrasubstituted alkenes could not be hydrogenated.
Terminal alkenes and allylic alcohols 12-22 as well as the
1,1-disubstituted alkenes 23 and 26 were readily reduced to
The catalytic performance of complexes 3-6 and the
known Mn(I) complexes fac-[Mn(dippe)(CO)3(H)] (7),19
[Mn(CO)5(CH3)] (8)20 and fac-[Mn(bipy)(CO)3(CH3)] (9)21 as
well as fac-[Mn(dpre)(CO)3(H)] (10)22 was then investigated
o
the corresponding alkanes in 83-99% yields at 25 C with a
ACS Paragon Plus Environment

Page 3 of 8
ACS Catalysis
catalyst loading of 2 mol%, 50 bar hydrogen pressure,
butanal is hydrogenated under the reaction conditions) as
detected by 1H and 13C{1H} NMR spectroscopy. This was
demonstrated by reacting 6 with H2 (50 bar) both in the
absence and presence of (4-methyl)styrene (3 equiv) (see
supporting information) clearly showing that migratory
insertion of the propyl group into a manganese carbonyl
bond took place.
The free energy profile calculated for the catalytic reaction
is depicted in Figure 2. Starting point is the hydride olefin
complex F which is the active species of the catalytic
reaction. In the first step of the reaction the hydride
migrates to the internal olefin C-atom resulting in an alkyl
1
2
3
4
5
6
7
8
reaction times between 18 to 24 h in diethyl ether as solvent
(Table 2). The only exception is 4-vinylpyridine (24) where
the yield was only 39%. There was no indication of
polymerization of this thermally unstable substrate
underlining the mild reaction conditions of the catalytic
protocol. In the case of 26, only the terminal double bond
was hydrogenated. Complete hydrogenation of internal
alkenes such as trans- and cis-stilbenes (28, 29) and cyclic
substrates such as 1H-indene (27), furan-2,5-dione (31), 2-
ethoxy-3,4-dihydro-2H-pyran (27) and 1,5-cyclooctadiene
(33) could be achieved although a higher temperature (60
oC) was required. In the case of (E)-4-phenylbut-3-en-2-one
(34) also the carbonyl moiety was hydrogenated. The
catalytic protocol shows high functional group tolerance
and halides, hydroxy groups, ethers, esters and even very
sensitive anhydrides were well tolerated. No reaction took
place with alkenes bearing carboxylic acid (35) and nitrile
(36) moieties, respectively.
The reaction mechanism was explored in detail by means
of DFT calculations,24 with propene taken as substrate and 6
(A in the calculations) as pre-catalyst. The free energy
profile for the initiation process, where the active catalyst is
formed, is depicted in Figure 1. The first step is the
migration of the CH2CH2CH3 ligand in complex A to the
carbonyl C-atom of an adjacent CO ligand. This occurs in an
easy step with a barrier of only 11 kcal/mol producing
intermediate B, an acyl species stabilized by an agostic C-H
bond. This transformation is slightly endergonic by 6
kcal/mol. Addition of dihydrogen affords complex D bearing
a 2-H2 ligand. Coordination of H2 has a barrier of 9
kcal/mol (TSCH) and a free energy balance of ΔG = 7
kcal/mol, from the pair of molecules in C to the dihydrogen
complex D. Finally, H-atom transfer from dihydrogen to the
C-atom of the acyl ligand produces E, a C-H σ-complex of
butanal. This last step has a barrier of only 3 kcal/mol and it
is thermoneutral. The catalytically active species F results
from ligand exchange from butanal to one molecule of
propene which is thermodynamically very favorable by -15
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
complex stabilized by
a C-H agostic interaction in
intermediate G. This is a very facile step with a barrier of
merely 1 kcal/mol and a favorable free energy balance of
ΔG = -5 kcal/mol. The following step corresponds to
dihydrogen coordination restoring a saturated coordination
environment around the metal in intermediate I. The overall
barrier for H2 coordination from intermediate G to the
dihydrogen complex I is 12 kcal/mol which is the highest
one along the path. In the last step of the mechanism H-
atom transfer from the dihydrogen ligand to the alkyl C-
atom (a formal protonation) regenerates a hydride and
forms the final product that remains weakly coordinated as
a C-H σ-ligand in intermediate J. This last step has
negligible barrier (5 kcal/mol) and is strongly exergonic with
ΔG = -25 kcal/mol. Closing of the catalytic cycle brings J
back to F with liberation of propane and coordination of a
new propene molecule in a favorable process with ΔG = –13
kcal/mol.
H
H
0.97
2.50
H
H
H
1.76
CO
P
H
1.62
Mn
CO
TSHI
H
CO
P
P
P
Mn
Mn
CO
CO
P
P
CO
TSIJ
2
5
TSFG
H
H
H
H
F
+ H2
I
-1
-2
-2
P
H
H
Mn
G
-3
H
H
CO
4.59
P
H
-7
H
CO
H
P
Mn
H
P
P
Mn
CO
Mn
CO
CO
P
CO
J
P
P
P
CO
CO
kcal/mol.
P
Mn
CO
-28
H
CO
H
H
H
O
O
P
P
C
P
C
Mn
CO
H
G = -13 kcal/mol
Mn
CO
CH2Et
CH2Et
H
CO
Et
O
CO
C
C
P
+ CH2=CHMe
- CH3CH2CH3
P
TSDE
16
Mn
CO
TSCH
15
CO
P
D
E
TSAB
11
Figure 2. Free Energy Profile Calculated for the
Hydrogenation of Propene. Free Energies (kcal/mol) are
Referred to fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6) (A in the
calculations)
13
13
+ CH2=CHMe
- CH3CH2CH2CHO
+ H2
B
6
C
6
H
H
H
O
H
O
H
H
P
P
C
H
F
P
P
C
A
0
Mn
H
Et
O
Mn
CO
C
CH2Et
CO CH2Et
-2
CO
CO
P
C
O
CH2Et
CO
Mn
CO
H
CO
C
CH2Et
P
P
P
Mn
CO
Mn
P
P
CO
P
Mn
CO
P
CO
CO
In sum, an efficient additive-free manganese-catalyzed
hydrogenation of alkenes to alkanes with molecular
hydrogen is described. To the best of our knowledge, this is
the first example of a well-defined Mn(I)-based catalyst for
the reduction of unactivated C=C bonds with dihydrogen.
The most efficient pre-catalyst is the alkyl bisphosphine
Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)] which is
air-stable for several weeks. The catalytic process is initiated
by migratory insertion of a CO ligand into the Mn-alkyl
CO
Figure 1. Free Energy Profile Calculated for the Formation
and Hydrogenolysis an Acyl Intermediate. Free Energies
(kcal/mol) are Referred to fac-[Mn(dippe)(CO)3(CH2CH2CH3)]
(6) (A in the calculations).
Preliminary experimental mechanistic studies revealed that
n-butanol is liberated during the catalytic reaction (n-
ACS Paragon Plus Environment

ACS Catalysis
Page 4 of 8
(3) Gieshoff, T. N.; Jakobi von Wangelin, A. In Non-Noble
bond to yield an acyl intermediate which undergoes rapid
hydrogenolysis to form the active 16e- Mn(I) hydride
catalyst [Mn(dippe)(CO)2(H)] - a conceptually new approach
in Mn(I) hydrogenation chemistry. We were able to
hydrogenate a range of mono- and disubstituted alkenes to
afford alkanes in good to excellent yields with high
functional group tolerance. The hydrogenation of
monosubstituted alkenes and 1,1-disubstituted alkenes
1
2
3
4
5
6
7
8
Metal Catalysis: Molecular Approaches and Reactions Klein
Gebbink, R. J. M.; Moret, M.-E., Eds.; Wiley-VCH: Weinheim,
2019; Chapter 5, pp 97-126.
(4) Castro, L. C. M.; Li, H.; Sortais, J.-B.; Darcel, C. When Iron
Met Phosphines: A Happy Marriage for Reduction Catalysis
Green Chem. 2015, 17, 2283-2303.
(5) (a) Bauer, I.; Knölker, H.-J. Iron Catalysis in Organic
Synthesis. Chem. Rev. 2015, 115, 3170-3387. (b) Fürstner, A.
Iron Catalysis in Organic Synthesis: A Critical Assessment of
What It Takes To Make This Base Metal a Multitasking
Champion. ACS Cent. Sci. 2016, 2, 778-789.
(6) Zell, T.; Milstein, D. Hydrogenation and Dehydrogenation
Iron Pincer Catalysts Capable of Metal-Ligand Cooperation by
Aromatization/Dearomatization Acc. Chem. Res. 2015, 48, 1979-
1994.
(7) Chakraborty, S.; Bhattacharya, P.; Dai, H.; Guan, H. Nickel
and Iron Pincer Complexes as Catalysts for the Reduction of
Carbonyl Compounds. Acc. Chem. Res. 2015, 48, 1995-2003.
(8) Mukherjee, A.; Milstein, D. Homogeneous Catalysis by
Cobalt and Manganese Pincer Complexes ACS Catal. 2018, 8,
11435−11469.
(9) Kallmeier, F.; Kempe, R. Manganese Complexes for
(De)Hydrogenation Catalysis: A Comparison to Cobalt and Iron
Catalysts. Angew. Chem., Int. Ed. 2018, 57, 46-60.
(10) Filonenko, G. A.; van Putten, R.; Hensen, E. J. M.; Pidko, E.
A. Catalytic (De)hydrogenation Promoted by Non-Precious
Metals - Co, Fe and Mn: Recent Advances in an Emerging Field.
Chem. Soc. Rev. 2018. 47, 1484-1515.
(11) Gorgas, N.; Kirchner, K. Isoelectronic Manganese and Iron
Hydrogenation/Dehydrogenation Catalysts - Similarities and
Divergences Acc. Chem. Res. 2018, 51, 1558-1569.
o
proceeds at 25 C, while 1,2-disubstituted alkenes require a
reaction temperature of 60 oC. In all cases, a catalyst loading
of 2 mol % and a hydrogen pressure of 50 bar was applied.
DFT calculations disclosed a typical inner shell mechanism
with all reacting fragments coordinated to the metal. The
path involves protonation of the internal C=C carbon atom
followed by hydride insertion into the Mn–C bond of the
resulting alkyl.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ASSOCIATED CONTENT
Supporting Information
The Supporting Information is available free of charge on
the ACS Publications website at DOI:
X-ray crystallographic data for 6 (CCDC entry 1920413).
(CIF)
Synthetic procedures, 1H, 13C{1H}, and 31P{H} NMR
spectra of all compounds, crystallographic data and
complete computational details (PDF)
Cartesian coordinates for DFT-optimized structures (XYZ)
AUTHOR INFORMATION
(12) (a) Chirik, P. J. Iron- and Cobalt-Catalyzed Alkene
Hydrogenation: Catalysis with Both Redox-Active and Strong
Field Ligands Acc. Chem. Res. 2015, 48, 1687−1695. (b) Arevalo,
R.; Chirik, P. J. Enabling Two-Electron Pathways with Iron and
Cobalt: From Ligand Design to Catalytic Applications J. Am.
Chem. Soc. 2019, 141, 9106−9123.
Corresponding Author
* E-mail (K. Kirchner): karl.kirchner@tuwien.ac.at, Tel: (+43) 1
58801 163611. Fax: (+43) 1 58801 16399.
ORCID
(13) For recent examples of iron, cobalt, and nickel catalyzed
olefin hydrogenations, see: (a) Murphy, L. J.; Ferguson, M. J.;
McDonald, R.; Lumsden, M. D.; Turculet, L. Synthesis of
Bis(phosphino)silyl Pincer-Supported Iron Hydrides for the
Catalytic Hydrogenation of Alkenes Organometallics 2018, 37,
4814−4826. (b) Sunada, Y.; Ogushi, H.; Yamamoto, T.; Uto, S.
Sawano, M.; Tahara, A.; Tanaka, H.; Yoshihito Shiota, Y.;
Yoshizawa, K.; Nagashima, H. Disilaruthena- and Ferracyclic
Complexes Containing Isocyanide Ligands as Effective Catalysts
for Hydrogenation of Unfunctionalized Sterically Hindered
Alkenes J. Am. Chem. Soc. 2018, 140, 4119−4134. (c) Xu, R.;
Chakraborty, S.; Bellows, S. M.; H.; Cundari, T. R.; Jones, W. D.
Iron-Catalyzed Homogeneous Hydrogenation of Alkenes under
Mild Conditions by a Stepwise, Bifunctional Mechanism ACS
Catal. 2016, 6, 2127−2135. (d) Friedfeld, M. R.; Shevlin, M.;
Margulieux, G. W.; Campeau, L.-C.; Chirik, P. J. Cobalt-Catalyzed
Enantioselective Hydrogenation of Minimally Functionalized
Alkenes: Isotopic Labeling Provides Insight into the Origin of
Stereoselectivity and Alkene Insertion Preferences J. Am. Chem.
Soc. 2016, 138, 3314−3324. (e) Tokmic, K.; Markus, C. R.; Zhu, L.;
Fout, A. R. Well-Defined Cobalt(I) Dihydrogen Catalyst:
Experimental Evidence for a Co(I)/Co(III) Redox Process in Olefin
Hydrogenation J. Am. Chem. Soc. 2016, 138, 11907−11913. (f)
Sandl, S.; Maier, T. M.; van Leest, N. P.; Kröncke, S.; Chakraborty,
Berthold Stöger: 0000-0002-0087-474X
Luis F. Veiros: 0000-0001-5841-3519
Karl Kirchner: 0000-0003-0872-6159
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT
Financial support by the Austrian Science Fund (FWF) is
gratefully acknowledged (Project No. P29584-N28). LFV
acknowledges Fundação para a Ciência e Tecnologia,
UID/QUI/00100/2013. This paper is dedicated to Professor
Johannes Fröhlich on the occasion of his 60th birthday.
REFERENCES
(1) Bullock, R. M. (Ed.), Catalysis without Precious Metals,
Wiley-VCH: Weinheim, 2010. I
(2) Blaser, H.-U.; Spindler, F.; Thommen, M. In The Handbook
of Homogeneous Hydrogenation; de Vries, J. G., Elsevier, C. J.,
Eds.; Wiley-VCH: Weinheim, 2008; Chapter 37, pp 1279−1324.
ACS Paragon Plus Environment

Page 5 of 8
ACS Catalysis
U.; Demeshko, S.; Koszinowski, K.; de Bruin, B.; Meyer, F.;
(18) Ojima, I.; Tsai, C.-Y.; Tzamarioudaki, M.; Bonafoux, D. The
Hydroformylation Reaction; Wiley: New York, 2004.
(19) Garduño, J. A.; Garcia, J. J. Non-Pincer Mn(I)
Organometallics for the Selective Catalytic Hydrogenation of
Nitriles to Primary Amines ACS Catal. 2018 9, 392-401.
(20) Coffield, T. H.;.Closson, R. D; Kozikowski, J. Acyl
Manganese Pentacarbonyl Compounds J. Org. Chem. 1957, 22,
598.
1
2
3
4
5
6
7
8
Bodensteiner, M.; Herrmann, C.; Wolf, R.; Jacobi von Wangelin,
Cobalt-Catalyzed Hydrogenations via Olefin Cobaltate and
Hydride Intermediates A. ACS Catal. 2019, 98, 7596-7606. (g)
Wang, Y.; Kostenko, A.; Sheglai Yao, S.; Driess, M. Divalent
Silicon-Assisted Activation of Dihydrogen in
a
Bis(N-
heterocyclic silylene)xanthene Nickel(0) Complex for Efficient
Catalytic Hydrogenation of Olefins J. Am. Chem. Soc. 2017, 139,
13499−13506. (h) Léonard, N. G.; Chirik, P. J. Air-Stable
α-Diimine Nickel Precatalysts for the Hydrogenation of
Hindered, Unactivated Alkenes ACS Catal. 2018, 8, 342−348.
(14) Garbe, M.; Junge, K.; Beller, M. Homogeneous Catalysis by
Manganese-Based Pincer Complexes. Eur. J. Org. Chem. 2017,
4344-4362.
(15) Maji, B.; Barman, M. Recent Developments of Manganese
Complexes for Catalytic Hydrogenation and Dehydrogenation
Reactions. Synthesis 2017, 49, 3377-3393.
(16) (a) Chakraborty, U.; Reyes-Rodriguez, E.; Demeshko, S.;
Meyer, F.; Jacobi von Wangelin, A. A Manganese Nanosheet:
New Cluster Topology and Catalysis Angew. Chem. Int. Ed.
2018, 57, 4970-4975. (b) Chakraborty, U.; Demeshko, S.; Meyer,
F.; Jacobi von Wangelin, A. Synthesis and Reactivity of an Early-
Transition-Metal Alkynyl Cubane Mn4C4 Cluster Angew. Chem.
Int. Ed. 2019, 58, 3466 –3470.
(21) Alonso, F. J. G.; Llamazares, A.; Riera, V.; Vivanco, M. Effect
of a nitrogen-nitrogen chelate ligand on the insertion reactions
9
of carbon monoxide into
a
manganese-alkyl bond
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Organometallics 1992 11, 2826-2832.
(22) Weber, S.; Stöger, B.; Kirchner, K. Hydrogenation of
Nitriles and Ketones Catalyzed by an Air-Stable Bisphosphine
Mn(I) Complex Org. Lett. 2018 20, 7212-7215.
(23) Andersen, J.-A. M.; Moss, J. R. Synthesis of an Extensive
Series of Manganese Pentacarbonyl Alkyl and Acyl Compounds:
Carbonylation and Decarbonylation Studies on [Mn(R)(CO)5]
and [Mn(COR)(CO)5] Organometallics 1994, 13, 5103-5020.
(24) (a) Parr, R. G.; Yang, W. Density Functional Theory of
Atoms and Molecules; Oxford University Press: New York, 1989.
(b) Calculations performed at the PBE0/(SDD, 6-31G**) level
using the GAUSSIAN 09 package. All calculations included
solvent effects (diethyl ether) using the PCM/SMD model. A full
account of the computational details and a complete list of
references are provided as SI.
(17) Calderazzo, F. Synthetic and Mechanistic Aspects of
Inorganic Insertion Reactions. Insertion of Carbon Monoxide
Angew. Chem. Int. Ed. 1977, 16, 299-311.
ACS Paragon Plus Environment

ACS Catalysis
Page 6 of 8
Table 1 Catalyst Screening for the Synthesis of Dodecane from 1-Dodecenea
1
cat
(X), 50 bar H2
2
3
4
solvent, temperature,18 h
11
entry catalyst
X (mol%) solvent T (oC) yield (%)b
1
2
3
4
5
6
7
8
fac-[Mn(dpre)(CO)3(CH3)] (3)
fac-[Mn(dpre)(CO)3(CH2CH3)] (4)
fac-[Mn(dpre)(CO)3(CH2CH2CH3)] (5)
fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)
fac-[Mn(dippe)(CO)3(H)] (7)
[Mn(CO)5(CH3)] (8)
fac-[Mn(bipy)(CO)3(CH3)] (9)
fac-[Mn(dpre)(CO)3(H)] (10)
fac-[Mn(dpre)(CO)3(CH3)] (3)
fac-[Mn(dpre)(CO)3(CH2CH3)] (4)
fac-[Mn(dpre)(CO)3(CH2CH2CH3)] (5)
fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)
fac-[Mn(dpre)(CO)3(CH2CH3)] (4)
fac-[Mn(dpre)(CO)3(CH2CH2CH3)] (5)
fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)
fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)
fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)
fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)
fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)
fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)
2
2
2
2
4
4
4
4
2
2
2
2
2
2
2
1
1
1
2
2
toluene 100
toluene 100
toluene 100
toluene 100
toluene 100
toluene 100
toluene 100
toluene 100
99
99
99
99
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
9
Et2O
Et2O
Et2O
Et2O
Et2O
Et2O
Et2O
Et2O
THF
40
40
40
40
25
25
25
25
25
25
25
25
10
11
12
13
14
15
16
17
18
19
20
99
99
99
99
87
82
84
<5
<5
DME
MeOH
CH2Cl2
aReaction conditions: 1-dodecene (0.56 mmol), 50 bar H2, 5 mL toluene or diethyl ether, 18 h. Yield determined by H NMR
analysis using methyl benzoate as standard.
b
1
ACS Paragon Plus Environment
6

Page 7 of 8
ACS Catalysis
Table 2 Hydrogenation of Various Alkenes Catalyzed by fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6)a
1
2
3
4
R1
6
(2 mol%), 50 bar H2
R
R1
R1
or
R1
or
R
R2
or
or
R2
R2
Et2O, 25-60 oC, 18-24 h
R2
_______________________________________________________________________________________
5
6
7
8
OH
R
Br
OH
Ph
12
13
14
R = C8H17 >99%
R = C14H25 >99%
R = C16H27 >99%
15
16
17
18
9
>99%
>99%
>99%
>99%
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
EtOOC COOEt
N
R
23
24
39%d
25
75%b
26
19
R = H >99%
>99%c
>99%c
20
R = CH3 >99%
R = C4H9; 83%
b
21
22
b
R = Cl; 88%
OH
O
O
O
27
28
>99%e
29
>99%e
30
>99%e
31
>99%e,f
>99%e
O
O
N
O
O
HO
32
>99%e
33
70%b,e
34
>99%e
35
36
no reactione
no reactione
aReaction conditions: substrate (0.56 mmol), fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (6) (2 mol%), 5 mL of diethyl ether, 50 bar H2,
o
b
c
d
1
25 C, 18 h, isolated yields. Conversion determined by GC-MS. 24 h. Yield determined by H NMR analysis using methyl
benzoate as standard. e60°C, 24 h. fTHF/CH2Cl2 (1:1) as solvent.
ACS Paragon Plus Environment
7

ACS Catalysis
Page 8 of 8
Table of Contents (TOC)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ACS Paragon Plus Environment
8