Communication
Dalton Transactions
Table 2 Substrate Scope
Acknowledgements
This work was supported by the JSPS KAKENHI Grant
Numbers JP16H01038 and JP18H04268 in Precisely Designed
Catalysts with Customized Scaffolding and also by Grant-in-
Aid for Scientific Research (C) (15K05457 and 18K05152).
1
2
a,b
c
Entry
R
R
t (h) T (°C) Yield (%) E : Z
1
2
3
4
5
6
7
8
9
Ph
Ph
Ph
Ph
n-Bu
SiMe
1
10
1
30
30
30
30
30
30
70
70
70
70
70
>99
100 : 0
94 : 6
91 (9)
87 (12)
>99
3
100 : 0
85 : 15
100 : 0
100 : 0
90 : 10
98 : 2
72 : 28
65 : 35
27 : 73
n-Pr n-Pr
2
2
Notes and references
Ph
Ph
Ph
Ph
Ph
Ph
Ph
p-C
p-C
p-C
p-C
p-C
p-C
p-C
6
6
6
6
6
6
6
H
H
H
H
H
H
H
4
4
4
4
4
4
4
OMe
CH OH
>99
2
2
15
3
>99
95
>99
1
(a) J. Takaya and N. Iwasawa, J. Am. Chem. Soc., 2017, 139,
6074; (b) N. Hara, T. Saito, K. Semba, N. Kuriakose,
H. Zheng, S. Sakaki and Y. Nakao, J. Am. Chem. Soc., 2018,
NH
Br
2
COMe
89
39
73
67
1
0
1
NO
CN
2
90 (6)
66 (15)
140, 7070; (c) R. C. Cammarota and C. C. Lu, J. Am. Chem.
1
Soc., 2015, 137, 12486; (d) D. You, H. Yang, S. Sen and
F. P. Gabbaï, J. Am. Chem. Soc., 2018, 140, 9644;
a
1
b
Determined by H NMR. Yield in parenthesis is the yield of the
c
1
corresponding alkane. Determined by H NMR and/or GC.
(e) F. G. Fontaine and D. Zargarian, J. Am. Chem. Soc., 2004, 126,
8786; (f) M. Devillard, E. Nicolas, C. Appelt, J. Backs, S. Mallet-
Ladeira, G. Bouhadir, J. C. Slootweg, W. Uhl and D. Bourissou,
Chem. Commun., 2014, 50, 14805; (g) K. Kamikawa, Y.-Y. Tseng,
J.-H. Jian, T. Takahashi, T. Takahashi and M. Ogasawara, J. Am.
Chem. Soc., 2017, 139, 1545.
p-amino-substituted diphenylacetylene was also hydrogenated
to (E)-p-amino-stilbene in good yield and selectivity (entry 7);
the higher temperature (70 °C) and a longer reaction time
required for the conversion of this substrate might be due to
competitive coordination of the amino group to the cationic
iridium(III) centre. The reactions involving electron-withdrawing
p-acetyl-, p-nitro- and p-cyano-substituted diphenylacetylenes
were slow and exhibited low E : Z selectivity (entries 9–11),
which might be due to poor coordination ability of these elec-
tron-deficient alkynes (and Z-alkene intermediates derived
therefrom; see below) to the cationic iridium(III) catalyst.
2
3
P. Buchwalter, J. Rosé and P. Braunstein, Chem. Rev., 2015,
115, 28.
(a) W. E. Buhro, B. D. Zwick, S. Georgiou, J. P. Hutchinson
and J. A. Gladysz, J. Am. Chem. Soc., 1988, 110, 2427;
(
b) P. Braunstein and E. de Jésus, J. Organomet. Chem.,
1
4
989, 365, C19; (c) P. Mastrorilli, Eur. J. Inorg. Chem., 2008,
835; (d) L. Rosenberg, Coord. Chem. Rev., 2012, 256, 606.
4
(a) J. G. Planas, F. Hampel and J. A. Gladysz, Chem. – Eur.
J., 2005, 11, 1402; (b) V. S. Chan, I. C. Stewart,
R. G. Bergman and F. D. Toste, J. Am. Chem. Soc., 2006,
Complex 2 catalysed isomerization of (Z)-stilbene to (E)-stil-
bene under 1 atm H at 30 °C in EtOH (eqn (1)). In addition,
2
128, 2786; (c) P. E. Sues, A. J. Lough and R. H. Morris,
(
Z)-stilbene was detected at the initial stage of the hydrogen-
ation of diphenylacetylene and converted to (E)-stilbene
Fig. S27†). These observations suggest that the alkyne semi-
J. Am. Chem. Soc., 2014, 136, 4746; (d) Y. Gloaguen,
W. Jacobs, B. de Bruin, M. Lutz and J. I. van der Vlugt,
Inorg. Chem., 2013, 52, 1682.
(
hydrogenation by catalyst 2 proceeds via initial hydrogenation
12b,d,e
5 J. G. Planas and J. A. Gladysz, Inorg. Chem., 2002, 41, 6947.
to (Z)-alkenes followed by their isomerization to (E)-akenes.
6
L. Gelmini and D. W. Stephan, Organometallics, 1988, 7,
49.
8
ð1Þ
7
(a) S. Leelasubcharoen, P. A. Zhizhko, L. G. Kuzmina,
A. V. Churakov, J. A. K. Howard and G. I. Nikonov,
Organometallics, 2009, 28, 4500; (b) A. E. Findlay,
S. Leelasubcharoen, L. G. Kuzmina, J. A. K. Howard and
G. I. Nikonov, Dalton Trans., 2010, 39, 9264.
B. D. Zwick, A. M. Arif, A. T. Patton and J. A. Gladysz,
Angew. Chem., Int. Ed. Engl., 1987, 26, 910.
(a) A. Inagaki and M. Akita, Coord. Chem. Rev., 2010, 254,
In conclusion, we have synthesized the first phosphido
derivative of the (bpy) Ru(II) fragment, [RuP ], and established
2
2
its coordination behaviour as a bulky and strongly electron-
donating bidentate P-donor metalloligand. The potential
utility of this ligand in homogeneous catalysis has been
demonstrated by the efficient (E)-selective alkyne semi-hydro-
genation catalysed by the Ru–Ir complex 2. Future work will
8
9
1220; (b) Y. Halpin, M. T. Pryce, S. Rau, D. Dini and
focus on the synthesis of other [RuP
complexes and further elucidation of the functions of the
RuP ] ligand.
2
]-ligated transition metal
J. G. Vos, Dalton Trans., 2013, 42, 16243; (c) M. D. Kärkäs,
O. Verho, E. V. Johnston and B. Åkermark, Chem. Rev.,
[
2
2
014, 114, 11863; (d) K. Mori, M. Kawashima and
H. Yamashita, Chem. Commun., 2014, 50, 14501;
e) K. Murata, K. Saito, S. Kikuchi, M. Akita and A. Inagaki,
Chem. Commun., 2015, 51, 5717.
(
Conflicts of interest
1
0 (a) M. Osawa, M. Hoshino and Y. Wakatsuki, Angew. Chem.,
There are no conflicts to declare.
Int. Ed., 2001, 40, 3472; (b) S. Eller, B. Trettenbrein,
Dalton Trans.
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