Chiral [2.2]paracyclophane-based NAC- and NHC-gold(I) complexes Dedicated to Prof. Hubert Schmidbaur on the occasion of his 80th birthday.

Article abstract of DOI:10.1016/j.jorganchem.2015.03.010

From enantiomerically pure, planar chiral [2.2]paracyclophane amines a series of nitrogen acyclic carbenegold(I) complexes and nitrogen heterocyclic carbenegold(I) complexes are prepared by a modular template synthesis using isonitriles and amines. These

Full text of DOI:10.1016/j.jorganchem.2015.03.010

Journal of Organometallic Chemistry xxx (2015) 1e8
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Chiral [2.2]paracyclophane-based NAC- and NHC-gold(I) complexes
a
a
a
b
€
Verena Goker , Simon Robert Kohl , Frank Rominger , Georg Meyer-Eppler ,
Lucia Volbach b, Gregor Schnakenburg c, Arne Lützen b, A. Stephen K. Hashmi a
Organisch-Chemisches Institut, Universitat Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
, d, *
a
€
b
ꢀ
€
Kekule-Institut für Organische Chemie und Biochemie, Universitat Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
c
€
Institut für Anorganische Chemie, Universitat Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
d Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
a r t i c l e i n f o
a b s t r a c t
Article history:
From enantiomerically pure, planar chiral [2.2]paracyclophane amines a series of nitrogen acyclic car-
benegold(I) complexes and nitrogen heterocyclic carbenegold(I) complexes are prepared by a modular
template synthesis using isonitriles and amines. These chiral catalysts are tested in two reactions, the
enantiotopos-selective furanyne cyclization and the enantioselective enyne cyclization. While excellent
conversions could be achieved with these new catalysts, the enantioselectivities in only some cases are in
the range of best known catalysts for these conversion.
Received 29 January 2015
Received in revised form
4 March 2015
Accepted 10 March 2015
Available online xxx
Dedicated to Prof. Hubert Schmidbaur on
the occasion of his 80th birthday.
© 2015 Elsevier B.V. All rights reserved.
Keywords:
Alkenes
Alkynes
Furans
Gold
Isonitriles
Carbene ligands
Introduction
in homogeneous gold catalysis were conducted with PCP-
phosphane ligands. So far, only silver and rhodium NHC com-
In both the inorganic and the organometallic chemistry of gold
the ligands play a pivotal role [1,2]. Metal complexes containing
paracyclophanes (PCPs) as ligands are already known [3e6]. Their
application as chiral catalysts is of significant interest as they
possess planar chirality. Gold complexes based on PCP were first
prepared in situ in 2011 by Michelet et al. [7]. These complexes
were used for the domino cyclization/nucleophile addition re-
actions of enynes in the presence of water, methanol, or electron-
rich aromatic derivatives, but the results concerning this reaction
using the famous PhanePhos ligand were unsatisfactory. In 2012,
plexes with PCP substructure have been reported [9], until now
there exist no N-hetereocyclic carbenegold complexes containing a
PCP substituent.
We now report the synthesis and application of the first PCP-
based NAC and NHC gold complexes.
Results and discussion
Synthesis and characterization
ꢀ
however, Gagne published a gold-catalyzed Cope rearrangement
The starting material for the synthesis of the new gold(I) com-
plexes was the PCP-amine 4, which was conveniently prepared in
enantiomerically pure form from the achiral PCP 1 in three steps by
published methods (Scheme 1) [10]: a simple electrophilic aro-
matic substitution provided the bromo-PCP 2, which then was
transferred into the azide 3 with n-BuLi and tosylazide. A reduction
with sodiumborohydride delivered racemic 4, whose enantiomers
were separated via HPLC on a CHIRALPAK IB column using n-hex-
ane/Isopropanol (75/25). The retention times on the analytical
where the highest yield and enantiomeric excess were found for
the PhanePhos ligand [8]. Both these innovative first investigations
€
* Corresponding author. Organisch-Chemisches Institut, Universitat Heidelberg,
Im Neuenheimer Feld 270, 69120 Heidelberg, Germany. Tel.: þ49 6221 548413;
fax: þ49 6221 544205.
E-mail address: hashmi@hashmi.de (A.S.K. Hashmi).
http://dx.doi.org/10.1016/j.jorganchem.2015.03.010
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V. Goker et al. / Journal of Organometallic Chemistry xxx (2015) 1e8
Scheme 1. Synthesis of the enantiomerically pure amine 4.
column were 10.75 min for the (þ)-enantiomer and 18.37 min for
the (ꢀ)-enantiomer. The absolute configuration of the first eluting
(þ)-enantiomer could then be assigned via X-ray diffraction of the
corresponding hydrochloride (Fig. 1) by analysis of the Flack
parameter (absolute structure parameter X ¼ 0.04(9)) [11].
The enantiomerically pure amine then was converted into the
isonitrile. The reaction of 4 with ethyl formate at reflux tempera-
ture delivered the formamide 5, which was purified by recrystal-
lization from acetone/pentane. 5 delivered the isonitrile (Sp)-6
when treated with phosphorylchloride and triethylamine in THF
(Scheme 2).
Finally, the synthesis of the nitrogen acyclic carbene (NAC)
complex [12] was achieved by reacting the simple (Me2S)gold(I)
chloride, isonitrile (Sp)-6, and a secondary amine which directly
lead to the desired gold complex (Sp)-7 in an excellent yield
(Scheme 3).
paracyclophane unit and the bis(phenylethyl) amine moiety. As
expected, the steric bulk of the chiral (S,S)-bisphenylethyl amine
moiety positions the PCP group syn to the gold centre on the car-
bene ligand. However, the low quality of the results doesn't allow a
detailed discussion. Hence, we take the results only as a proof of
constitution and configuration.
In addition to NAC-gold(I) complexes we also wanted to prepare
NHC-gold(I) complexes. This was achieved by employing the
functionalized amine building block 12 [13]. This amine gave the
NAC complex (Sp)-13 upon addition of the in situ-generated iso-
nitrilegold(I) chloride. The NAC ligand in the gold complex could
then be cyclized to the unsaturated NHC ligand bound to the gold
centre by a condensation and elimination reaction treatment
initiated by acid. In this way we were able to obtain the complexes
(Sp)-15 and (Sp)-16, the first one in low, the second one in high yield
(Scheme 4).
Different amines were tested in combination with (Sp)-6 in or-
der to demonstrate the broad scope of this methodology. Apart
from two achiral amines, which led to the enantiomerically pure
NAC-gold(I) complexes (Sp)-8 and (Sp)-9, also enantiomerically
pure amines were used. The latter provided NAC ligands which
combined planar and central chirality on each side of the NAC. Thus,
both diastereomers of 10 and complex 11 were obtained in good
yields. The excess of amine had to be removed by several washings
with hexane and recrystallization from DCM/hexane, which
reduced the yields shown in Fig. 2.
Synthesis of chiral gold(I) complexes without PCP ligands
In order to evaluate the influence of the PCP ligands on the
catalyst performance of the gold complexes we also prepared some
other chiral gold complexes that lack the PCP moiety as reference
catalysts: First (R)-17 (Fig. 4) was prepared according to the usual
method for the synthesis of NAC-gold(I) complexes.
ꢀ
As demonstrated by Gagne et al. [8], the dinuclear PCP-
substituted gold complex delivers the best enantiomeric excess
in Cope rearrangements. Thus, another target was the synthesis
of a dinuclear NAC gold complex. From binaphtyldiamine the
bis(isonitrile) was prepared by following the route described
above. Subsequently, with di-n-propylamine and (Me2S)gold(I)
chloride the complex (Sa)-18 was obtained in a good yield of 79%
(Fig. 5).
For 11 a suitable crystal for a single crystal X-ray structure
analysis could be grown. The structure of the complex is shown in
Fig.
3
[11], it confirmed the absolute configuration of the
As the corresponding chiral PCP-diamine was not available, it
was not possible to prepare a dinuclear PCP-substituted NAC-
gold(I) complex analogue in optically pure form.
Catalytic reactions
For the investigation of the catalytic activity in enantioselective
reactions two test reactions were selected. The first one is the
asymmetric phenol synthesis, which has already shown to give
some enantiomeric excess with phosphane ligands [14]. However,
so far chiral carbene complexes have not been tested in this reac-
tion. The substrate for this test reaction was prepared by following a
previously described route [14]. Deprotonation of the 2-
Fig. 1. Solid state molecular structure of (Sp)-4.
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V. Goker et al. / Journal of Organometallic Chemistry xxx (2015) 1e8
3
Scheme 2. Synthesis of the isonitrile.
The best ee value was obtained with silver triflate in chloroform.
Both transformations in DCM or in benzene (due to the melting
point of benzene this reaction had to be conducted at room tem-
perature), delivered similar ee values. In toluene only racemic
product was obtained, in methanol no conversion was detectable.
The different silver salts led to large differences in the ee values,
silver triflate showed the highest enantiomeric excess, 17%.
After the best conditions had been identified, the reaction was
conducted with both different chiral PCP-substituted gold com-
plexes and also with the chiral gold complexes without PCP-ligand
(Table 2).
(R)-(Sp)-10 shows a low ee of 21%, whereas the other diaste-
reomer (S)-(Sp)-10 only shows 5% ee, an interesting matched/mis-
matched situation. The other catalysts also provided unsatisfactory
ee values. The catalysis with the dinuclear (S)-18 also provided only
11% ee. Furthermore, there was no significant difference in ee for
PCP-substituted catalysts (Entries 1e8) and catalysts without PCP-
ligand (Entries 9 and 10). Also no significant differences between
the NAC- (Entries 1e6) and the corresponding NHC-ligands (Entries
7 and 8) were visible. On the other hand, the yields ranging from 87
to 97% were perfectly normal e different from the ee no reduction
in the yield was detected.
Scheme 3. Synthesis of the NAC-gold(I) complex (Sp)-7.
methylfuran (19) with n-BuLi and the subsequent reaction with
epichlorohydrin gave the epoxide 20. Reaction of the latter with
another equivalent of lithiated 19 provided alcohol 21, which finally
was propargylated to give rise to the furanyne substrate 22 in a
classical Williamson ether synthesis (Scheme 5).
Using catalyst (Sp)-7 we first optimized the reaction conditions
systematically in terms of the choice of the silver salt and the sol-
vent (Table 1).
Fig. 2. NAC-gold(I) complexes containing PCP substituents.
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V. Goker et al. / Journal of Organometallic Chemistry xxx (2015) 1e8
4
Fig. 4. Chiral complex (R)-17 lacking a PCP group.
Fig. 3. Solid state molecular structure of (S,S)-(Rp)-11.
The second test reaction was the addition of methanol to an
enyne substrate. With chiral NHC-gold complexes already good ee
values have been described [15,16].
The synthesis of this substrate was done in two steps starting
from 24. Deprotonation and prenylation yielded 41% of 25. Another
deprotonation followed by propargylation provided the catalysis
substrate 26 in good yield (Scheme 6) [17].
Fig. 5. Preparation of the dinuclear (Sa)-18.
Once more the best catalysis conditions with respect to silver
salt and solvent were screened. Initially the reaction was conducted
in methanol only, but this gave very low ee values, a solvent
mixture of five equivalents of methanol and a cosolvent was more
suitable. Benzene was quite successful, in addition silver hexa-
fluorophosphate was the best counter anion, 17% ee were obtained
(Entry 3). Apart from the reaction with silver hexafluoroantimonate
(Entry 7) the other silver salts gave similar ee values Table 3.
Now the different catalysts were investigated in the conversion
of 26 (Table 4). Quite different ee values were observed. Again, like
with substrate 22, the yield of 27 was very good. The best ee, 52%,
could be reached with the NAC-gold(I) complex (Sp)-8 (Entry 2).
In this reaction the ee values obtained with NAC-ligands (Entries
1, 2, 5 and 6) were higher than those of the gold complexes with
NHC-ligands (Entries 7 and 8). Similar to the conversions of test
substrate 22, a significant difference in the ee values obtained with
(R)-(Sp)-10 (Entry 5) and its diastereomer (S)-(Sp)-10 (Entry 4)
became visible. Surprisingly, (S)-18 (Entry 10) delivered only
racemic product.
Conclusion
We succeeded in the efficient preparation of a series of the first
planar-chiral PCP-substituted NAC- and NHC-gold(I) complexes as
well as 17, an NAC-complex with central chirality, and the dinuclear
gold(I) complex 18 with an axis of chirality. All these complexes
were tested as enantioselective catalysts in two reactions, a fur-
anyne cyclization and an enyne cyclization. With ee values of 21%
for the NAC-complex (R)-(Sp)-10 in the furanyne cyclization the
results are inferior to the known results with phosphane ligands
[14], with 52% for the NAC-complex (Sp)-8 the results in the enyne
cyclization are comparable to the values published for the best
NHC-gold(I) complex for this reaction [15,16].
All these results show the potential of the method for the
modular template synthesis of carbenegold(I) complexes. The chi-
ral groups used in this investigation still are not ideal for the re-
action types investigated.
Scheme 4. Synthesis of the NHC-complexes (Sp)-15 and (Sp)-16.
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V. Goker et al. / Journal of Organometallic Chemistry xxx (2015) 1e8
5
Scheme 5. Synthesis of substrate 22 bearing two enantiotopic furyl groups for the gold-catalyzed enantioselective phenol synthesis [14].
Experimental section
Table 1
Influence of the solvent and the counter anion on the conversion of 22.
General procedures (GPs)
General procedure 1 (GP 1): synthesis of PCP-substituted NAC-
gold(I) complexes
PCP-substituted NAC-gold(I) complexes were prepared accord-
ing to a literature procedure [12]. One equivalent of (DMS)AuCl was
dissolved in dry dichloromethane and one equivalent of PCP-
isocyanide was added at room temperature. Then the mixture
was stirred for 15 min. After that time 2 equivalents of the amine
were added. The mixture was stirred at room temperature and
protected from light for 1 h. The solution was filtered through celite
and the solvent removed under reduced pressure. The solid was
dissolved in DCM and pentane was added. The precipitate was
collected on a frit, washed with pentane and dried in vacuum to
afford the desired NAC gold complex as a colourless solid.
Entry
Catalyst
Solvent
Silver salt
Yield of 23
ee
1
2
3a
4
5
6
7
8
9
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
DCM
Chloroform
Benzene
AgPF6
AgPF6
AgPF6
AgPF6
AgPF6
AgSbF6
AgBF4
AgOTf
AgNTf2
81%
91%
71%
96%
e
4
5
4
rac
e
9
6
17
3
General procedure 2 (GP 2): synthesis of PCP-substituted NHC-
gold(I) complexes
PCP-substituted NHC-gold(I) complexes were prepared accord-
ing to a literature procedure. One equivalent of (SMe2)AuCl was
dissolved in dry dichloromethane and one equivalent of PCP-
isocyanide was added at room temperature and stirred for 15 min.
Then 2 equivalents of the amine were added. The mixture was
stirred at room temperature and protected from light for 1 h. Then
14 equivalents of HCl in dioxane were added. After completion
(monitored by TLC) of the reaction the mixture was filtered through
Celite and the solvent removed under reduced pressure. The pre-
cipitate was dissolved in DCM and pentane was added. The solid was
collected on a frit, washed with pentane and dried in vacuum to
afford the desired NHC gold complex as a colourless solid.
Toluene
Methanol
Chloroform
Chloroform
Chloroform
Chloroform
95%
98%
99%
95%
a
The reaction was conducted at RT.
Table 2
Catalyst screening in the gold-catalyzed cyclization of 22.
Synthesis of the carbene complexes
((Di-n-propylamino)((Sp)-[2.2]paracyclophaneamino)methylene)
gold(I) chloride (Sp)-7.
Entry
Catalyst
Yield of 23
ee
1
2
3
4
5
6
7
8
9
(Rp)-7
(Sp)-8
(Sp)-9
(S)-(Sp)-10
(R)-(Sp)-10
(R,S)-(Rp)-11
(Sp)-15
(Sp)-16
(R)-17
97%
93%
94%
93%
95%
87%
94%
96%
88%
93%
7%
9%
9%
5%
21%
2%
11%
5%
8%
11%
GP 1: (DMS)AuCl (50.0 mg, 170
acyclophane (40 mg, 170 mol), di-n-propylamine (35 mg,
340 mol), methylenechloride (3 mL), precipitation with methyl-
enechloride/pentane, colourless solid (88 mg, 155 mol, 92%).
mmol), (Sp)-4-isocyano[2.2]par-
m
m
10
(S)-18
m
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V. Goker et al. / Journal of Organometallic Chemistry xxx (2015) 1e8
Scheme 6. Synthesis of the second test substrate 26 [17].
CDCl3):
d
¼ 11.1 (q, 1C), 11.8 (q, 1C), 20.6 (t, 1C), 22.6 (t, 1C), 33.0 (t,
Table 3
Influence of the solvent and the counter ions in the test reaction with 26.
1C), 34.4 (t, 1C), 34.7 (t, 1C), 35.2 (t, 1C), 49.3 (t,1C), 61.4 (t, 1C),127.4
(d, 1C), 130.0 (d, 1C), 132.0 (d, 1C), 132.1 (d, 1C), 133.6 (d, 1C), 133.7
(d, 1C), 134.6 (s, 1C), 136.1 (d, 1C), 138.8 (s, 1C), 139.2 (s, 1C), 139.7 (s,
1C), 141.2 (s, 1C), 191.5 (s, 1C); MS [DART(þ)]: m/z (%) ¼ 566 (40)
[M]þ, 434 (35), 388 (100); HR-MS [FAB (þ)]: C23H30N2AuCl
(566.92), [C23H30N2AuCl]þ: calcd. 566.1763, found 566.1790.
((Dicyclohexylamino)((Sp)-[2.2]paracyclophaneamino)methylene)
gold(I) chloride (Sp)-8.
Entry
Catalyst
Solvent
Silver salt
Yield of 27
ee
1
2
3
4
5
6
7
8
9
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
(Sp)-7
Methanol
DCM
Chloroform
Benzene
Toluene
Dichlorethane
Benzene
Benzene
Benzene
Benzene
AgPF6
AgPF6
AgPF6
AgPF6
AgPF6
AgPF6
AgSbF6
AgBF4
AgOTf
AgNTf2
93%
97%
100%
98%
93%
89%
89%
97%
97%
96%
5%
11%
17%
23%
5%
4%
3%
13%
14%
12%
GP 1: DMSAuCl (63.0 mg, 214
cyclophane (50 mg, 214 mol), dicyclohexylamine (77.6 mg,
428 mol), DCM (3 mL), precipitation with DCM/Pentane, colour-
less solid (70 mg, 108
mmol), (Sp)-4-isocyano[2.2]para-
m
m
m
mol, 51%).
Mp/decomposition: 141 ꢁC; IR (ATR): nu ¼ 3795, 3708, 3280,
2926, 2852, 2349, 1529, 1493, 1447, 895, 718 cmꢀ1 1H NMR
;
10
(300 MHz, CDCl3):
d
¼ 1.25e1.55 (m, 8H), 1.66e1.69 (m, 2H),
1.83e1.99 (m, 8H), 2.06e2.09 (m, 2H), 2.86e2.95 (m, 2H),
2.97e3.20 (m, 7H), 3.30e3.36 (m, 1H), 6.33 (s, 1H), 6.50e6.66 (m,
7H); 13C NMR (150 MHz, CDCl3):
d
¼ 25.1 (t, 2C), 26.5 (t, 6C), 30.9 (t,
Table 4
Catalyst screening in the gold-catalyzed cyclization of 26.
2C), 31.3 (t,1C), 32.9 (t, 2C), 34.5 (t,1C), 34.8 (t,1C), 35.2 (t,1C),127.5
(d, 1C), 130.6 (d, 1C), 131.9 (d, 1C), 132.2 (d, 1C), 133.8 (d, 1C), 133.9
(d, 1C), 134.8 (s, 1C), 136.2 (d, 1C), 138.3 (s, 1C), 139.3 (s, 1C), 139.9 (s,
1C), 141.2 (s, 1C); MS [FAB(þ)]: m/z (%) ¼ 646 (69) [M]þ, 611 (100)
[MꢀCl]þ;
HR-MS
[FAB
(þ)]:
C29H38N2AuCl
(647.05),
[C29H38N2AuCl]þ: calcd. 646.2389, found 646.2415.
(Morpholino((Sp)-[2.2]paracyclophaneamino)methylene)gold(I) chlo-
ride (Sp)-9.
Entry
Catalyst
Yield of 27
ee
1
2
3
4
5
6
7
8
9
(Rp)-7
(Sp)-8
(Sp-)-9
(S)-(Sp)-10
(R)-(Sp)-10
(R,S)-(Rp)-11
(Sp)-15
(Sp)-16
(R)-17
97%
93%
94%
93%
95%
87%
94%
96%
88%
93%
33%
52%
7%
3%
36%
11%
19%
8%
20%
1%
10
(S)-18
GP 1: DMSAuCl (70 mg, 238
cyclophane (56 mg, 238 mol), morpholine (72 mg, 480
DCM (3 mL), precipitation with DCM/pentane, colourless solid
m
mol), (S)-4-isocyano[2.2]para-
m
mmol),
Mp/decomposition: 152 ꢁC; IR (ATR): nu ¼ 2961, 2928, 2873,
(57 mg, 103 mmol, 43%).
1541, 1350, 899, 748 cmꢀ1
;
1H NMR (300 MHz, CDCl3):
d
¼ 0.97 (t,
Mp/decomposition: 128 ꢁC; IR (ATR): nu ¼ 2924, 2852, 2466,
J ¼ 7.3 Hz, 3H), 1.12 (t, J ¼ 7.3 Hz, 3H), 1.71-1.90 (m, 4H), 2.80e3.19
(m, 7H), 3.31e3.41 (m, 2H), 3.49e3.59 (m, 1H), 3.84e4.01 (m, 2H),
6.37 (s, 1H), 6.46e6.63 (m, 6H), 7.08 (s, 1H); 13C NMR (150 MHz,
1572, 1495, 1395, 1109, 894, 718 cmꢀ1; 1H NMR (300 MHz, CD2Cl2):
d
¼ 2.83e2.92 (m, 2H), 2.94e3.20 (m, 6H), 3.64e3.69 (m, 2H),
3.80e3.88 (m, 4H), 4.18e4.35 (m, 2H), 6.26 (s, 1H), 6.51 (d,
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J ¼ 7.8 Hz, 2H), 6.59e6.67 (m, 4H), 7.31 (s, 1H); 13C NMR (150 MHz,
1H), 6.33 (dd, J ¼ 1.7 Hz, J ¼ 7.9 Hz, 1H), 6.36 (d, J ¼ 7.9 Hz, 1H), 6.43
(dd, J ¼ 1.7 Hz, J ¼ 7.9 Hz, 1H), 6.49 (dd, J ¼ 1.7 Hz, J ¼ 7.9 Hz, 1H),
6.93 (d, J ¼ 7.1 Hz, 1H), 7.00 (d, J ¼ 7.9 Hz, 1H), 7.30e7.45 (m, 7H),
7.51 (d, J ¼ 6.7 Hz, 1H), 7.72 (d, J ¼ 7.3 Hz, 2H); 13C NMR (150 MHz,
CD2Cl2):
d
¼ 33.0 (t, 1C), 34.2 (t, 1C), 34.6 (t, 1C), 35.0 (t, 1C), 56.7 (t,
2C), 65.6 (t, 1C), 67.2 (t, 1C), 127.3 (d, 1C), 130.1 (d, 1C), 131.8 (d, 1C),
132.3 (d, 1C), 133.6 (d, 1C), 133.8 (d, 1C), 135.7 (s, 1C), 136.1 (d, 1C),
138.5 (s, 1C), 139.5 (s, 1C), 139.7 (s, 1C), 141.7 (s, 1C), 190.4 (s, 1C); MS
[FAB(þ)]: m/z (%) ¼ 552 (47) [M]þ, 517 (100) [MꢀCl]þ; HR-MS [FAB
(þ)]: C21H24N2AuClO (552.85), [C21H24N2AuClO]þ: calcd. 552.1243,
found 552.1270.
CDCl3):
d
¼ 17.4 (q, 1C), 17.5 (q, 1C), 31.5 (t, 1C), 34.1 (t, 1C), 34.8 (t,
1C), 35.2 (t, 1C), 52.4 (d, 1C), 69.1 (d, 1C), 125.8 (d, 1C), 127.5 (d, 1C),
128.2 (d, 2C), 129.0 (d, 1C), 129.1 (d, 2C), 129.1 (d, 1C), 129.2 (d, 1C),
129.8 (d, 2C), 131.6 (d, 1C), 131.9 (d, 1C), 132.5 (d, 1C), 133.3 (d, 1C),
133.6 (d, 1C), 134.2 (s, 1C), 135.6 (d, 1C), 137.4 (s, 1C), 138.0 (s, 1C),
139.2 (s, 1C), 139.3 (s, 1C), 139.6 (s, 1C), 140.9 (s, 1C), 192.1 (s, 1C); MS
[FAB(þ)]: m/z (%) ¼ 690 (71) [M]þ, 655 (100) [MꢀCl]þ; HR-MS [FAB
(þ)]: C33H34N2AuCl (691.06), [C33H34N2AuCl]þ: calcd. 690.2076,
found 690.2066.
(Sp)-((Methyl(1-phenylethyl)amino)((S)[2.2]paracyclophaneamino)
methylene)gold(I) chloride (Sp)-10.
(1-Isopropyl-3-(Sp)-[2.2]paracyclophane-1H-imidazol-2(3H)-yli-
dene)gold(I) chloride (Sp)-15.
GP 2: DMSAuCl (45.0 mg, 152
cyclophane (35.5 mg, 152 mol), N-(2,2-dimethoxyethyl)propan-2-
amine (44.7 mg, 304 mol), DCM (3 mL), 4 M HCl in dioxane
(0.54 mL, 2.13 mmol), precipitation with DCM/pentane, colourless
mmol), (Sp)-4-isocyano[2.2]para-
GP 1: DMSAuCl (70.0 mg, 240
cyclophane (56 mg, 240 mol), di-n-propylamine (65 mg,
480 mol), methylenechloride (3 mL), precipitation with methyl-
mmol), (Sp)-4-isocyano[2.2]para-
m
m
m
m
enechloride/pentane, colourless solid (120 mg, 200 mmol, 84%).
crystals (15 mg, 27.2 mmol, 18%).
Mp: 147 ꢁC; IR (ATR): nu ¼ 3259, 2927, 2852, 1536, 1350, 1092,
Mp/decomposition: 140 ꢁC, IR (ATR): nu ¼ 3156, 3129, 2975,
772, 701 cm-1
;
1H NMR (300 MHz, CDCl3):
d
¼ 1.63 (d, J ¼ 7.0 Hz,
2931, 2851, 1597, 1498, 1433, 1409, 1230, 843, 749, 719 cmꢀ1 1H
;
3H), 2.85 (s, 3H), 2.88e3.22 (m, 7H), 3.36e3.47 (m, 1H), 6.1 (s, 1H),
NMR (600 MHz, CDCl3):
d
¼ 1.54 (d, J ¼ 6.7 Hz, 3H), 1.57 (d,
6.48e6.69 (m, 7H), 7.05 (s, 1H), 7.34e7.44 (m, 5H); 13C NMR
J ¼ 6.7 Hz, 3H), 2.91 (t, J ¼ 6.9 Hz, 2H), 3.00e3.19 (m, 6H), 5.21e5.28
(150 MHz, CDCl3, 298 K):
d
¼ 16.9 (q, 1C), 29.8 (q, 1C), 33.1 (t, 1C),
(m, 1H), 6.56e6.77 (m, 7H), 7.21 (s, 1H), 7.28 (s, 1H); 13C NMR
34.3 (t, 1C), 34.7 (t, 1C), 35.2 (t, 1C), 66.8 (d, 1C), 125.6 (d, 1C), 126.9
(d, 1C), 127.0 (d, 1C), 127.2 (d, 1C), 128.3 (d, 1C), 128.8 (d, 1C), 128.9
(d, 1C), 130.2 (d, 1C), 132.0 (d, 1C), 132.1 (d, 1C), 133.6 (d, 1C), 133.8
(d, 1C), 136.1 (d, 1C), 138.1 (s, 1C), 138.5 (s, 1C), 139.2 (s, 1C), 139.7 (s,
1C), 141.3 (s, 1C), 142.7 (s, 1C), 192.0 (s, 1C); MS [FAB(þ)]: m/z
(%) ¼ 600 (50) [M]þ, 565 (70) [MꢀCl]þ; HR-MS [FAB (þ)]:
(150 MHz, CDCl3):
d
¼ 23.4 (q, 1C), 23.5 (q, 1C), 32.7 (t, 1C), 34.9 (t,
1C), 35.1 (t, 1C), 35.3 (t, 1C), 54.1 (d, 1C), 116.9 (d, 1C), 122.5 (d, 1C),
126.7 (d, 1C), 129.9 (d, 1C), 132.6 (d, 1C), 132.9 (d, 1C), 133.3 (d, 1C),
134.0 (s, 1C), 134.6 (d, 1C), 137.2 (d, 1C), 137.8 (s, 1C), 139.4 (s, 1C),
139.5 (s, 1C), 141.4 (s, 1C), 170.7 (s, 1C); MS [FAB(þ)]: m/z (%) ¼ 548
(30) [M]þ, 513 (100) [MꢀCl]þ; HR-MS [FAB (þ)]: C22H24N2AuCl
(548.86), [C22H24N2AuCl]þ: calcd. 548.1294, found 548.1286.
C
26H28N2AuCl (691.06), [C26H28N2AuCl]þ: calcd. 600.1607, found
600.1601.
(1-Cyclododecyl-3-(Sp)-[2.2]paracyclophane-1H-imidazol-2(3H)-yli-
dene)gold(I) chloride (Sp)-16.
(((Sp)-[2.2]Paracyclophaneamino)(((S)-1-phenylethyl)((S)-1-
phenylethyl)amino) methylene)gold(I) chloride (Rp)-11.
GP 2: DMSAuCl (50 mg, 170
m
mol), (Sp)-4-isocyano[2.2]para-
mol), N-(2,2-dimethoxyethyl)cyclo-
mol), DCM (3 mL), 4 M HCl in dioxane
cyclophane (40 mg, 170
dodecanamine (93 mg, 340
m
m
(0.6 mL, 2.38 mmol), precipitation with DCM/pentane, colourless
GP 1: DMSAuCl (63.0 mg, 214
cyclophane (50 mg, 214 mol), bis-((S)-1-phenylethyl)amine
(147 mg, 651 mol), DCM (3 mL), precipitation with DCM/pentane,
m
mol), (Sp)-4-isocyano[2.2]para-
solid (110 mg, 163 mmol, 97%).
m
Mp/decomposition: 150 ꢁC; IR (ATR): nu ¼ 3126, 2928, 2856,
m
1738, 1596, 1470, 1175, 944, 868, 719 cmꢀ1 1H NMR (500 MHz,
;
colourless solid (127 mg, 184
m
mol, 85%).
CDCl3):
d
¼ 1.33e1.55 (m, 16H), 1.65e1.79 (m, 4H), 2.08e2.13 (m,
Mp/decomposition: 178 ꢁC; IR (ATR): nu ¼ 3345, 2980, 2928,
2H), 2.85e2.95 (m, 2H), 3.02e3.21 (m, 6H), 5.11e5.13 (m, 1H),
2850, 1522, 1492, 1451, 700 cmꢀ1 1H NMR (300 MHz, CDCl3):
;
6.56e6.80 (m, 7H), 7.16 (s, 1H), 7.26 (s, 1H); 13C NMR (150 MHz,
d
¼ 1.85 (d, J ¼ 7.2 Hz, 3H), 2.05e2.13 (m, 1H), 2.08 (d, J ¼ 7.2 Hz,
CDCl3):
d
¼ 21.7 (t, 1 C), 21.8 (t, 1C), 23.1 (t, 1C), 23.2 (t, 1C), 23.4 (t,
3H), 2.31e2.35 (m, 1H), 2.55e2.60 (m, 1H), 2.65e2.70 (m, 1H),
2.94e3.07 (m, 4H), 5.06 (q, J ¼ 7.1 Hz, 1H), 5.53 (dd, J ¼ 1.7 Hz,
J ¼ 7.9 Hz, 1H), 6.17 (dd, J ¼ 1.7 Hz, J ¼ 7.9 Hz, 1H), 6.18 (d, J ¼ 1.6 Hz,
1C), 23.5 (t, 1C), 23.6 (t, 1C), 23.7 (t, 1C), 23.8 (t, 1C), 31.21 (t, 1C),
31.24 (t, 1C), 32.8 (t, 1C), 34.9 (t, 1C), 35.1 (t, 1C), 35.3 (t, 1C), 58.6 (d,
1C), 117.8 (d, 1C), 122.2 (d, 1C), 126.7 (d, 1C), 129.9 (d, 1C), 132.6 (d,
€
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8
1C), 132.9 (d, 1C), 133.2 (d, 1C), 134.0 (s, 1C), 134.5 (d, 1C), 137.2 (d,
1C), 137.8 (s, 1C), 139.3 (s, 1C), 139.5 (s, 1C), 141.4 (s, 1C), 171.3 (s, 1C);
MS [FAB(þ)]: m/z (%) ¼ 637 (30) [MꢀCl]þ, 502 (40); HR-MS
[FAB(þ)]: C31H40N2AuCl (673.08), [C31H40N2Au]þ: calcd. 637.2857,
found 637.2864.
2C),11.1 (q, 2C),19.4 (t, 2C), 22.3 (t, 2C), 49.6 (t, 2C), 61.4 (t, 2C),124.1
(d, 2C),125.4 (d, 2C),125.6 (s, 2C),126.7 (d, 2C),128.4 (d, 2C),129.1 (d,
2C),129.8 (d, 2C),131.9 (s, 2C),132.2 (s, 2C),137.1 (s, 2C),189.9 (s, 2C);
MS [FAB(þ)]: m/z (%) ¼ 970 (20) [M]þ, 935 (40) [MꢀCl]þ; HR-MS
[FAB(þ)]:
C
34H42N4AuCl2 (971.56), [C34H42N4AuCl]þ: calcd.
935.2429, found 935.2408.
(R)-((1-Phenylethylamino)(piperidin-1-yl)methylene)gold(I) chloride
(R)-17.
Acknowledgements
The authors thank Umicore AG & Co. KG for the generous
donation of gold salts.
Appendix A. Supplementary material
CCDC 1051507 and 1045758 contain the supplementary crys-
tallographic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif.
GP 1: DMSAuCl (50.0 mg, 169
benzylisocyanate (22.3 mg, 169 mol), piperidine (28.9 mg,
339 mol), DCM (3 mL), precipitation with DCM/pentane, colour-
less solid (30 mg, 66.8
m
mol), (R)-(þ)-methyl-
m
m
mmol, 39%).
Mp/decomposition: 138 ꢁC; IR (ATR): nu ¼ 3156, 3129, 2975,
Appendix B. Supplementary data
2931, 2851, 1597, 1498, 1433, 1409, 1230, 843, 749, 719 cmꢀ1 1H
;
NMR (600 MHz, CDCl3):
d
¼ 1.58e1.62 (m, 2H), 1.65 (d, J ¼ 6.9 Hz,
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.jorganchem.2015.03.010.
3H), 1.88e1.91 (m, 4H), 3.26e3.34 (m, 2H), 4.11e4.17 (m, 2H), 5.71
(quint, J ¼ 6.9 Hz, 1H), 7.30 (sext, J ¼ 4.3 Hz, 1H), 7.36 (d, J ¼ 4.3 Hz,
4H); 13C NMR (150 MHz, CDCl3):
d
¼ 22.4 (t, 1C), 22.5 (q, 1C), 22.5 (t,
References
1C), 24.2 (t, 1C), 44.5 (t, 2C), 59.4 (d, 1C), 126.5 (d, 2C), 128.0 (d, 1C),
129.0 (d, 2C), 141.9 (s, 1C), 189.0 (s, 1C); MS [FAB(þ)]: m/z (%) ¼ 448
(25) [M]þ, 413 (100) [MꢀCl]þ; HR-MS [FAB (þ)]: C14H20N2AuCl
(448.74), [C14H20N2AuCl]þ: calcd. 448.0981, found 448.0975.
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(Sa)-18.
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charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data_request/cif
GP 1: DMSAuCl (49 mg, 160
binaphthyl (25 mg, 82 mol), di-n-propylamine (33 mg, 320
DCM (3 mL), precipitation with DCM/pentane, colourless solid
m
mol), (S)-2,20-diisocyano-1,10-
mol),
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m
m
€
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Mp/decomposition: 120 ꢁC; IR (ATR): nu ¼ 3259, 2927, 2852,
€
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1536, 1495, 1263, 1092, 792, 717 cmꢀ1; 1H NMR (500 MHz, CDCl3):
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13318e13322.
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Tetrahedron Lett. 51 (2009) 404e406.
d
¼ 0.87 (t, J ¼ 7.2 Hz, 6H), 0.89 (t, J ¼ 7.2 Hz, 6H), 1.22e1.30 (m, 4H),
1.57e1.68 (m, 4H), 2.56e2.70 (m, 4H), 3.51e3.60 (m, 2H), 4.11 (quint,
J ¼ 6.9 Hz, 2H), 6.73 (s, 2H), 7.27 (d, J ¼ 7.8 Hz, 2H), 7.42 (t, J ¼ 7.8 Hz,
2H), 7.55 (t, J ¼ 7.5 Hz, 2H), 8.01 (d, J ¼ 8.2 Hz, 2H), 8.10 (d, J ¼ 8.8 Hz,
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2H), 8.23 (d, J ¼ 8.8 Hz, 2H); 13C NMR (150 MHz, CDCl3):
d
¼ 10.7 (q,
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€
Please cite this article in press as: V. Goker, et al., Journal of Organometallic Chemistry (2015), http://dx.doi.org/10.1016/
j.jorganchem.2015.03.010