Mono- vs. dinuclear gold-catalyzed intermolecular hydroamidation

Article abstract of DOI:10.1002/ejoc.201402068

Mono- and dinuclear gold catalysts were investigated in the intermolecular hydroamidation of olefins. Upon activation of [Ph₃PAuCl] and [xantphos(AuCl)₂] with various silver salts (AgOTf, Ag[BF ₄], and Ag[SbF₆]), diverging reactivity of the resulting cationic gold complexes was observed. It was found that both the binding ability of the counterion and the solvent have a significant impact on the reactivity of the mono- and dinuclear complexes. Copyright

Full text of DOI:10.1002/ejoc.201402068

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FULL PAPER
DOI: 10.1002/ejoc.201402068
Mono- vs. Dinuclear Gold-Catalyzed Intermolecular Hydroamidation
Juan M. Serrano-Becerra,[a][‡] Alexander F. G. Maier,[a][‡] Sandra González-Gallardo,[b]
Eric Moos,[b] Christoph Kaub,[b] Maximilian Gaffga,[c] Gereon Niedner-Schatteburg,[c]
Peter W. Roesky,[b] Frank Breher,[b] and Jan Paradies*[a]
Keywords: Homogeneous catalysis / Gold / Hydroamination / Dinuclear complexes / Cooperative effects
Mono- and dinuclear gold catalysts were investigated in the
intermolecular hydroamidation of olefins. Upon activation of
[Ph3PAuCl] and [xantphos(AuCl)2] with various silver salts
(AgOTf, Ag[BF4], and Ag[SbF6]), diverging reactivity of the
resulting cationic gold complexes was observed. It was found
that both the binding ability of the counterion and the solvent
have a significant impact on the reactivity of the mono- and
dinuclear complexes.
Introduction
Results and Discussion
Multimetallic complexes have shown increased reactivity
combined with excellent dia- and stereoselectivity when
used as homogeneous catalysts in organic transforma-
tions.[1] Impressive examples are the rhodium-catalyzed hy-
droformylation by dinuclear complexes[2] or the activation
of alkynes by gold complexes.[3] In general, gold catalysis,[4]
and especially dinuclear gold complexes, have attracted sig-
nificant attention due to their high catalytic activity.[5–7]
Gold complexes have proved particularly suitable as cata-
lysts for the hydroamidation of olefins,[8,9,9b,10] allowing the
reaction to proceed even under mild conditions (60–90 °C).
Some intermolecular hydroamidations[11] have been re-
ported in which dinuclear gold complexes were used as cat-
alysts.[12] Although dinuclear gold catalysis has great poten-
tial, and synergistic interactions between the gold atoms
have been identified,[13] such an activation mode has not yet
been systematically investigated for hydroamidation reac-
tions.
As a benchmark reaction, we chose the addition of tosyl
amide (1) to cyclohexene (2) using the conditions reported
by He (Figure 1).[11a] We compared the [Ph3PAuCl] (3)/
AgOTf catalyst system (Scheme 1) with dinuclear gold com-
plexes derived from common bis(diphenylphosphanyl) li-
gands.[14] In these experiments, an increased reactivity of
[xantphos(AuCl)2] (4)/AgOTf in comparison to 3/AgOTf
was observed under the reported standard conditions (1:4,
1/2; 0.5 m, see the Supporting Information, Figure S1).
These promising results encouraged us to optimize the reac-
tion conditions. An almost stoichiometric reaction was pur-
sued by using a 1:1.5 ratio (1/2) of nucleophile to olefin
(Figure 1, a). Under these conditions, the reactions pro-
ceeded more slowly with both catalyst systems compared
with the reported conditions. However, the xantphos-based
dinuclear complex 4 (5 mol-%, corresponding to 10 mol-%
Au) provided the product 5 in 80% yield after 25 h, whereas
3 (10 mol-%) gave only 60% yield (Figure 1, a). Further op-
timization of the reaction conditions using 1,2-dichloro-
ethane (DCE) as solvent and higher concentration (3 m) al-
lowed the catalyst loading to be reduced to 4 mol-% for 3
and 2 mol-% for 4 with even shorter reaction times. Similar
yields (64 and 82%) were obtained within only 4 h com-
pared with 25 h (Figure 1, b), confirming the superior per-
formance of the dinuclear gold complex 4 when compared
with the mononuclear catalyst 3.
Here, we present a comparison of readily available mono-
nuclear gold complexes with their dinuclear counterparts in
the intermolecular hydroamidation of three selected olefins.
The influence of three counterions (OTf–, [BF4]– and
[SbF6]–) on the catalytic efficiency of the mononuclear and
the dinuclear catalysts was also investigated.
[a] Karlsruhe Institute of Technology (KIT), Institute for Organic
Chemistry,
Fritz-Haber Weg 6, 76131 Karlsruhe, Germany
E-mail: jan.paradies@kit.edu
Control experiments showed that the reaction did not
proceed in the absence of gold complexes. Two equivalents
of silver salts in combination with 4 were required for high
catalytic activity.[15] The catalytic hydroamination of cyclo-
hexene (2) with sulfonamide 1 using 2 mol-% 4 and 2 mol-
% AgOTf or Ag[SbF6] (2:1, Au/Ag) did not exceed 11%
yield of 5 after 5 h. Although the activity of silver com-
plexes in hydroamination reactions has been reported,[16]
the employed silver salts did not catalyze the reaction either
www.paradies-group.de
[b] Karlsruhe Institute of Technology (KIT), Institute for
Inorganic Chemistry,
Engesserstrasse 15, 76131 Karlsruhe, Germany
[c] Technical University of Kaiserslautern, Institute of Physical
Chemistry,
Erwin-Schrödinger-Straße, 67663 Kaiserslautern, Germany
[‡] Both author contributed equally.
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201402068.
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catalyzed hydroamidation[18] unlikely: Firstly, the efficiency
of the reaction of cyclohexene (2) with tosyl amide (1) is
phosphine-dependent.[19,20] The impact of the xanthene
backbone on the catalytic reaction was probed. Thus, we
synthesized xanthene-derived monophosphine[21] gold com-
plex 6 (Scheme 1), which was fully characterized and the
solid-state structure was established by single-crystal X-ray
diffraction. The molecular structure of 6 (Figure 2) is sim-
ilar to the molecular structure of [Ph3PAuCl],[22] exhibiting
exclusively κ1P-coordination. The P1–Au1 distance of
2.224(9) Å is comparable to that of the Ph3P-system
[2.232(4) Å], whereas the Au1–Cl1 distance is reduced by
18 pm to 2.273(1) Å. As anticipated, 6 and 3 exhibit iden-
tical catalytic performances when activated with AgOTf
(Figure 1, b), which can be attributed to their similar struc-
tures. Thus, it is reasonable to suggest that the increased
activity observed for 4 is a result of the spatial orientation/
proximity of the two gold atoms.
Figure 2. Molecular structure of 6 (hydrogen atoms are omitted for
clarity; thermal ellipsoids are drawn at the 50% probability level);
selected bond lengths and angles: P1–Au1 2.224(9) Å, Au1–Cl1
2.273(1 Å), P1–Au1–Cl1 178.3(2)°.
Secondly, substrates that form tertiary carbocations upon
protonation, e.g., 1-methylcyclohexene or 2-methylundec-1-
ene, undergo hydroamidation in low yield (see the Support-
ing Information Scheme S1a and b).[18b] Furthermore 3-
Figure 1. Hydroamidation of cyclohexene (2) with tosylamide (1);
conditions: AgX/Au, (1.1:1), 2 (1.5 equiv.), 1 (1.0 equiv.); X = OTf–
(solid line), [BF4]– (dotted line), [SbF6]– (dashed line). (a) X = OTf–;
10 mol-% 3 (triangles), 5 mol-% 4 (circles); 0.5 m; toluene; 85 °C;
(b) 4 mol-% 3 (triangles), 2 mol-% 4 (circles), 4 mol-% 6 (squares);
3.0 m; DCE; 85 °C; (c) X = [SbF6]–; 4 mol-% 3 (triangles); 2 mol-
% 4 (circles); 3.0 m; DCE; 85 °C and accessorily added substrates
(1.0 equiv. 1, 1.5 equiv. 2) after 120 min; yields were determined by
GC with dodecane as internal standard.
phenyl-1-propene,
a substrate that is susceptible to
Brønsted-acid catalyzed isomerization, was subjected the
gold-catalyzed hydroamidation with tosyl amide, however,
the reaction furnished exclusively the direct addition prod-
uct, and the byproduct arising from the addition of 1 to
isomerized starting material was not observed (see the Sup-
porting Information Figure S1, Scheme S1c).
Thirdly, we compared the efficiency of the gold-catalysts
with the various Brønsted-acid catalysts, e.g., HOTf,
H[BF4], H[PF6], HNTf2, and H[SbF6] in the hydroamid-
ation of 2 with 1 in toluene and 1,2-dichloromethane. The
reaction profiles of the Brønsted-acid catalyzed reaction
differ substantially from that of the gold-catalyzed reaction
(see the Supporting Information Figures S2–S4). Whereas
HOTf outperformed the gold-catalysts in toluene for the
reaction of 1 with 2, the reaction was faster with the gold-
catalysts in DCE (also in the presence of xantphos). In the
case of H[BF4], both gold catalysts displayed by far supe-
Scheme 1. Mono- and dinuclear gold complexes.
in the absence or presence of xantphos under the optimized rior reactivity in toluene and DCE. H[PF6] was ineffective
reaction conditions. This observation also suggests that as a Brønsted-acid catalyst in the hydroamidation of 1 with
HOTf, which is a catalyst for the hydroamidation, is not 2. The two gold catalysts were also ineffective, which can
generated in situ from the silver-mediated decomposition be explained by the formation of coordinatively saturated
of DCE.[17] Other observations render the Brønsted acid [(Ph3P)2Au]+ or ([xantphos)2Au2]+ species (see below). The
2
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Gold-Catalyzed Intermolecular Hydroamidation
activation of the gold-catalysts by AgNTf2 also furnished (cf. Figure 1, b, dashed line). On the other hand, density
catalytically inactive bisligated gold complexes (see below). functional theory (DFT) calculations predicted tighter
However, HNTf2 proved to be an efficient Brønsted-acid binding affinities to the [Ph3PAu]+ entity for the OTf– anion
catalyst for the hydroamidation of cyclohexene (2) by tosyl than for [BF4]–.[23] The increased rates of the dinuclear cata-
amide (1). Consequently, HNTf2 was not generated along lyst system 4, having OTf– as anion, strongly support an
the decomposition pathway of AgNTf2-activated gold com- activation step in which the substitution of an anion is facil-
plexes.
itated by the presence of the second metal center. Such pro-
Finally H[SbF6] was compared with the Ag[SbF6] acti- cesses are significantly influenced by the nature and polarity
vated gold complexes. The Brønsted-acid proved to be an of the solvent, giving rise to tight, loose, or solvent-sepa-
inefficient catalyst for the hydroamidation (16% after rated ion pairs with different catalytic reactivity. This may
90 min). In contrast, the gold complexes provided the prod- explain the rate increase when the solvent was changed to
uct in 90% yield after 90 min. The collected data supports a more polar one (toluene ε = 2.38; DCE ε = 10.42). Alter-
the conclusion that the hydroamidation of 2 with 1 is cata- natively, the toluene can coordinate to the electrophilic gold
lyzed by cationic gold-species.
center through the aromatic ring, competing with coordina-
One key step of the hydroamidation reaction is the acti- tion of the olefin.
vation of the double bond by cationic gold complexes.[23]
We then investigated whether the anion-dependent ac-
Consequently, catalysts containing strongly coordinating tivity of the gold-catalysts were also observable with other
anions[24] should display lower rates than catalysts with substrates. 1-Octene (7) was chosen as a challenging sub-
weaker coordinating anions. Indeed, the activation of the strate for the intermolecular hydroamidation, the transfor-
two precatalysts 3 and 4 by AgOTf, Ag[BF4], and Ag[SbF6] mation of which leads to a mixture of three isomers, which
led to very different kinetic profiles (Figure 1, b). Catalytic has also been observed in related gold-catalyzed addition
reactions employing [BF4]– as anion had higher initial rates reactions.[11a,26] Indeed, when 3 and 4 were employed as cat-
than those with OTf–. However, when [BF4]– was used, both alyst precursors in combination with the corresponding sil-
the mononuclear (3) and dinuclear (4) catalyst precursors ver salts, different reactivities were observed (Figure 3, a,
displayed identical productivity (68% after 4 h). The same solid, dotted, and dashed lines). In this case, [SbF6]– also
trend was observed for the Ag[SbF6]-activated catalysts, al- proved to be the best counterion for the transformation.
beit with dramatically increased reactivity. The intermo- The product 8 was obtained in 98 and 85% yield with 3
lecular hydroamidation using 3/Ag[SbF6] or 4/Ag[SbF6] as and 4, respectively (isolated yield of mixture of isomers af-
catalysts provided the product 5 in essentially quantitative ter 10.5 h: 99% for 3, 90% for 4). Using [BF4]– as anion,
yields [95 and 98% (GC yield); 99 and 99% (isolated yield)] lower yields (55 and 23%) were obtained, with the Ph3P-
within 4 h. The high catalytic activity of both gold com- system being the more active catalyst. Interestingly, when 3
plexes after Ag[SbF6]-activation was maintained during the or 4 were activated with AgOTf, comparable activities for
course of the reaction, as shown by the addition of an extra the two catalysts were observed. As a third olefin, we inves-
equivalent of olefin and nucleophile after 120 min (Fig- tigated norbornene (9) as substrate for the intermolecular
ure 1, c). The first equivalent of reactants (1.5 mmol 2, hydroamidation using only a 1.03:1.0 ratio of olefin to nu-
1.0 mmol 1) were consumed in the first half of the reaction, cleophile even at a reduced temperature of 75 °C (Figure 3,
giving rise to 72 and 84% yield for the first equivalents (36 b). The two catalyst precursors were employed in the reac-
and 42% overall yield; referenced to 2 mmol product 5; Fig- tion after activation with the corresponding silver salt. In
ure 1, c). After 120 min, a second equivalent of reactants all cases, the dinuclear complex showed the highest initial
was added and the hydroamidation product 5 was produced rates (Figure 3, b). The reactivity increased in the order
with the same efficiency (82% for both catalysts). The con- [BF4]– Ͻ OTf– Ͻ [SbF6]– for both catalysts. The mononu-
version of sequentially added starting material demon- clear Ph3P-system 3 displayed an induction period with all
strates the integrity of the catalytically active species over counterions. Interestingly, the reaction rate increased as
the reaction time. The small difference in reactivity (12%) soon as approximately 5% of the product was formed,
of the PPh3 and xantphos systems revealed in Figure 1 (b) which suggests that the product might be involved in a turn-
was attributed to changes in concentration upon addition over-limiting step, presumably the proton transfer. The re-
of a supplemental amount of substrate.
activity of the [SbF6]– and OTf– derived catalysts were com-
The dramatic change of reactivity of both [SbF6]-derived parable, whereas the [BF4]– system required 240 min for
catalysts may be understood in terms of the coordinating completion. In contrast, the dinuclear catalyst system 4/
ability of the anion. It is well-known that weakly coordinat- Ag[SbF6] produced the intermolecular hydroamidation
ing anions can be categorized by their fluoride ion affinity product 10 in quantitative yield (83% isolated yield) within
(FIA).[25] Accordingly, [SbF6]– (489 kJ/mol FIA) is a only 20 min.
weaker coordinating anion than [BF4]– (338 kJ/mol FIA).
Although the catalytic systems feature divergent reactiv-
Thus, the [SbF6]– anion is more easily replaced by an olefin ity, some mechanistic considerations can be made: (1) the
than [BF4]–, providing higher catalytic activity. In this case, hydroamidation reaction proceeds more efficiently in polar
the amount of catalytically active metal sites for the em- solvents: the stabilization of the cationic or dicationic metal
ployed systems 3/Ag[SbF6] and 4/Ag[SbF6] is identical (in complex is favored in a polar solvent and the replacement
both cases 4 mol-%), which leads to identical efficiencies by the olefin is facilitated. This is in agreement with the
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ever, the reaction of 4 with AgNTf2 or Ag[Al(OCH-
(CF3)2)4] resulted in decomposition to the previously re-
ported, coordinatively saturated, and thus catalytically inac-
2+
tive, [xantphos(Au)]2 dication 11 (31P{1H} NMR: δ =
34 ppm).[27] For comparison, [11](ClO4)2 was independently
accessed by the reaction of [Au(tht)ClO4] (tht = tetra-
hydrothiophene) with xantphos in 76% yield and was char-
acterized by crystal X-ray diffraction analysis (Figure 4).
The interatomic Au1–Au2 distance is slightly shorter in
[11](ClO4)2 than in the corresponding nitrate structure
(2.829(1) vs. 2.858(1) Å).[28] Both gold atoms are in an es-
sentially linear coordination environment, with P–Au–P
angles slightly smaller than 180° (163.50° and 164.53°). The
P–Au–P angle is distorted from the ideal 180° geometry by
16.50(6)° and 15.5(2)° [ref. P–Au–P 160.8(1)][28] due to the
attractive aurophilic Au–Au interaction.
Figure 4. Molecular structure of [xantphos(Au)]2(ClO4)2 (hydrogen
atoms, disordered counterion and solvent molecules are omitted for
clarity; thermal ellipsoids are drawn at the 50% probability level);
selected bond lengths and angles: Au1–Au2 2.829(1) Å, Au1–P2
2.328(2) Å, Au1–P4 2.331(2) Å, Au2–P3 2.319(2) Å, Au2–P1
2.333(2) Å, P1–Au2–P3 163.5(2)°, P2–Au1–P4 164.5(6)°.
Figure 3. (a) Hydroamidation of 1-octene (7) with tosylamide (1);
conditions: AgX/Au, (1.1:1), 7 (1.5 equiv.), 1 (1.0 equiv.); X = OTf–
(solid line), [BF4]– (dotted line), [SbF6]– (dashed line); 4.0 mol-% 3
(tringles); 2.0 mol-% 4 (circles); 3.0 m; DCE; 85 °C; (b) hydroamid-
ation of norbornene (9) with tosylamide (1); conditions: AgX/Au,
(1.1:1), 9 (1.03 equiv.), 1 (1.0 equiv.); X = OTf– (solid line), [BF4]–
(dotted line), [SbF6]– (dashed line); 2 mol-% 3 (triangles), 1.0 mol-
% 4 (circles); 3.0 m; DCE; 75 °C; yields were determined by GC
analysis with dodecane as internal standard.
To shed some light on the nature of the gold species in-
volved in the catalytic process, a series of 31P{1H} NMR
experiments were performed. The reaction of the mononu-
clear [xantphos(AuCl)][29] complex 12 with AgOTf fur-
observation that (2) more tightly binding anions diminish nished [11](OTf)2 exclusively, as evidenced by 31P NMR
the reaction rate. The FIA of [SbF6]– is higher than that of spectroscopy (Scheme 2). Consequently, cationic 12 can be
[BF4]–; thus the latter can be classified as a more tightly excluded as a potential catalytically active species. We then
binding anion, making its displacement by the olefin more turned our attention to the corresponding dinuclear gold
difficult. Hence, lower reaction rates were observed for both complex 4. The 31P{1H} NMR spectrum of the reaction
catalysts. The OTf– anion displays higher coordination abil- mixture of 4 with two equivalents of AgOTf featured three
ity than the other two counterions, resulting in lower reac- signals with chemical shifts of δ = 29.6, 20.0, and 17.0 ppm
tion rates for cyclohexene and 1-octene (cf. Figures 1 and (see the Supporting Information Figure S5). The resonance
2, a). Because cationic gold species are generated, which at δ = 20.0 ppm was assigned to the dicationic gold complex
are stabilized by the monophosphine PPh3 and by the rigid [xantphos(Au)2]2+ [28]
However, the complex nature of the
.
bisphosphine xantphos (3) the relative spatial orientation of mixture prevented the application of pulsed-gradient spin-
the metal atoms and the counterions is a determinant of echo (PGSE) diffusion experiments to establish the dinu-
the reactivity.
clear nature of the catalytically active species. In the absence
According to these considerations, the use of even of olefin and sulfonamide, the species decomposed within a
weaker binding anions such as Tf2N– or [Al(OCH- short time at room temperature (Figure S6). This decompo-
(CF3)2)4]– should result in even more active catalysts. How- sition is accompanied by the formation of a gold mirror
4
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and a decrease of intensity of the signal at δ = 20.0 ppm. cies is able to activate multiple bonds, as evidenced by ESI-
Concomitantly, among others, a broader signal appeared at MS and is tentatively assigned as the active species in the
δ = 34 ppm, which corresponds to the catalytically inactive hydroamidation.
dinuclear complex [xantphos(Au)]2X2,[27] as confirmed by
NMR experiments performed at 233 K. This decomposi-
tion pathway is known for the parent [Ph3PAu]+ system,
leading to catalytically inactive [(Ph3P)2Au]+. When either
olefin or nucleophile is added, a different composition of
mixture is observed. Whereas the olefin promotes the for-
mation of multiple species featuring signals at significantly
higher frequencies (δ Ͼ 40 ppm),[30] the addition of the nu-
cleophile stabilizes the dicationic species and prevents the
formation of the catalytically inactive [xantphos(Au)]22+ di-
cation 11 (Figures S7–S8).
Scheme 2. Formation of [11](OTf)2 from 12.
Figure 5. Hydroalkoxylation of phenylpropyne (13).
Finally, ESI-MS experiments were conducted with the
aim of characterizing the intermediates of the catalytic hy-
droamidation of cyclohexene (2) with tosylamide (1). How-
ever, conclusive results could not be obtained from analysis
Conclusions
of the reaction mixture. Nevertheless, the dinuclear 4/
Dinuclear dicationic [xantphos(Au)2]2+ serves as a start-
Ag[SbF6] system could be analyzed in the hydroalkoxyl- ing point for a tentative explanation for the observed reac-
ation of phenylpropyne (13) (Figure 5).[31] The mass spectra tivity. The increased reactivity of this species for selected
(positive ion mode) displayed signals at m/z 775 for substrates might be explained by increased electrostatic in-
[xantphos(Au)]+ and m/z 1007 for [xantphos(AuCl)(Au)]+. teractions with olefins or nucleophiles (evidenced by in-
As evidenced before, [xantphos(Au)]+ is not a competent creased stability of [xantphos(Au)2]2+ in the presence of 1).
catalyst for the hydroamination, and readily dimerizes in The propensity of the anion to coordinate to the cationic
solution (see Scheme 2). Likewise, [xantphos(AuCl)(Au)]+ gold centers accounts for counterion effects and can be
can be excluded as an active species because two equivalents compensated for by strong olefinic donors, e.g., cyclohexene
of silver salt are required for efficient hydroamidation reac- and norbornene. The location of anions in gold–olefin or
tion (see above). Remarkably, a signal at m/z 1119 was re- gold–alkyne complexes is dependent on both the coordi-
corded that was assigned to the monocationic dinuclear ge- nated ligand and the counterion.[24,33] For dicationic gold–
minal diaurated complex 14 (Figure 5).[32] Collision-in- olefin complexes this situation becomes even more pro-
duced dissociation experiments with mass-selected 14 nounced because two counterions must be accommodated
showed the loss of m/z 344 (assigned to [(C10H11O)(Au)]) in the outer coordination sphere, having a stronger impact
with a remaining complex at m/z 775 (assigned to [xant- on the reaction (as observed for OTf).
phos(Au)]+). An additional fragmentation channel showed
The catalytic intermolecular hydroamidation of olefins
the loss of m/z 359 (assigned to [((C10H11O)CH3)(Au)]), re- was developed by taking advantage of mononuclear and di-
sulting in a mass signal at m/z 760 (assigned to [(xantphos- nuclear catalyst systems. Our new system is active with a
CH3)(Au)]+) (see Figures S9–11, Supporting Information). reduced catalyst loading and at higher concentration. Un-
The observation of intermediate 14 confirms that [xant- precedented activity was observed for the reaction of nor-
phos(AuCl)2] is converted into the dicationic species upon bornene and sulfonamide catalyzed by the xantphos–gold
reaction with 2 equiv. Ag[SbF6], which is in accordance system. However, it was found that such accelerating effect
with the NMR experiments. This bimetallic dicationic spe- is highly sensitive to several factors, namely the chosen
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(97.0 mg, 1.03 mmol, 1.03 equiv.), or 1-octene (168 mg, 240 μL,
1.50 mmol, 1.50 equiv.) was added, followed by dodecane
(172.0 mg, 230 μL, 1.00 mmol, 1.00 equiv.) as internal standard and
the mixture was stirred for another 5–10 min. Finally, 1 (171.2 mg,
1.00 mmol, 1 equiv.) was added, the vial was sealed and immedi-
ately taken to 85 °C (75 °C in the case of norbornene) while stirring
for the time specified. To follow the formation of hydroamidation
products in real time, samples (ca. 40–50 μL) were taken at the
specified time intervals and immediately loaded on aluminum oxide
columns (ca. 2 cm) packed in Pasteur pipettes. A solution of the
reaction mixture was obtained by using EtOAc/Et2O (10 mL, 1:1
v/v) to carry the mixture throughout the short column and then a
sample was injected on the GC. Relative yields of products were
determined by comparison between the area corresponding to the
products and that of the dodecane.
anion, solvent, and substrate. The characterization of the
catalytically active species and its application in other trans-
formations will be the focus of future studies in our
laboratories.
Experimental Section
[Ph3PAuCl] (3), [xantphos(AuCl)2] (4), and [(4-(diphenylphos-
phanyl)-9,9-dimethylxanthene)(AuCl)] (6) were prepared according
to reported procedures[34] by the reaction of one equivalent
[(tht)AuCl] (tht = tetrahydrothiophene) per phosphino unit with
the corresponding phosphine.
[4-(Diphenylphosphanyl)-9,9-dimethylxanthene]AuCl (6): To a solid
mixture
of
4-(diphenylphosphanyl)-9,9-dimethylxanthene
N-Cyclohexyl-4-methylbenzenesulfoneamide (5): According to the
general procedure, the reaction of TsNH2 (1; 1.0 mmol) with cyclo-
hexene (2; 1.5 mmol) using the [xantphos(AuCl)2]/AgSbF6 catalyst
system composed of 4 (20.9 mg, 20.0 μmol, 2.00 mol-%) and
AgSbF6 (15.1 mg, 44.0 μmol, 4.40 mol-%), was stopped after
240 min and immediately subjected to column chromatography
using aluminum oxide as stationary phase (EtOAc/cyclohexane, 1:9
(1.0 equiv., 60 mg, 0.15 mmol) and (tht)AuCl (1.0 equiv., 48 mg,
0.15 mmol), anhydrous CH2Cl2 (7 mL) was added and the mixture
was stirred in the dark overnight. The solvent was removed in
vacuo and the solid was washed with a mixture of CH2Cl2 and
Et2O (1:10, 1.5 mL), to deliver the product as a white solid in quan-
1
titative yield (94 mg). H NMR (300 MHz, CDCl3): δ = 7.69–7.61
(m, 5 H), 7.56–7.43 (m, 6 H), 7.38–7.33 (m, 1 H), 7.12–7.03 (m, 3
1
1
2
2
to 1:4) to give 5 (244 mg, 0.97 mmol, 97%). H NMR (300 MHz,
H), 6.8 (ddd, J = 13.1, J = 7.3, J = 1.2 Hz, 1 H), 6.63–6.58 (m,
1 H), 1.61 (s, 6 H) ppm. 13C{1H} NMR (75 MHz, CDCl3): δ =
152.29 (d, JC,P = 3.7 Hz), 149.57, 134.29 (d, JC,P = 15.0 Hz),132.43
CDCl3): δ = 7.77 (d, J = 8.5 Hz, 2 H), 7.29 (d, J = 8.5 Hz, 2 H),
4.70 (d, J = 7.5 Hz,1 H, NH), 3.18–3.04 (m, 1 H, NCH), 2.42 (s, 3
H, CH3), 1.75–1.71 (m, 2 H), 1.67–1.59 (m, 2 H), 1.52–1.45 (m, 1
H), 1.28–1.02 (m, 5 H) ppm. 13C{1H} NMR (75 MHz, CDCl3): δ
= 143.21, 138.61, 129.74, 127.05, 52.68, 34.01, 25.26, 24.75,
21.64 ppm. MS (EI, 70 eV): m/z (%) = 254.1 (14) [M + H]+, 253.1
(100) [M]+, 210.0 (99), 155.0 (94) [C7H7O2S]+, 98.1 (60) [M–Ts:
C6H12N]+, 91.1 (53) [C7H7].
(d, JC,P = 7.5 Hz), 131.95 (d, JC,P = 2.8 Hz), 130.49 (d, JC,P
=
2.2 Hz), 129.76, 129.28 (d, JC,P = 12.3 Hz), 129.15, 128.30, 127.78,
125.52, 124.13, 123.47, 123.32, 116.62, 34.5 (d, JC,P = 1.1 Hz),
31.79 ppm. 31P{1H} NMR (101.2 MHz): δ = 26.07 (s) ppm. HRMS
(EI): m/z calcd. for C27H23POClAu [M]+ 626.0835; found 626.0832.
C27H23AuClOP (626.87): calcd. C 51.73, H 3.70; found C 51.48, H
3.71. Suitable crystals for X-ray diffraction analysis were obtained
from slow diffusion of pentane into a saturated solution of 6 in
CH2Cl2. Crystallographic data can be obtained free of charge from
the Cambridge Crystallographic database (CCDC-966105).
N-Tosyl-2-aminooctane, N-Tosyl-3-aminooctane, and N-Tosyl-4-
aminooctane (8): According to the general procedure, the reaction
of TsNH2 (1; 1.0 mmol) and 1-octene (7; 1.5 mmol) with the
[xantphos(AuCl)2]/AgSbF6 catalyst system consisting of (4;
20.9 mg, 0.020 mmol, 2.00 mol-%) and AgSbF6 (15.1 mg,
44.0 μmol, 4.40 mol-%) was stopped after 10.5 h and immediately
subjected to column chromatography using aluminum oxide as sta-
tionary phase (EtOAc/cyclohexane, 1:9 to 1:4) to give 8 (90% yield,
256 mg; 0.90 mmol) as a mixture of isomers. The ratio of isomers
was 1.7:1.5:1.0 as judged by the integration relative to the standard
using GC analysis. 1H NMR (300 MHz, CDCl3): δ = 7.70 (br. d, J
= 8.3 Hz, 2 H), 7.21 (br. d, J = 8.3 Hz, 2 H), 4.73 (app. t, J =
7.7 Hz, 1 H, NH), 3.20 (overlapped sept, J = 6.9 Hz, 1 H), 3.09
(overlapped sext, J = 6.4 Hz, 1 H), 3.06 (overlapped sext, J =
6.6 Hz, 1 H), 2.34 (s, 3 H, CH3), 1.42–1.05 (m, 10 H), 0.94 (d, J =
6.3 Hz, 3 H, CH3), 0.76 (overlapped t, J = 7.0 Hz, 3 H, CH3), 0.73
(overlapped t, J = 6.9 Hz, 3 H, CH3), 0.69 (overlapped t, J =
7.2 Hz, 3 H, CH3) ppm. 13C{1H} NMR (75 MHz): δ = 143.13,
143.07, 138.66, 138.64, 138.47, 129.64, 129.57, 127.14, 127.11,
55.45, 53.96, 50.07, 37.49, 37.27, 34.71, 34.43, 31.74, 31.61, 28.98,
27.86, 27.42, 25.52, 24.99, 22.60, 22.54, 22.51, 21.79, 21.55, 18.52,
14.12, 14.01, 13.95, 13.91, 9.64 ppm. MS (EI, 70 eV): m/z (%) =
283.2 (12) [M]+, 268.2(5) [M–CH3]+, 254.1 (73) [M–C2H5]+, 240.1
(40) [M – C3H7]+, 226.1 (45) [M – C4H9]+, 212.1 (57) [M – C5H11]+,
198.0 (100) [C9H12NO2S]+, 155.0 (84) [C7H7O2S]+, 91 (52) [C7H7].
[Xantphos(Au)]2[ClO4]2 [11](ClO4)2: Xantphos (1.00 equiv., 200 mg,
0.35 mmol) and [Au(tht)2]ClO4 (1.12 equiv., 160 mg, 0.39 mmol)
were dissolved in CH2Cl2 (10 mL) and the solution was stirred for
2 h in the dark. The solvent was concentrated (ca. 6 mL) under
vacuum and pentane (15 mL) was added to precipitate the product,
which was isolated as a white crystalline solid (230 mg, 0.13 mmol,
1
76% yield). H NMR (300 MHz, CDCl3): δ = 7.96 (m, 2 H), 7.67
(br. s, 2 H), 7.49 (m, 6 H), 7.25 (br. s, 4 H), 6.97 (m, 10 H), 6.25
(br. s, 2 H), 1.87 (br. s, 6 H) ppm. 13C{1H} NMR (75 MHz,
CDCl3): δ = 133.45, 133.05, 130.66, 130.32, 129.79, 35.32 ppm.
31P{1H} NMR (101.2 MHz): δ = 34.49 (br. s) ppm. HRMS (EI)
could not be obtained due to fast decomposition of 11 in the gas
phase. Suitable crystals for X-ray diffraction were obtained as col-
orless needles by slow diffusion of pentane into a solution of
[11](ClO4)2 in CH2Cl2. Crystallographic data can be obtained free
of charge from the Cambridge Crystallographic database (CCDC-
966106).
Catalytic Hydroamidation of Olefins. Typical Procedure: All experi-
ments were carried out on 1 mmol-scale of tosylamide (1). To a
solid mixture of the corresponding gold compound [Ph3PAuCl] (3;
19.8 mg, 0.040 mmol, 4.0 mol-%) or [xantphos(AuCl)2] (4; 20.9 mg,
0.020 mmol, 2.0 mol-%) and the corresponding silver salt (Au/Ag
N-(Bicyclo[2.2.1]heptane-2-yl)-4-methylbenzenesulfoneamide (10):
According to the general procedure, the reaction of TsNH2 (1;
=
1:1.1) AgOTf (11.3 mg, 44.0 µmol), AgSbF6 (15.1 mg,
44.0 µmol), or AgBF4 (8.6 mg, 44.0 µmol) in a 10 mL vial, anhy- 1.0 mmol) and norbornene (9; 1.03 mmol) using the [xant-
drous DCE (330 μL) under argon atmosphere was added and the
mixture was stirred for 30 min. The corresponding olefin cyclo-
hexene (123 mg, 152 μL, 1.50 mmol, 1.50 equiv.), norbornene
phos(AuCl)2]/AgSbF6 catalyst system composed of 4 (10.4 mg,
10.0 µmol, 1.00 mol-%) and AgSbF6 (7.56 mg, 22.0 μmol, 2.20 mol-
%) was stopped after 20 min and immediately subjected to column
6
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Job/Unit: O42068
/KAP1
Date: 03-06-14 19:04:15
Pages: 9
Gold-Catalyzed Intermolecular Hydroamidation
[7]
[8]
[9]
a) H. Davies, J. Briones, J. Am. Chem. Soc. 2013, 135, 13314–
13317; b) W. Zi, D. Toste, J. Am. Chem. Soc. 2013, 135, 12600–
12603.
a) R. A. Widenhoefer, X. Q. Han, Eur. J. Org. Chem. 2006,
4555–4563; b) T. E. Muller, K. C. Hultzsch, M. Yus, F. Foub-
elo, M. Tada, Chem. Rev. 2008, 108, 3795–3892.
a) X. Q. Han, R. A. Widenhoefer, Angew. Chem. Int. Ed. 2006,
45, 1747–1749; Angew. Chem. 2006, 118, 1779–1781; b) Z. B.
Zhang, C. Liu, R. E. Kinder, X. Q. Han, H. Qian, R. A. Wid-
enhoefer, J. Am. Chem. Soc. 2006, 128, 9066–9073; c) J. L.
Mcbee, A. T. Bell, T. D. Tilley, J. Am. Chem. Soc. 2008, 130,
16562–16571.
a) A. K. Mourad, J. Leutzow, C. Czekelius, Angew. Chem. Int.
Ed. 2012, 51, 11149–11152; Angew. Chem. 2012, 124, 11311–
11314; b) M. C. M. Higginbotham, M. W. P. Bebbington,
Chem. Commun. 2012, 48, 7565–7567; c) C. F. Bender, R. A.
Widenhoefer, Org. Lett. 2006, 8, 5303–5305; d) C. F. Bender,
R. A. Widenhoefer, Chem. Commun. 2006, 4143–4144; e) R. E.
Kinder, Z. Zhang, R. A. Widenhoefer, Org. Lett. 2008, 10,
3157–3159; f) Z. Zhang, C. F. Bender, R. A. Widenhoefer, J.
Am. Chem. Soc. 2007, 129, 14148–14149; g) Z. Zhang, C. F.
Bender, R. A. Widenhoefer, Org. Lett. 2007, 9, 2887–2889; h)
Z. Zhang, S. D. Lee, R. A. Widenhoefer, J. Am. Chem. Soc.
2009, 131, 5372–5373; i) P. de Fremont, E. D. Stevens, M. R.
Fructos, D.-R. M. Mar, P. J. Perez, S. P. Nolan, Chem. Com-
mun. 2006, 2045–2047; j) S. Gaillard, J. Bosson, R. S. Ramon,
P. Nun, A. M. Z. Slawin, S. P. Nolan, Chem. Eur. J. 2010, 16,
13729–13740.
chromatography using aluminium oxide as stationary phase
(EtOAc/cyclohexane, 1:9 to 1:4) to give 10 (221 mg, 0.83 mmol,
1
83% yield). H NMR (300 MHz, CDCl3): δ = 7.75 (d, J = 8.0 Hz,
2 H), 7.30 (d, J = 8.0 Hz, 2 H), 4.70 (d, J = 7.2 Hz, 1 H, NH),
3.14–3.08 (m, 1 H, NCH), 2.43 (s, 3 H, CH3), 2.18 (br. s, 1 H), 2.08
2
3
(br. s, 1 H), 1.58 (ddd, 1J = 12.9, J = 8.0, J = 2.5 Hz, 1 H), 1.42–
1.25 (m, 3 H), 1.18–0.91 (m, 4 H) ppm. 13C{1H} NMR (75 MHz):
δ = 143.34, 138.03, 129.79, 127.22, 56.78, 42.60, 40.89, 35.70, 35.30,
28.13, 26.44, 21.67 ppm. MS (EI, 70 eV): m/z (%) = 266.1 (15)
[M + H]+, 265.1 (69) [M]+, 210.0 (30), 184.0 (72), 155.0 (88)
[C7H7O2S]+, 133.0 (26), 110.1 (100) [M–Ts: C7H12N]+, 91 (87)
[C7H7]+, 81.0 (70).
[10]
Supporting Information (see footnote on the first page of this arti-
cle): Synthetic procedures, NMR spectroscopic data, kinetic data,
ESI-MS data, X-ray crystallographic data.
Acknowledgments
Financial support by the DFG-funded transregional collaborative
research center SFB/TRR 88 [Cooperative Effects in Homo- and
Heterometallic Complexes (3MET)] and the Helmholz-Research-
School (Energy-Related Catalysis; doctoral fellowship to C. K.) is
gratefully acknowledged. The Deutsche Forschungsgemeinschaft
(DFG) is acknowledged for a Heisenberg fellowship to J. P.
[11]
[12]
a) J. L. Zhang, C. G. Yang, C. He, J. Am. Chem. Soc. 2006,
128, 1798–1799; b) V. Lavallo, G. D. Frey, B. Donnadieu, M.
Soleilhavoup, G. Bertrand, Angew. Chem. Int. Ed. 2008, 47,
5224–5228.
[1] a) I. Bratko, M. Gomez, Dalton Trans. 2013, 42, 10664–10681;
b) E. K. van den Beuken, B. L. Feringa, Tetrahedron 1998, 54,
12985–13011; c) J. Park, S. Hong, Chem. Soc. Rev. 2012, 41,
6931–6943; d) M. Shibasaki, N. Yoshikawa, Chem. Rev. 2002,
102, 2187–2209.
[2] a) M. E. Broussard, B. Juma, S. G. Train, W. J. Peng, S. A.
Laneman, G. G. Stanley, Science 1993, 260, 1784–1788; b)
R. C. Matthews, D. K. Howell, W. J. Peng, S. G. Train, W. D.
Treleaven, G. G. Stanley, Angew. Chem. Int. Ed. Engl. 1996,
35, 2253–2256; c) W. J. Peng, S. G. Train, D. K. Howell, F. R.
Fronczek, G. G. Stanley, Chem. Commun. 1996, 2607–2608; d)
A. Zanardi, J. A. Mata, E. Peris, J. Am. Chem. Soc. 2009, 131,
14531–14537; e) S. Gonell, M. Poyatos, E. Peris, Angew. Chem.
Int. Ed. 2013, 52, 7009–7013; Angew. Chem. 2013, 125, 7147–
7151 .
[3] a) A. S. K. Hashmi, I. Braun, P. Nosel, J. Schadlich, M. Wie-
teck, M. Rudolph, F. Rominger, Angew. Chem. Int. Ed. 2012,
51, 4456–4460; Angew. Chem. 2012, 124, 4532–4536; b)
A. S. K. Hashmi, M. Wieteck, I. Braun, P. Nosel, L. Jongbloed,
M. Rudolph, F. Rominger, Adv. Synth. Catal. 2012, 354, 555–
562; c) Y. Oonishi, A. Gomez-Suarez, A. R. Martin, S. P. No-
lan, Angew. Chem. Int. Ed. 2013, 52, 9767–9771; d) A. S. K.
Hashmi, I. Braun, M. Rudolph, F. Rominger, Organometallics
2012, 31, 644–661.
[4] a) A. S. K. Hashmi, Chem. Rev. 2007, 107, 3180–3211; b) M.
Rudolph, A. S. K. Hashmi, Chem. Soc. Rev. 2012, 41, 2448–
2462; c) A. S. K. Hashmi, M. Rudolph, Chem. Soc. Rev. 2008,
37, 1766–1775; d) A. S. K. Hashmi, M. Wieteck, I. Braun, M.
Rudolph, F. Rominger, Angew. Chem. Int. Ed. 2012, 51, 10633–
10637; Angew. Chem. 2012, 124, 10785–10789; e) A. S. K.
Hashmi, T. Lauterbach, P. Nosel, M. H. Vilhelmsen, M. Ru-
dolph, F. Rominger, Chem. Eur. J. 2013, 19, 1058–1065; f) P.
Nosel, T. Lauterbach, M. Rudolph, F. Rominger, A. S. K.
Hashmi, Chem. Eur. J. 2013, 19, 8634–8641.
a) M. Kojima, K. Mikami, Synlett 2012, 57–61; b) R. L. La-
Londe, B. D. Sherry, E. J. Kang, F. D. Toste, J. Am. Chem. Soc.
2007, 129, 2452–2453; c) O. Kanno, W. Kuriyama, Z. J. Wang,
F. D. Toste, Angew. Chem. Int. Ed. 2011, 50, 9919–9922; Angew.
Chem. 2011, 123, 10093–10096; d) L. I. Rodriguez, T. Roth,
J. L. Fillol, H. Wadepohl, L. H. Gade, Chem. Eur. J. 2012, 18,
3721–3728; e) M. Rodriguez-Zubiri, C. Baudequin, A. Bethe-
gnies, J.-J. Brunet, ChemPlusChem 2012, 77, 445–454; f) C.
Sarcher, A. Luhl, F. C. Falk, S. Lebedkin, M. Kuhn, C. Wang,
J. Paradies, M. M. Kappes, W. Klopper, P. W. Roesky, Eur. J.
Inorg. Chem. 2012, 5033–5042.
E. Tkatchouk, N. P. Mankad, D. Benitez, W. A. Goddard,
F. D. Toste, J. Am. Chem. Soc. 2011, 133, 14293–14300.
V. Pawlowski, H. Kunkely, A. Vogler, Inorg. Chim. Acta 2004,
357, 1309–1312.
The hydroamination reaction of 1 with 2 in the presence of 4
activated with Ag[SbF6] (1 equiv.) only led to yields below 10%
of 5; ligand and silver effects have been identified in gold-cata-
lyzed transformations. For Ag effects, see: a) D. Wang, R. Cai,
S. Sharma, J. Jirak, S. K. Thummanapelli, N. G. Akhmedov,
H. Zhang, X. Liu, J. L. Petersen, X. Shi, J. Am. Chem. Soc.
2012, 134, 9012. For ligand effects, see: b) W. Wang, G. B.
Hammond, B. Xu, J. Am. Chem. Soc. 2012, 134, 5697; for a
review, see: D. J. Gorin, B. D. Sherry, F. D. Toste, Chem. Rev.
2008, 108, 3351.
a) J. W. Sun, S. A. Kozmin, Angew. Chem. Int. Ed. 2006, 45,
4991–4993; Angew. Chem. 2006, 118, 5113–5115; b) D. J. Ye,
X. Zhang, Y. Zhou, D. Y. Zhang, L. Zhang, H. S. Wang, H. L.
Jiang, H. Liu, Adv. Synth. Catal. 2009, 351, 2770–2778; c) V. R.
Bhonde, R. E. Looper, J. Am. Chem. Soc. 2011, 133, 20172–
20174; d) V. H. L. Wong, T. S. A. Hor, K. K. Hii, Chem. Com-
mun. 2013, 49, 9272–9274; e) D. Susanti, F. Koh, J. A. Kusuma,
P. Kothandaraman, P. W. H. Chan, J. Org. Chem. 2012, 77,
7166–7175; f) X. Giner, C. Najera, Synlett 2009, 3211–3213; g)
X. Giner, C. Najera, G. Kovacs, A. Lledos, G. Ujaque, Adv.
Synth. Catal. 2011, 353, 3451–3466; h) C. Michon, F. Medina,
F. Capet, P. Roussel, F. Agbossou-Niedercorn, Adv. Synth. Ca-
tal. 2010, 352, 3293–3305.
[13]
[14]
[15]
[16]
[5] A. Pradal, P. Y. Toullec, V. Michelet, Synthesis 2011, 1501–
1514.
[6] a) M. P. Munoz, J. Adrio, J. C. Carretero, A. M. Echavarren,
Organometallics 2005, 24, 1293–1300; b) M. J. Johansson, D. J.
Gorin, S. T. Staben, F. D. Toste, J. Am. Chem. Soc. 2005, 127,
18002–18003.
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Pages: 9
J. Paradies et al.
X. Zhang, A. Corma, Chem. Commun. 2007, 3080–3082.
G. Tarkanyi, P. Kiraly, G. Palinkas, A. Deak, Magn. Res.
Chem. 2007, 45, 917–924.
A. Deak, T. Megyes, G. Tarkanyi, P. Kiraly, L. Biczok, G. Pal-
inkas, P. J. Stang, J. Am. Chem. Soc. 2006, 128, 12668–12670.
H. Ito, T. Saito, T. Miyahara, C. M. Zhong, M. Sawamura,
Organometallics 2009, 28, 4829–4840.
FULL PAPER
[17] T. T. Dang, F. Boeck, L. Hintermann, J. Org. Chem. 2011, 76,
9353–9361.
[18] a) Z. G. Li, J. L. Zhang, C. Brouwer, C. G. Yang, N. W. Reich,
C. He, Org. Lett. 2006, 8, 4175–4178; b) D. C. Rosenfeld, S.
Shekhar, A. Takemiya, M. Utsunomiya, J. F. Hartwig, Org.
Lett. 2006, 8, 4179–4182.
[19] Asymmetric hydroamidations using chiral phosphine-stabilized
gold complexes have also been reported, see ref.[10g,10h,12b]
[20] a) J. Hannedouche, E. Schulz, Chem. Eur. J. 2013, 19, 4972–
4985; b) R. E. M. Brooner, R. A. Widenhoefer, Chem. Eur. J.
2011, 17, 6170–6178; c) G. Kovacs, A. Lledos, G. Ujaque, Orga-
nometallics 2010, 29, 5919–5926.
[26]
[27]
[28]
[29]
[30]
R. E. M. Brooner, T. J. Brown, R. A. Widenhoefer, Chem. Eur.
J. 2013, 19, 8276–8284.
ˇ
[31] J. Roithová, S. Janková, L. Jasˇíková, J. Vánˇa, S. Hybel-
bauerová, Angew. Chem. Int. Ed. 2012, 51, 8378–8382.
[21] M. J. L. Tschan, H. Launay, H. Hagen, J. Benet-Buchholz, [32] A. Zhdanko, M. E. Maier, Chem. Eur. J. 2014, 20, 1918–1930.
P. W. N. M. van Leeuwen, Angew. Chem. 2004, 116, 2116–2142;
M. J. L. Tschan, H. Launay, H. Hagen, J. Benet-Buchholz,
P. W. N. M. van Leeuwen, Chem. Eur. J. 2011, 17, 8922–8928.
[22] A. O. Borissova, A. A. Korlyukov, M. Y. Antipin, K. A. Lys-
senko, J. Phys. Chem. A 2008, 112, 11519–11522.
[23] G. Kovacs, G. Ujaque, A. Lledos, J. Am. Chem. Soc. 2008, 130,
853–864.
[24] D. Zuccaccia, L. Belpassi, A. Macchioni, F. Tarantelli, Eur. J.
Inorg. Chem. 2013, 4121–4135.
[25] I. Krossing, I. Raabe, Angew. Chem. Int. Ed. 2004, 43, 2066–
2090.
[33] a) G. Ciancaleoni, L. Biasiolo, G. Bistoni, A. Macchioni, F.
Tarantelli, D. Zuccaccia, L. Belpassi, Organometallics 2013, 32,
4444–4447; b) D. Zuccaccia, L. Belpassi, F. Tarantelli, A. Mac-
chioni, J. Am. Chem. Soc. 2009, 131, 3170–3171.
[34] R. Uson, A. Laguna, M. Laguna, D. A. Briggs, H. H. Murray,
J. P. Fackler, (Tetrahydrothiophene)gold(I) or Gold(III) Com-
plexes in Inorganic Syntheses, John Wiley & Sons, New York,
2007, p. 85–91.
Received: February 13, 2014
Published Online: ᭿
8
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Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O42068
/KAP1
Date: 03-06-14 19:04:15
Pages: 9
Gold-Catalyzed Intermolecular Hydroamidation
Gold-Catalyzed Hydroamination
J. M. Serrano-Becerra, A. F. G. Maier,
S. González-Gallardo, E. Moos, C. Kaub,
M. Gaffga, G. Niedner-Schatteburg,
P. W. Roesky, F. Breher,
J. Paradies* ...................................... 1–9
Mono- vs. Dinuclear Gold-Catalyzed In-
termolecular Hydroamidation
Dinuclear xantphos-derived gold com-
plexes were compared to the mononuclear
Ph3P-gold complex in the hydroamidation
of olefins. For some examples, higher
activity of the dinuclear gold complexes
was observed, suggesting cooperative acti-
vation of the substrates.
Keywords: Homogeneous catalysis / Gold /
Hydroamination / Dinuclear complexes /
Cooperative effects
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