A neutral Gold(III)-Boron transmetalation

Article abstract of DOI:10.1021/om400884s

The occurrence of direct transmetalation between gold(III) and boron species during gold-catalyzed cross-coupling reactions has recently become the subject of intense discussion. In this work, we investigate the transmetalation reaction between discrete, stable gold(III) complexes and boron reagents. Interestingly, electron-rich arylboronic acids remain unreactive under neutral conditions, whereas electron-deficient species undergo transmetalation in a highly efficient manner.

Full text of DOI:10.1021/om400884s

Communication
pubs.acs.org/Organometallics
A Neutral Gold(III)−Boron Transmetalation
Manuel Hofer,† Enrique Gomez-Bengoa,‡ and Cristina Nevado*,†
†Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
‡
́
́
Dpto. de Quımica Organica, Universidad del Paıs Vasco, Apt. 1072, 20080 San Sebastian, Spain
́
́
S
* Supporting Information
ABSTRACT: The occurrence of direct transmetalation between gold(III) and boron species during gold-catalyzed cross-
coupling reactions has recently become the subject of intense discussion. In this work, we investigate the transmetalation reaction
between discrete, stable gold(III) complexes and boron reagents. Interestingly, electron-rich arylboronic acids remain unreactive
under neutral conditions, whereas electron-deficient species undergo transmetalation in a highly efficient manner.
he exchange of organic ligands between two metallic
Tspecies, better known as transmetalation, is one of the key
steps in the course of metal-catalyzed cross-coupling reactions.
In particular, the transmetalation of boron species with Pd(II)
intermediates generated in a preceding oxidative addition step
has been studied in detail.1 It is widely recognized that B/
Pd(II) transmetalation is facilitated in the presence of an
inorganic base; however, the ultimate nature of the
intermediates shaping transmetalation reactions is still a matter
of lively discussions.2 Two mechanistic scenarios seem to
prevail: the first one relies on the formation of a “boronate”
intermediate (upon reaction of the inorganic base and the
boronic acid or ester), which then transfers its organic ligand to
the in situ generated Pd(II) intermediate.3 In contrast, recent
studies by Jutand,4 Hartwig,5 and Schmidt6 suggested the
formation of palladium−hydroxo species (generated by
reaction of the base with the Pd(II) intermediate) that will
then acquire the organic ligand from boron through an
associative mechanism. Compelling experimental and computa-
tional evidence has been gathered supporting the latter
pathway, although the inorganic nature of the base,7
heterogeneity in the reaction,8 and a scarce understanding of
the role played by the reaction’s byproducts9 make the
generalization of the mechanistic puzzle governing these
transformation a challenging task.
heteroatom bonds.11 In contrast to the widespread use of
Pd(II)/B transmetalation, the interaction of boron reagents
with other late transition metals, particularly gold, has been
much less studied.12
Seminal work by Schmidbaur and Fackler demonstrated that
aromatic−gold(I)−phosphine complexes could be obtained by
reaction of R3PAuX with sodium tetraphenylborate at room
temperature.13 A wider reaction scope, both on the ancillary
phosphine ligand bound to gold and on the aryl moiety that is
transferred, could be achieved with the use of CsCO3 in
isopropyl alcohol, as demonstrated by Gray14 and Hashmi.15
Recently, this methodology has been applied to the synthesis of
NHC−Au−aromatic compounds by Nolan and co-workers.16
Interestingly, control experiments seem to point toward the
formation of a NHC−Au−OH complex rather than a
“boronate” intermediate to explain the new C(sp2)−Au
bonds, in line with Pd(II)/B transmetalation processes
(Scheme 1, top).4−6
Scheme 1
In the past few decades, gold(I) complexes have arisen as
versatile tools to catalyze a wide variety of reactions involving
unsaturated moieties, due to their high carbophilic Lewis
acidity.10 For most of these transformations, the catalytic cycle
is terminated via protonolysis of C−Au(I) bonds to regenerate
the active species. However, more recently, the functionaliza-
tion of C−Au(III) bonds has concealed further attention, as
such intermediates could potentially offer an alternative, or at
the very least a complementary platform, to Pd(II)
intermediates for the efficient formation of C−C and C−
Received: September 6, 2013
Published: February 5, 2014
© 2014 American Chemical Society
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Communication
On the other hand, reactions combining [Au(I)] and
Selectfluor and an additional metal reagent (B, Si) have been
recently discovered.17 A representative example is the oxidative
carbo-heterofunctionalization of alkenes in the presence of
boronic acids reported by Zhang18 and Toste19 (Scheme 1,
bottom).
transmetalation under neutral conditions. When the reaction
mixture was heated to 150 °C for 9 h, complex 2 could not be
detected. Instead, decafluorobiphenyl (3) and Ph3PAuCl were
obtained in 89 and 91% yields, respectively (Scheme 2, eq 3).
Control experiments showed that heating isolated cis-2 to 150
°C gives 3 in 87% yield (vertical arrow), thus suggesting a
reductive elimination on 2 as the likely pathway for the
formation of the new C(sp2)−C(sp2) bond.23
In these transformations, activation of the double bond
seems to occur via gold(III) species which are formed in the
first step of the catalytic cycle by oxidation of the gold(I)
precatalyst with Selectfluor. Next, the intramolecular attack of a
N,O-nucleophile affords an alkyl−gold(III) intermediate, which
in the presence of aryl boronic acids reacts via transmetalation
followed by reductive elimination18 or through a bimolecular
reductive elimination to give the new C(sp3)−C(sp2) bonds.19
In the latter case, in the absence of base, the ability to build up a
strong B−F interaction in the transition state is key to
triggering the formation of a new C−C bond without a proper
transmetalation step. While the transmetalations of κ3-
(C∧N∧C)*Au(OX) complexes with aryl and heteroaryl boronic
acids in toluene are known to proceed smoothly,19j-l we decided
to study the reactivity of boron reagents with aryl gold(III)
dichloride complexes. We aimed not only to learn more about
this area of gold reactivity but also to gain knowledge that could
guide future gold-catalytic cross-coupling endeavors.
These results prompted us to examine the reactivity of
gold(III) complexes related to 1. Thus, cis-dichloro(2,4,6-
trifluorophenyl)(triphenylphosphine)gold(III) (4) was pre-
pared by the reaction of [AuI(2,4,6-C6F3H2)(PPh3)] with
PhICl2 in dichloromethane. The structure of 4 could be
confirmed by X-ray diffraction analysis (Figure 1).24
A
Our study commenced with cis-dichloro(pentafluorophenyl)-
(triphenylphosphine)gold(III) (1), which was prepared in high
yield by oxidation of the corresponding gold(I) complex
[AuI(C6F5)(PPh3)] in the presence of PhICl2 according to a
previously reported procedure.20 We hypothesized that the
gold(III) center, electron-deprived by the presence of an
electron-deficient aromatic ligand, would favor the trans-
metalation reaction with neutral boron species. However, the
reaction of 1 with phenylboronic acid under neutral conditions
returned only unreacted starting material at 25, 90, and 150 °C
despite long reaction times (>24 h) (Scheme 2, eq 1). In
Figure 1. X-ray structure of complex 4.
comparative analysis between the X-ray structures of complexes
120a and 424 in terms of distances and dihedral angles showed
interesting results. The chloride trans to the aromatic ligand
(Cl2) is bound more strongly than the chloride trans to the
phosphine ligand (Cl1) in compound 1.
In contrast, the opposite trend is observed in compound 4
bearing a trifluorobenzene residue, thus reflecting the less
electron deficient character of the trifluoro- vs the penta-
fluorobenzene ring (Table 1).
Scheme 2
The reaction of 4 in the presence of phenylboronic acid
under neutral conditions afforded, in analogy to the previous
case, unreacted starting material even at 150 °C (Table 2, entry
1). In contrast, the reaction with (pentafluorophenyl)boronic
acid delivered the corresponding octafluorobiphenyl (5) and
Ph3PAuCl in 94 and 92% yields, respectively (Table 2, entry 2)
as a result of Au(III)−B transmetalation followed by reductive
elimination. Similarly, the reaction with (trifluorophenyl)-
boronic acid resulted in the formation of the homocoupling
product 6 in good yield (Table 2, entry 3). These results also
rule out a potential transmetalation between two gold(III)
species, with the aryl groups hopping around prior to the
reductive elimination step. The reactions of 4 with the
corresponding ethylene glycol and pinacol boronic esters did
not proceed at all, and only starting materials were recovered
from the reaction mixtures, thus showing that the nature of the
boron reagent plays a key role in a successful transmetalation
process (Table 2, entries 4 and 5). A competition experiment
between complexes 1 and 4 in the presence of (C6F5)B(OH)2
was carried out. The reaction of 4 seems to be slightly favored
(1:1.4 ratio of 3 to 5; see the Supporting Information for
details), which could be related to the longer Au−Cl1 distance
in complex 4 in comparison to that in 1 (see Table 1) and/or
the easier reductive elimination on the putative bis-aryl
gold(III) intermediate preceding the formation of products 3
and 5, respectively.
contrast, the reaction of 1 with (pentafluorophenyl)boronic
acid at 150 °C for 2 h allowed us to isolate cis-chlorobis-
(pentafluorophenyl)(triphenylphosphine)gold(III) (cis-2) in
73% yield,20a,21 thus proving that transmetalation of discrete
gold(III) species with electron-deficient boronic acids can occur
under neutral conditions (Scheme 2, eq 2). The reaction also
returned minor amounts of decafluorobiphenyl (3) and
pentafluorobenzene as a result of reductive elimination on 2
and protodeborylation of the boron reagent under the reaction
conditions, respectively.22 To the best of our knowledge, this
result is one of the first examples of efficient gold(III)−B
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Communication
Table 1. Comparison of Complexes 1, 4, 7, and 8
bond (Å)/angle (deg)
entry
1
4
7
8
1
2
3
4
Au−Cl1
Au−Cl2
Au−C
2.3230(9)
2.3167(9)
2.029(3)
2.335(1)
2.343(1)
2.016(5)
87.2(1)
2.3464(7)
2.3241(8)
2.034(3)
81.47(8)
2.2710(6)
2.2806(6)
2.045(2)
87.04(7)
Cl1−Au−C
88.58(11)
transmetalation while the trans arrangement of the chloride
ligands eliminates the possibility of the competitive reductive
elimination observed for 7 (eq 5). A comparison between the
structural parameters of cis-[AuIII(C6F5)Cl2(PPh3)] (1) and cis-
[AuIII(C6F5)Cl2(PtBu3)] (7) is enlightening: the key Cl1−Au−
C(sp2) dihedral angle is reduced in the latter (88.58 vs 81.47°)
because of the large cone angle of P(tBu)3, thus explaining the
facile reductive elimination in 7 to form a new C(sp2)−Cl bond
(see Table 1). In addition, when the structural parameters of
[AuIII(C6F5)Cl2(PPh3)] (1) were compared with those of
[AuIII(C6F5)Cl2(IPr)] (8), decreasing bond angles were found.
The high steric demand of the ancillary ligand reduces the sum
of the angle of the other ligands and thus hinders trans-
metalation, in the order PtBu3 > IPr > PPh3. The Au−Cl bonds
in 8, corresponding to 2.271 and 2.281 Å, respectively, seem to
be stronger than those found in 1 (2.323, 2.317 Å), which
together with the steric bulk of the NHC ligand might explain
its lack of reactivity toward transmetalation.
Table 2. Transmetalation Studies on Complex 4
ab
,
ab
,
c
entry
R2, X
5
6
Ph3PAuCl
1
2
3
4
5
Ph, H
C6F5, H
94
92
91
d
2,4,6-C6F3H2, H
65
C6F5, −CH2CH2−
C6F5, −C(Me)2C(Me)2−
a
The reactions were carried out using 4 (1 equiv) and R2-B(OH)2 (1
b
equiv). Yields determined by GC using dodecane as the internal
c
standard. Isolated yield after column chromatography on silica gel.
d
Complete conversion of the boronic acid was observed due to the
formation of C6F3H3 as a side product.
We decided to gain further insight in these transformations
through DFT calculations. The transmetalations of 1 with both
phenyl- and (pentafluorophenyl)boronic acid, are exothermic
processes, as shown in Figure 2. A direct transmetalation
Finally, we decided to explore the effect of the ancillary
ligand on gold in this transmetalation reaction. For this purpose
we selected cis-dichloro(pentafluorophenyl)(tri-tert-
butylphosphine)gold(III) (7)20b and trans-dichloro[N,N-bis-
(2,6-diisopropylphenyl)imidazol-2-yl](pentafluorophenyl)gold-
(III) (8)20b (Scheme 3). We first tested their reactivity in the
Scheme 3
Figure 2. Computational study on the transmetalation of 1. Activation
energies are given in kcal/mol.
presence of phenylboronic acid. As in the previous cases, only
unreacted starting material was observed in the case of complex
8. In contrast, the reaction of 7 delivered, after only 1 h,
pentafluorochlorobenzene and [(tPBu3)AuICl] as a result of the
reductive elimination in the starting gold complex under the
reaction conditions (eq 4). The reaction of 7 with C6F5B(OH)2
afforded an outcome similar to that shown in eq 4, which
emphasized the greater ability of this complex to undergo
reductive elimination prior to transmetalation with the
electron-deficient boron species.25 The reaction of 8 with
C6F5B(OH)2 returned the starting complex unreacted, thus
showcasing that the bulkiness of the NHC ligand blocks the
involving the exchange of the chloride ligand from Au(III) to
the boron atom and aryl transfer from boron onto the metal
center was studied. As shown in Figure 2, this mechanism
appears to be highly unlikely. Not only are the activation
energies for the corresponding transition states I and II
abnormally high19b (>50 kcal/mol) but also the reactivity trend
is against the experimental observations (57.8 kcal/mol for
transmetalation of 1 with C6F5B(OH)2 vs 54.1 kcal/mol for the
analogous transmetalation with C6H5B(OH)2). These results
are not surprising as, in a classical transmetalation mechanism,
the organic fragment on the boron reagent plays a role as
nucleophile when being transferred to the metal center. Thus,
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Communication
the presence of five fluorine atoms on the benzene ring would
strongly compromise the nucleophilic character of the organic
ligand to be transferred.
dinates. This material is available free of charge via the Internet
at http://pubs.acs.org.
A different mechanism in which the electrophilicity, rather
than the nucleophilicity, on boron plays a key role must thus
govern these transformations. The electrophilicity values (ω)
obtained from the HOMO and LUMO energies on the boron
reagents show that (pentafluorophenyl)boronic acid is a better
electrophile (1.58 eV) in comparison to phenylboronic acid
(1.10 eV).26 Thus, an explanation of the higher reactivity
observed for electron-deficient boronic acids could stem from a
stepwise mechanism in which the first, rate-determining step
involves the activation of the gold by abstraction of a chloride
ligand by the electrophilic boron, which would thus act as a
Lewis acid. This possibility seems to be plausible on the basis of
the equilibrium shown in Figure 3. Although it is well
AUTHOR INFORMATION
■
Corresponding Author
*E-mail for C.N.: cristina.nevado@chem.uzh.ch.
Notes
The authors declare no competing financial interest.
Biography
́
Cristina Nevado graduated in chemistry at the Autonoma University of
Madrid in 2000. In October 2004 she received her Ph.D. in organic
chemistry from the same university, working with Prof. Antonio M.
Echavarren in late-transition-metal-catalyzed reactions. After a
postdoctoral stay in the group of Prof. Alois Furstner at the Max-
̈
Planck-Institut fur Kohlenforschung (Germany), she joined the
̈
University of Zurich as an Assistant Professor in May 2007. In 2011,
̈
Cristina was awarded the Chemical Society Reviews Emerging
Investigator Award and the Thieme Chemistry Journal Award in
recognition of her contributions in the field of synthetic organic
chemistry. In 2012 she received an ERC Junior Investigator grant and
has been awarded the Werner Prize of the Swiss Chemical Society. In
2013 she became Full Professor at the Organic Chemistry Institute of
Figure 3. Electrophilic mechanism for Au(III)−B transmetalation.
the University of Zurich. Rooted in the wide area of organic chemistry,
her research program is focused on complex chemical synthesis and
new organometallic reactions.
̈
recognized that the electrophilicity of boron, and thus its
ability to accept anions such as chloride, is reduced in the
presence of donating (hydroxy or alkoxy) substituents, the
corresponding B−Cl-bonded complexes could be localized as
zwitterionic intermediates III and IV. Upon chloride
abstraction, the OH groups on the boronic acid coordinate to
gold to stabilize the electrophilic metal center. The energy
values show that the formation of the B−Cl bond is favored by
1.6 kcal/mol in the perfluorinated reagent in comparison to
that in the phenylboronic acid. It is thus reasonable to propose
that intermediates of type III precede the migration of the aryl
ligand from boron to gold, although the exact nature of this
process or alternative reaction mechanisms cannot be
conclusively proposed at this stage.27
We report here the first examples of direct gold−boron
transmetalation for aryl gold(III) dichlorides, which have been
proposed as likely intermediates in gold(I)/gold(III) catalytic
cycles.19j−l Discrete arene−gold(III) complexes transmetalate
with electron-deficient boronic acids in the absence of base to
give the corresponding diaryl−gold(III) complexes. Unlike
gold(III) hydroxo complexes, under our conditions gold(III)
chloride complexes proved unfortunately unreactive toward
electron-rich boronic acids.
ACKNOWLEDGMENTS
■
The European Research Council (ERC Starting grant agree-
ment no. 307948) and the Organic Chemistry Institute of the
University of Zurich are kindly acknowledged for financial
support. Prof. Anthony Linden is kindly acknowledged for the
X-ray crystal structure determinations and the SGI/IZO-SGIker
UPV/EHU and Schrodinger (UZH) for allocation of computa-
̈
tional resources.
REFERENCES
■
(1) Lennox, A. J. J.; Lloyd-Jones, G. C. Angew. Chem., Int. Ed. 2013,
52, 7362−7370.
(2) (a) Miyaura, N.; Yamada, K.; Suginome, H.; Suzuki, A. J. Am.
Chem. Soc. 1985, 107, 972−980. (b) Suzuki, A. J. Organomet. Chem.
1999, 576, 147−168. (c) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95,
2457−2483.
(3) (a) Miyaura, N.; Yamada, K.; Suzuki, A. Tetrahedron Lett. 1979,
20, 3437−3440. (b) Miyaura, N.; Suzuki, A. J. Chem. Soc., Chem.
Commun. 1979, 866−867. (c) Braga, A. A. C.; Morgon, N. H.; Ujaque,
G.; Maseras, F. J. Am. Chem. Soc. 2005, 127, 9298−9307. (d) Braga, A.
A. C.; Morgon, N. H.; Ujaque, G.; Lledos, A.; Maseras, F. J. Organomet.
Chem. 2006, 691, 4459−4466. (e) Braga, A. A. C.; Ujaque, G.;
Maseras, F. Organometallics 2006, 25, 3647−3658.
ASSOCIATED CONTENT
* Supporting Information
Text, figures, tables, and CIF files giving synthetic and
■
S
(4) Amatore, C.; Jutand, A.; Le Duc, G. Chem. Eur. J. 2011, 17,
2492−2503.
computational details, crystallographic data, and XYZ coor-
1331
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Organometallics
Communication
(5) Carrow, B. P.; Hartwig, J. F. J. Am. Chem. Soc. 2011, 133, 2116−
2119.
(6) Schmidt, A. F.; Kurokhtina, A. A.; Larina, E. V. Russ. J. Gen. Chem.
Flower, K. R.; Pritchard, R. G.; Brisdon, A. K.; Quayle, P. Dalton Trans.
2011, 40, 11696−11697.
(20) (a) Hofer, M.; Nevado, C. Eur. J. Inorg. Chem. 2012, 9, 1338−
1341. (b) Hofer, M.; Nevado, C. Tetrahedron 2013, 69, 5751−5757.
(c) Gaillard, S.; Slawin, A. M. Z.; Bonura, A. T.; Stevens, E. D.; Nolan,
2011, 81, 1573−1574.
(7) Amatore, C.; Jutand, A.; Le Duc, G. Chem. Eur. J. 2012, 18,
6616−6625.
S. P. Organometallics 2010, 29, 394−402. (d) Pazicky, M.; Loos, A.;
̌
́
Ferreira, M. J.; Serra, D.; Vinokurov, N.; Rominger, F.; Jakel, C.;
̈
(8) Lennox, A. J. J.; Lloyd-Jones, G. C. J. Am. Chem. Soc. 2012, 134,
7431−7441.
Hashmi, A. S. K.; Limbach, M. Organometallics 2010, 29, 4448−4458.
(21) Uson, R.; Laguna, A.; Pardo, J. Synth. React. Inorg. Met.-Org.
Chem. 1974, 4, 499−513.
(9) (a) Dick, G. R.; Woerly, E. M.; Burke, M. D. Angew. Chem., Int.
Ed. 2012, 51, 2667−2672. (b) Molander, G. A.; Wisniewski, S. R. J.
Am. Chem. Soc. 2012, 134, 16856−16868.
(22) Upon heating to 150 °C, the decomposition of (pentafluor-
ophenyl)boronic acid to pentafluorobenzene was clearly observed.
Thus, we favor the idea of a protodeborylation to explain the
formation of pentafluorobenzene in the reaction mixture in
comparison to protodeauration, as no significant amount of C6F5H
was observed from 1 (see Scheme 2, eq 1) under similar conditions.
(23) For reductive elimination on gold(III) bis-aryl species, see:
(a) Wolf, W. J.; Winston, M. S.; Toste, F. D. Nat. Chem. 2014, 6, 159−
164 For previous studies on gold(III) bis-alkyl species, see:.
(b) Komiya, S.; Kochi, J. K. J. Am. Chem. Soc. 1976, 98, 7599−7609.
(c) Komiya, S.; Albright, T. A.; Hoffmann, R.; Kochi, J. K. J. Am. Chem.
Soc. 1976, 98, 7255−7265. (d) Hashmi, A. S. K.; Blanco, M. C.;
Fischer, D.; Bats, J. W. Eur. J. Org. Chem. 2006, 1387−1389.
(e) Ghidiu, M. J.; Pistner, A. J.; Yap, G. P. A.; Lutterman, D. A.;
Rosenthal, J. Organometallics 2013, 32, 5016−5029. For studies on
reductive elimination for other transition metals, see: (f) Roy, A. H.;
Hartwig, J. J. Am. Chem. Soc. 2001, 123, 1232−1233.
(24) CCDC 952781 (4) contains supplementary crystallographic
data for this paper. Crystallographic data for 1, cis-2, 7, and 8 have
been previously reported. See ref 20a and also CCDC 843007 and
842899 for 1 and cis-2, respectively. See ref 20b and CCDC-920666
and CCDC-921424 for 7 and 8, respectively. These data can be
obtained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
(25) C6F5H stemming from competitive protodeuration and/or
protodeborylation process was also detected.
(26) (a) Parr, R. G.; von Szentpaly, L.; Liu, S. J. Am. Chem. Soc. 1999,
121, 1922−1924. (b) Gomez-Bengoa, E.; Helm, M. D.; Plant, A.;
Harrity, J. P. A. J. Am. Chem. Soc. 2007, 129, 2691−2699.
(27) The reactions summarized in Scheme 2, eqs 2 and 3, were
repeated in the presence of BHT without significant variation in the
reaction outcome. Reactions in the presence in TEMPO showed a
decreased efficiency, since both the boronic acid and the starting gold
complex 1 undergo decomposition upon stirring in the presence of
TEMPO at high temperatures.
(10) (a) Furstner, A.; Davies, P. W. Angew. Chem., Int. Ed. 2007, 46,
̈
3410−3449. (b) Gorin, D. J.; Toste, F. D. Nature 2007, 446, 395−403.
(c) Hashmi, A. S. K. Angew. Chem., Int. Ed. 2010, 49, 5232−5341.
́
(d) Jimenez Nunez, E.; Echavarren, A. M. Chem. Rev. 2008, 108,
̃
3326−3350.
(11) (a) Wegner, H. A. Angew. Chem., Int. Ed. 2011, 50, 8236−8247.
(b) Garcia, P.; Malacria, M.; Auber, C.; Gandon, V.; Fensterbank, L.
ChemCatChem 2010, 2, 493−497. (c) Hopkinson, M. N.; Gee, A. D.;
Gouverneur, V. Chem. Eur. J. 2011, 17, 8248−8262. (d) de Haro, T.;
Nevado, C. Synthesis 2011, 16, 2530−2539.
(12) (a) Matteson, D. S.; Allies, P. G. J. Organomet. Chem. 1973, 54,
35−50. (b) Brown, H. C.; Snyder, C. H. J. Am. Chem. Soc. 1961, 83,
1002−1003. (c) Yamamoto, Y.; Yatagai, H.; Moritani, I. J. Am. Chem.
Soc. 1975, 97, 5606−5607. (d) Ye, H.; Lu, Z.; You, D.; Chen, Z.; Li, Z.
H.; Wang, H. Angew. Chem., Int. Ed. 2012, 51, 12047−12050.
(13) (a) Sladek, A.; Hofreiter, S.; Paul, M.; Schmidbaur, H. J.
Organomet. Chem. 1995, 501, 47−51. (b) Forward, J. M.; Fackler, J. P.;
Staples, R. J. Organometallics 1995, 14, 4194−4198.
(14) Partyka, D. V.; Zeller, M.; Hunter, A. D.; Gray, T. G. Angew.
Chem., Int. Ed. 2006, 45, 8188−8191. (b) Partyka, D. V.; Zeller, M.;
Hunter, A. D.; Gray, T. G. Inorg. Chem. 2012, 51, 8394−8401.
(15) Hashmi, A. S. K.; Ramamurthi, T. D.; Rominger, F. J.
Organomet. Chem. 2009, 592−597.
(16) Dupuy, S.; Crawford, L.; Buhl, M.; Slawin, A. M. Z.; Nolan, S. P.
Adv. Synth. Catal. 2012, 354, 2380−2386.
(17) (a) Zhang, G.; Peng, Y.; Cui, L.; Zhang, L. Angew. Chem., Int. Ed.
2009, 48, 3112−3115. (b) For an example of heterogeneous catalysis,
see: Carrettin, S.; Guzman, J.; Corma, A. Angew. Chem., Int. Ed. 2005,
44, 2242−2245. (c) Ball, L. T.; Green, M.; Lloyd-Jones, G. C.; Russell,
A. Org. Lett. 2010, 12, 4724−4727. (c) Brenzovich, W. E., Jr.; Brazeau,
J. F.; Toste, F. D. Org. Lett. 2010, 12, 4728−4731. For the first
example of F+-donor-induced C−C bond formation from organo-
gold(I) complexes, see ref 15 and also: (d) Hashmi, A. S. K.;
Ramamurthi, T. D.; Todd, M. H.; Tsang, A. S.-K.; Graf, K. Aust. J.
Chem. 2010, 63, 1619−1626.
NOTE ADDED AFTER ASAP PUBLICATION
■
(18) Zhang, G.; Cui, L.; Wang, Y.; Zhang, L. J. Am. Chem. Soc. 2010,
132, 1474−1475.
In the version of this paper that was published on February 5,
2014, there was an inadvertent omission of a relevant precedent
by Bochmann and co-workers describing examples of trans-
metalation of gold(III) hydroxide with boronic acids. In the
version of this paper that appears as of February 19, 2014, the
appropriate references have been added as refs 19j−l. In
addition, we now cite this previous work in the main text and in
our conclusions at the end of the paper. We apologize for this
unintentional omission.
(19) (a) Brenzovich, W. E.; Benitez, D.; Lackner, A. D.; Shunatona,
H. P.; Tkatchouk, E.; Goddard, W. A.; Toste, F. D. Angew. Chem., Int.
Ed. 2010, 49, 5519−5522. (b) Tkatchouk, E.; Mankad, N. P.; Benitez,
D.; Goddard, W. A.; Toste, F. D. J. Am. Chem. Soc. 2011, 133, 14293−
14300. (c) Faza, O. N.; Lopez, C. S. J. Org. Chem. 2013, 78, 4929−
4939. (d) Melhado, A. D.; Brenzovich, W. E., Jr.; Lackner, A. D.;
Toste, F. D. J. Am. Chem. Soc. 2010, 132, 8885−8887. (e) Mankad, N.
P.; Toste, F. D. J. Am. Chem. Soc. 2010, 132, 12859−12861. For
studies on Au(I)/Pd(II) transmetalation, see: (f) Hashmi, A. K. S.;
Lothschutz, C.; Dopp, R.; Rudolph, M.; Ramamurthi, T. D.;
Rominger, F. Angew. Chem., Int. Ed. 2009, 48, 8243−8246. (g) Roth,
́
K. E.; Blum, S. A. Organometallics 2011, 30, 4811−4813. (h) Perez-
Temprano, M.; Casares, J. A.; de Lera, A. R.; Alvarez, R.; Espinet, P.
Angew. Chem., Int. Ed. 2012, 51, 4917−4920. (i) Hansmann, M. M.;
Pernpointner, M.; Dopp, R.; Hashmi, A. K. S. Chem. Eur. J. 2013, 45,
̈
15290−15303. For previous studies on the transmetalation of κ3-
(C∧N∧C)*Au(OX) with both electron-deficient and electron-rich
boronic acids, see: (j) Rosca
Chem. Commun. 2012, 48, 7247−7249. (k) Smith, D. A.; Rosca
Bochmann, M. Organometallics 2012, 31, 5998−6000. (l) Price, G. A.;
̧
, D.-A.; Smith, D. A.; Bochmann, M.
̧
, D.-A.;
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