C,O-Chelated BINOL/Gold(III) Complexes: Synthesis and Catalysis with Tunable Product Profiles

Article abstract of DOI:10.1002/anie.201612243

Unprecedented stable BINOL/gold(III) complexes, adopting a novel C,O-chelation mode, were synthesized by a modular approach through combination of 1,1′-binaphthalene-2,2′-diols (BINOLs) and cyclometalated gold(III) dichloride complexes [(C^N)AuCl₂]. X-ray crystallographic analysis revealed that the bidentate BINOL ligands tautomerized and bonded to the Au^III atom through C,O-chelation to form a five-membered ring instead of the conventional O,O′-chelation giving a seven-membered ring. These gold(III) complexes catalyzed acetalization/cycloisomerization and carboalkoxylation of ortho-alkynylbenzaldehydes with trialkyl orthoformates.

Full text of DOI:10.1002/anie.201612243

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201612243
German Edition: DOI: 10.1002/ange.201612243
Ligand Effects
C,O-Chelated BINOL/Gold(III) Complexes: Synthesis and Catalysis
with Tunable Product Profiles
Jian-Fang Cui, Hok-Ming Ko, Ka-Pan Shing, Jie-Ren Deng, Nathanael Chun-Him Lai, and
Man-Kin Wong*
Abstract: Unprecedented stable BINOL/gold(III) complexes,
adopting a novel C,O-chelation mode, were synthesized by
a modular approach through combination of 1,1’-binaphtha-
lene-2,2’-diols (BINOLs) and cyclometalated gold(III)
dichloride complexes [(C^N)AuCl2]. X-ray crystallographic
analysis revealed that the bidentate BINOL ligands tautomer-
ized and bonded to the AuIII atom through C,O-chelation to
form a five-membered ring instead of the conventional O,O’-
chelation giving a seven-membered ring. These gold(III)
complexes catalyzed acetalization/cycloisomerization and car-
boalkoxylation of ortho-alkynylbenzaldehydes with trialkyl
orthoformates.
electron-deficient nitrogen-containing compounds, such as
pyridines,[3a,b,f] Schiff bases,[3c] N-heterocyclic carbenes,[5] and
triazole derivatives,[3g,h] have been used as ligands for gold-
(III) complexes (Figure 1a). In principle, the stability of
gold(III) ions significantly increases upon complexation with
G
old catalysis has contributed to a diversity of novel organic
transformation reactions streamlining organic synthesis with
excellent atom economy and operational simplicity owing to
its superior reactivity, excellent selectivity, and high func-
tional-group tolerance.[1] Meticulous choice of ligand in gold
catalysis is of significance to prevent the decomposition of
simple gold salts in catalytic cycles and fine-tune the catalytic
activity and product enantioselectivity.[1i,2] In particular,
a variety of phosphine/gold(I) and N-heterocyclic carbene/
gold(I) complexes have been developed as efficient catalysts
for novel synthetic transformations. However, gold(I) com-
plexes have two coordination sites with a linear geometry,
thus leading to a challenge when arranging ligands around the
gold(I) center for tuning catalytic activity and introducing
a chiral environment.[1e,i,2a]
Figure 1. a) Gold(III) complexes previously reported by other research
groups and our group. b) Synthesis of unprecedented stable BINOL/
gold(III) complexes adopting a novel C,O-chelation mode.
ligands. However, stable gold(III) complexes generally
exhibit poor catalytic activity. Thus, a significant challenge
in the successful development of gold(III) complexes as
efficient catalysts is to strike a balance between stability and
catalytic activity.[5,6]
Over the years, we have been developing gold(III)
complexes, including Salen-based gold(III) complexes[7] and
cyclometalated gold(III) dichloride complexes [(C^N)AuCl2,
C^N = 2-arylpyridyl],[8] as efficient catalysts for organic syn-
thesis. In addition, we reported that the bis(cyclometalated)
gold(III) complex [(C^N)2AuBF4] is able to enhance the
stability of the AuIII cation with good catalytic activity.[6] To
further explore the potential of gold(III) catalysis, it is
important to develop easily assessable, stable, and tunable
gold(III) complexes.
1,1’-Binaphthalene-2,2’-diols (BINOLs), which are readily
bound to transition metals through both oxygen atoms to
form a seven-membered ring,[9] are privileged ligands in
asymmetric transition-metal catalysis.[10] The reported stabi-
lization of cationic gold(III) complexes by catechol deriva-
tives inspired us to examine BINOLs as the supporting
ligands.[11] The two consecutive O-anionic centers on the
BINOL ligands were able to donate sufficient electron
density to stabilize a highly electrophilic AuIII center. How-
ever, such phenolate ligands are strong reductants, and even
the preparation of gold(I) phenolate complexes was highly
challenging and the compounds were very sensitive.[12] To
Gold(III) complexes have a square-planar geometry with
four coordination sites, thus allowing easy fine-tuning through
diverse ligand design in a modular approach. However, the
development of gold(III) complexes for catalysis remains
largely unexplored because of difficult access to the high
oxidation state under mild reaction conditions and a lack of
suitable non-redox ligands.[3] The great challenge in synthesiz-
ing stable gold(III) complexes comes from the facile reduc-
tion of gold(III) complexes to either gold(I) or gold(0)
species.[4] For example, electron-rich tertiary phosphine and
amine ligands[3h] are not compatible with the gold(III) ion
owing to the possible gold(III) reduction. Thus, neutral or
[*] Dr. J.-F. Cui, H.-M. Ko, K.-P. Shing, J.-R. Deng, N. C.-H. Lai,
Dr. M.-K. Wong
State Key Laboratory of Chirosciences
Department of Applied Biology and Chemical Technology
The Hong Kong Polytechnic University, Hong Kong (China)
E-mail: mankin.wong@polyu.edu.hk
Supporting information for this article can be found under:
http://dx.doi.org/10.1002/anie.201612243.
Angew. Chem. Int. Ed. 2017, 56, 1 – 7
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1
These are not the final page numbers!

Angewandte
Communications
Chemie
fully utilize the four coordination sites of gold(III) complexes,
we hypothesized that incorporating a BINOL ligand into
a cyclometalated AuIII dichloride complex [(C^N)AuCl2] by
O,O’-chelation with the AuIII center by replacing the two
chloride atoms would give a stable, neutral, and tetracoordi-
nated gold(III) complex while maintaining tunable catalytic
activity in organic synthesis. To our surprise, unprecedented
gold(III) complexes in which the BINOL moiety adopted an
unusual C,O-chelation mode with the AuIII center were
obtained instead of the expected O,O’-chelation (Figure 1b).
Initially, an oxazoline-based gold(III) dichloride complex
(S1) was prepared by a literature method.[13] Treatment of S1
with commercially available (S)-BINOL in the presence of
Cs2CO3 in methanol at room temperature afforded an orange-
red solid [(R)-1] in 85% yield (Scheme 1a), and it was
afforded the gold(III) complex (R)-1 with the quaternary
stereogenic carbon center in the R configuration. Moreover,
S1 reacted with (R)-BINOL under the same reaction
conditions to afford the enantiomer, (S)-1, in 88% yield,
which was also well-characterized by 1H NMR and 13C NMR
spectroscopy, high-resolution ESI-MS, and X-ray crystallo-
graphic analysis (Scheme 1b). Circular dichroism (CD)
indicated the stereochemical properties of the enantiomers
(R)-1 and (S)-1 (Scheme 1c).
A search of the literature revealed that this kind of
peculiar C,O-chelation mode for BINOL derivatives with PdII
and PtII have rarely been reported.[16] To our knowledge, we
are the first to synthesize chiral BINOL–oxazoline hybrid
gold(III) complexes [(R)-1 and (S)-1] with an unusual C,O-
chelation mode. The possible reasons for (R)-1 and (S)-
1 accommodating the peculiar C,O binding mode would be
enol–keto tautomerization of BINOL in the presence of
Cs2CO3 and the higher tendency of the gold center to
coordinate the carbanion rather than phenoxide.[16] This
unprecedented C,O-chelation, rather than O,O’-chelation
mode, of BINOL towards the AuIII center of the complex
[Au(CN)Cl2] represents a facile approach for generating
À
À
strong Au C and Au O bonds, thus paving the way to stable
gold(III) complexes. In this work, we are the first to develop
a modular approach for synthesizing a series of novel chiral
C,O-chelated BINOL–gold(III) complexes by a combination
of diverse chiral (S)-BINOL and (R)-BINOL derivatives with
various oxazoline- and pyridine-based cyclometalated gold-
(III) complexes.
The scope of using various oxazoline- and pyridine-based
cyclometalated gold(III) dichloride complexes [(C^N)AuCl2]
for synthesizing chiral C,O-chelated BINOL–gold(III) com-
plexes were studied (Table 1). Chiral oxazoline-based gold-
(III) dichloride complexes (S2–S4) were prepared by a liter-
ature method with modifications (see Schemes S2 and S3 in
the Supporting Information).[13a,17] Treatment of (S)-BINOL
and (R)-BINOL with these chiral oxazoline-based gold(III)
dichloride complexes under the optimized reaction condi-
tions, respectively, gave the four stereoisomers of a chiral
BINOL-oxazoline hybrid cyclometalated gold(III) complex
(2–4; with R,S-, R,R-, S,S-, and S,R-configurations, respec-
tively) in 87–96% yield. Reactions of (S)-BINOL and (R)-
BINOL with the ortho-substituted pyridine-based complexes
S5–S11, respectively, afforded chiral gold(III) complexes 5–11
with R- and S-configurations in 80–95% yield.
Scheme 1. a) Formation of the stable gold(III) complex (R)-1 derived
from (S)-BINOL and cyclometalated gold(III) dichloride S1 in an
unusual C,O-chelation manner, and the X-ray crystal structure of (R)-1.
Thermal ellipsoids are shown at 50% probability. b) Formation of the
stable gold(III) complex (S)-1, and the X-ray crystal structure of (S)-1.
Thermal ellipsoids are shown at 50% probability. c) Circular dichroism
(CD) spectrum of (R)-1 and (S)-1, 0.1 mgmLÀ1 in CHCl3.
1
characterized by H NMR and 13C NMR spectroscopy, and
high-resolution ESI-MS. However, the unsymmetrical proton
signal in the 1H NMR spectra and the carbonyl signal (d
ꢀ 200 ppm) appearing in the 13C NMR spectra indicated
that the structure of this gold(III) complex is not the proposed
O,O’-chelated gold(III) complex. Notably, X-ray crystallo-
graphic analysis revealed that the structure of (R)-1,[14] in
which the BINOL moiety adopted an unprecedented C,O-
chelation mode with the AuIII center (Scheme 1a).[15] The
O,O’-bidentate (S)-BINOL ligand tautomerized and bonded
to the Au atom by C,O-chelation to form a five-membered
ring instead of O,O’-chelation giving a seven-membered ring.
The crystal structure reveals that the gold(III) atom in (R)-
1 adopts a square-planar geometry surrounded by cis-oxygen-
nitrogen and cis-carbon-carbon atoms. The complex (R)-
1 was light, air, and moisture insensitive and could be isolated
and stored at ambient conditions. It is stable upon exposure to
air for months. Remarkably, an axial-to-central chirality
transfer occurred during the complex formation between
(S)-BINOL and [(C^N)AuCl2]. The (S)-BINOL exclusively
As literature reported that the coordination mode of PdII
and PtII with BINOL and VANOL exclusively adopted the
O,O’-chelation, while the apparently more bulky ligands 3,3’-
Me2BINOL and VAPOL preferred the C,O-chelation.[16d] We
proceeded to employ 3,3’-disubstituted BINOLs for the
formation of the C,O-chelated BINOL–gold(III) complexes
(Table 2). (S)-3,3’-Me2BINOL and (R)-3,3’-Me2BINOL were
used to react with the oxazoline-based cyclometalated gold-
(III) dichloride S1, thus giving the C,O-chelation products
(R)-12 and (S)-12 in 77 and 83% yield, respectively. Similarly,
reaction of (S)-6,6’-dibromo-BINOL and (R)-6,6’-dibromo-
BINOL with S1 afforded (R)-13 and (S)-13, respectively, in
excellent yield (93 and 89%). Next, the scope of various
sterically bulky 3,3’-disubstituted BINOLs were investigated.
2
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 7
These are not the final page numbers!

Angewandte
Communications
Chemie
Table 1: Scope of using oxazoline- and pyridine-based cyclometalated
Table 2: Scope of using chiral 3,3’-disubstituted BINOL ligands for the
gold(III) dichloride complexes for the synthesis of 1–11.[a,b]
synthesis of 12–22.[a,b]
[a] Reaction conditions: gold(III) dichloride complex (0.2 mmol), (S)-
BINOL or (R)-BINOL (1.1 equiv), Cs2CO3 (2.2 equiv), methanol (10 mL),
room temperature, reaction time: 1 h. [b] Yield of isolated product.
[c] Configuration validated by X-ray crystallographic analysis.
BINOLs with SiPh3, Br, and aryl groups on 3,3’-positions were
well-compatible with S1 to form the cyclometalated gold(III)
complexes 14–21 (72–92% yield) with the C,O-chelation.
Furthermore, (S)-3,3’-Me2BINOL and (R)-3,3’-Me2BINOL
reacted with the chiral oxazoline-based gold(III) dichloride
complexes (S)-S3 and (R)-S3, respectively, and afforded the
four stereoisomers (R,S)-22, (R,R)-22, (S,S)-22, and (S,R)-22
in yields ranging from 64 to 79%.
The axial-to-central chirality transfer from the chiral
BINOL to the resulting gold(III) complexes was again
confirmed by X-ray crystallographic analysis (Figure 2).[14]
Reaction of (S)-BINOL with (S)-S4, and reaction of with
(R)-BINOL with (R)-S4 afforded the corresponding (R,S)-4
and (S,R)-4, thus indicating that the axial chirality on the
chiral BINOL exclusively transferred to the resulting opti-
cally pure gold(III) complexes. This kind of efficient axial-to-
central chirality transfer was also applicable to the synthesis
of (R,S)-22 and (S,S)-22.
[a] Reaction conditions: gold(III) dichloride complex (0.1 mmol), (S)-
3,3’-disubstituted BINOL or (R)-3,3’-disubstituted BINOL (1.1 equiv),
Cs2CO3 (2.2 equiv), methanol (5 mL), room temperature, reaction time:
1 h. [b] Yield of isolated product. [c] 0.05 mmol. [d] 24 h. [e] Configura-
tion validated by X-ray crystallographic analysis.
Reaction of rac-BINOL with the chiral oxazoline-based
gold(III) dichloride complex (S)-S4 was conducted under the
standard reaction conditions. Diastereoisomers (R,S)-4 and
(S,S)-4 were well-separated by column chromatography on
silica gel in 46 and 44% yield, respectively (Scheme 2a).
These results indicated that chiral BINOL–gold(III) com-
plexes could be synthesized from chiral oxazoline-based
gold(III) dichloride complexes and inexpensive racemic
BINOL. A gram-scale reaction of rac-BINOL with S1 was
conducted (Scheme 2b). rac-BINOL (1.58 g, 5.5 mmol)
reacted with S1 (2.21 g, 5.0 mmol) in the presence of
Cs2CO3 in methanol at room temperature for 1 hour to
afford rac-1 in 95% yield (3.10 g).
Figure 2. X-ray crystal structures of a) (R,S)-4, b) (S,R)-4, c) (R,S)-22,
and d) (S,S)-22. Displacement ellipsoids are drawn at the 50%
probability level. Solvent molecules are omitted for clarity.
With rac-1 in hand, we proceeded to examine the catalytic
activity of the newly developed C,O-chelated BINOL/gold-
Angew. Chem. Int. Ed. 2017, 56, 1 – 7
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
3
These are not the final page numbers!

Angewandte
Communications
Chemie
used. We found that using 2.5 mol% rac-1, 20 mol% cam-
phorsulfonic acid, and 6.0 equivalents of CH(OEt)3 in DCE
gave the best yield (87%).
With the optimized reaction conditions, we investigated
the scope of this gold(III)-catalyzed carboalkoxylation reac-
tion of ortho-ethynylbenzaldehydes (Table 4). Using tri-
methyl orthoformate, the corresponding indanone 24b was
obtainied with lower yield (56%). Yet, no carboalkoxylation
Table 4: Carboalkoxylation of ortho-alkynylbenzaldehydes with trialkyl
orthoformates catalyzed by rac-1.[a,b]
Scheme 2. a) Access to the chiral diastereoisomers (R,S)-4 and (S,S)-4
from reaction of rac-BINOL and (S)-S4. b) A gram-scale synthesis rac-
1 from rac-BINOL and S1.
(III) complexes in organic transformations of ortho-alkynyl-
benzaldehydes.[18] Treatment of various ortho-alkynylbenzal-
dehydes with trialkyl orthoformates in the presence of
2.5 mol% of rac-1 gave the six-membered acetal products
23a–k in 62–96% yield without the five-membered counter-
part as reported in literature[18d] (Table 3). These findings
[a] Reaction conditions: ortho-ethynylbenzaldehyde (0.5 mmol), CH-
(OR3)3 (3.0 mmol, 6.0 equiv), d-(+)-10-Camphorsulfonic acid
(20 mmol%), DCE (3.0 mL), room temperature, 24 h. [b] Yield of
isolated product. [c] 8 h. [d] At 608C. DCE=dichloroethane.
Table 3: Gold(III) complex rac-1 catalyzed tandem acetalization/cyclo-
isomerization of ortho-alkynylbenzaldehydes with trialkyl orthoformate-
s.[a,b]
product was found when triisopropyl orthoformate was used.
Substrates with electron-withdrawing groups (Cl, F), elec-
tron-donating groups (OMe), as well as two substituents on
the aryl ring were well-tolerated (products 24d–i in 61–74%
yield). The reaction of an ethynyl-substituted substrate
proceeded smoothly under the standard reaction conditions,
thus giving the corresponding indanone 24ja in 57% yield
together with 24jb (hydration product of 24ja) in 26% yield.
As shown in Table 3, reaction of ortho-alkynylbenzalde-
hydes with trialkyl orthoformates catalyzed by rac-1 gave six-
membered acetal products (23). In contrast, addition of
camphorsulfonic acid led instead to the carboalkoxylation
products 24 (Table 4). One possibility might be the acid-
promoted formation of acetals from 2-alkynylbenzaldehydes
and subsequent carboalkoxylation reaction[19] to give 24
(mechanistic studies of these reaction pathways are ongoing
in our laboratory).
In this work, the new approach of synthesizing novel C,O-
chelated BINOL–gold(III) complexes has opened up a new
research direction for gold catalysis based on high-valent
gold(III) chemistry. It is envisioned that further development
of gold(III) catalysis will lead to the discovery of novel
organic transformation reactions which would have signifi-
cantly different reactivity, selectivity, and substrate scope
compared with gold(I) catalysis. Moreover, it is worth
exploring the unique chiral environment around the AuIII
center in asymmetric catalysis. Our preliminary studies
showed that by using the chiral BINOL/gold(III) complex
(R,R)-2 (2.5 mol%) as a catalyst, carboalkoxylation of ortho-
alkynylbenzaldehyde with CH3OH gave 24b in 52% yield
with 41% ee (see Figure S1).
[a] Reaction conditions: ortho-alkynylbenzaldehyde (0.5 mmol), CH-
(OR3)3 (3.0 mmol, 6.0 equiv), DCE (3.0 mL), 508C, 12 h. [b] Yield of
isolated product. [c] At room temperature. [d] 8 h. [e] 24 h. DCE=di-
chloroethane.
showed that the catalysis of rac-1 towards tandem acetaliza-
tion/cycloisomerization of ortho-alkynylbenzaldehydes with
trialkyl orthoformates has excellent regioselectivity.
Interestingly, when sulfonic acid (20 mol%) was added to
the reaction mixture with 2.5 mol% rac-1, a carboalkoxylation
product (24a)[19] was exclusively formed in 87% yield, but the
tandem acetalization/cycloisomerization product 23b was not
obtained. The drastic change in product distribution indicated
that the product selectivity of rac-1 towards ortho-alkynyl-
benzaldehyde is adjusted by addition of acid. Encouraged by
these findings, we set out to optimize the reaction conditions
by screening various gold(I) and gold(III) catalysts, as well as
Brønsted acids, loading of catalysts and sulfonic acid, amount
of trimethyl orthoformate, as well as solvents (see Tables S1–
S4). As summarized in the Supporting Information, no
carboalkoxylation product was obtained when a simple gold-
(I) salt (AuCl), phosphine/gold(I) complexes (LAuCl; L =
PPh3 and JohnPhos), and mono- and bis(cyclometalated)
gold(III) complexes [(C^N)AuCl2 and (C^N)2AuBF4] were
4
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 7
These are not the final page numbers!

Angewandte
Communications
Chemie
Gonzµlez-Arellano, A. Corma, M. Iglesias, F. Sanchez, Chem.
Acknowledgments
Commun. 2005, 1990 – 1992; d) V. K.-Y. Lo, M.-K. Wong, C.-M.
Che, Org. Lett. 2008, 10, 517 – 519; e) H. Schmidbaur, A. Schier,
Arabian J. Sci. Eng. 2012, 37, 1187 – 1225; f) E. Langseth, C. H.
Gçrbitz, R. H. Heyn, M. Tilset, Organometallics 2012, 31, 6567 –
6571; g) Y. Yang, A. Qin, K. Zhao, D. Wang, X. Shi, Adv. Synth.
Catal. 2016, 358, 1433 – 1439; h) Y. Yang, W. Hu, X. Ye, D. Wang,
X. Shi, Adv. Synth. Catal. 2016, 358, 2583 – 2588; for pioneering
work on gold catalysis, gold(III) salts were often used: i) Y.
Fukuda, K. Utimoto, H. Nozaki, Heterocycles 1987, 25, 297 –
300; j) A. S. K. Hashmi, L. Schwarz, J.-H. Choi, T. M. Frost,
Angew. Chem. Int. Ed. 2000, 39, 2285 – 2288; Angew. Chem.
2000, 112, 2382 – 2385; k) A. S. K. Hashmi, T. M. Frost, J. W.
Bats, J. Am. Chem. Soc. 2000, 122, 11553 – 11554; l) A. S. K.
Hashmi, T. M. Frost, J. W. Bats, Org. Lett. 2001, 3, 3769 – 3771.
[4] a) A. S. K. Hashmi, M. C. Blanco, D. Fischer, J. W. Bats, Eur. J.
Org. Chem. 2006, 1387 – 1389; b) S. Gaillard, A. M. Z. Slawin,
A. T. Bonura, E. D. Stevens, S. P. Nolan, Organometallics 2010,
29, 394 – 402; c) A. Leyva-Pꢀrez, A. Corma, Angew. Chem. Int.
Ed. 2012, 51, 614 – 635; Angew. Chem. 2012, 124, 636 – 658.
[5] C.-Y. Wu, T. Horibe, C. B. Jacobsen, F. D. Toste, Nature 2015,
517, 449 – 454.
We are grateful for the financial support of Hong Kong
Research Grants Council (PolyU 153006/15P), State Key
Laboratory of Chirosciences, and Department of Applied
Biology and Chemical Technology. We thank Prof. Zhou
Zhongyuan for X-ray crystallographic analysis.
Conflict of interest
The authors declare no conflict of interest.
Keywords: chelates · gold · isomerization · ligand effects ·
structure elucidation
[1] a) A. S. K. Hashmi, Gold Bull. 2003, 36, 3 – 9; b) A. S. K.
Hashmi, Chem. Rev. 2007, 107, 3180 – 3211; c) E. Jimꢀnez-
NfflÇez, A. M. Echavarren, Chem. Rev. 2008, 108, 3326 – 3350;
d) A. Arcadi, Chem. Rev. 2008, 108, 3266 – 3325; e) D. J. Gorin,
B. D. Sherry, F. D. Toste, Chem. Rev. 2008, 108, 3351 – 3378; f) S.
Díez-Gonzµlez, N. Marion, S. P. Nolan, Chem. Rev. 2009, 109,
3612 – 3676; g) N. Krause, C. Winter, Chem. Rev. 2011, 111,
1994 – 2009; h) A. Corma, A. Leyva-Pꢀrez, M. J. Sabater, Chem.
Rev. 2011, 111, 1657 – 1712; i) Y.-M. Wang, A. D. Lackner, F. D.
Toste, Acc. Chem. Res. 2014, 47, 889 – 901; j) L. Zhang, Acc.
Chem. Res. 2014, 47, 877 – 888; k) R. Dorel, A. M. Echavarren,
Chem. Rev. 2015, 115, 9028 – 9072; l) W. Zi, F. D. Toste, Chem.
Soc. Rev. 2016, 45, 4567 – 4589; m) A. M. Asiri, A. S. K. Hashmi,
Chem. Soc. Rev. 2016, 45, 4471 – 4503; n) D. Pflästerer, A. S. K.
Hashmi, Chem. Soc. Rev. 2016, 45, 1331 – 1367.
[2] a) A. S. K. Hashmi, Nature 2007, 449, 292 – 293; b) M.-Z. Wang,
M.-K. Wong, C.-M. Che, Chem. Eur. J. 2008, 14, 8353 – 8364;
c) H. Duan, S. Sengupta, J. L. Petersen, N. G. Akhmedov, X. Shi,
J. Am. Chem. Soc. 2009, 131, 12100 – 12102; d) W. Wang, G. B.
Hammond, B. Xu, J. Am. Chem. Soc. 2012, 134, 5697 – 5705;
e) R. B. Dateer, B. S. Shaibu, R.-S. Liu, Angew. Chem. Int. Ed.
2012, 51, 113 – 117; Angew. Chem. 2012, 124, 117 – 121; f) P.
Nçsel, L. N. dos Santos Comprido, T. Lauterbach, M. Rudolph,
F. Rominger, A. S. K. Hashmi, J. Am. Chem. Soc. 2013, 135,
15662 – 15666; g) Z. Yu, B. Ma, M. Chen, H.-H. Wu, L. Liu, J.
Zhang, J. Am. Chem. Soc. 2014, 136, 6904 – 6907; h) Z.-M.
Zhang, P. Chen, W. Li, Y. Niu, X.-L. Zhao, J. Zhang, Angew.
Chem. Int. Ed. 2014, 53, 4350 – 4354; Angew. Chem. 2014, 126,
4439 – 4443; i) S. N. Karad, R.-S. Liu, Angew. Chem. Int. Ed.
2014, 53, 5444 – 5448; Angew. Chem. 2014, 126, 5548 – 5552; j) K.
Ji, Z. Zheng, Z. Wang, L. Zhang, Angew. Chem. Int. Ed. 2015, 54,
1245 – 1249; Angew. Chem. 2015, 127, 1261 – 1265; k) W. Zi, F. D.
Toste, Angew. Chem. Int. Ed. 2015, 54, 14447 – 14451; Angew.
Chem. 2015, 127, 14655 – 14659; l) H. Wu, W. Zi, G. Li, H. Lu,
F. D. Toste, Angew. Chem. Int. Ed. 2015, 54, 8529 – 8532; Angew.
Chem. 2015, 127, 8649 – 8652; m) S. E. Motika, Q. Wang, N. G.
Akhmedov, L. Wojtas, X. Shi, Angew. Chem. Int. Ed. 2016, 55,
11582 – 11586; Angew. Chem. 2016, 128, 11754 – 11758; n) L.
Huang, M. Rudolph, F. Rominger, A. S. K. Hashmi, Angew.
Chem. Int. Ed. 2016, 55, 4808 – 4813; Angew. Chem. 2016, 128,
4888 – 4893.
[6] H.-M. Ko, K. K.-Y. Kung, J.-F. Cui, M.-K. Wong, Chem.
Commun. 2013, 49, 8869 – 8871.
[7] V. K.-Y. Lo, Y. Liu, M.-K. Wong, C.-M. Che, Org. Lett. 2006, 8,
1529 – 1532.
[8] a) V. K.-Y. Lo, K. K.-Y. Kung, M.-K. Wong, C.-M. Che, J.
Organomet. Chem. 2009, 694, 583 – 591; b) K. K.-Y. Kung, G.-L.
Li, L. Zou, H.-C. Chong, Y.-C. Leung, K.-H. Wong, V. K.-Y. Lo,
C.-M. Che, M.-K. Wong, Org. Biomol. Chem. 2012, 10, 925 – 930;
c) K. K.-Y. Kung, V. K.-Y. Lo, H.-M. Ko, G.-L. Li, P.-Y. Chan, K.-
C. Leung, Z. Zhou, M.-Z. Wang, C.-M. Che, M.-K. Wong, Adv.
Synth. Catal. 2013, 355, 2055 – 2070.
[9] a) J. A. Heppert, S. D. Dietz, N. W. Eilerts, R. W. Henning, M. D.
Morton, F. Takusagawa, F. A. Kaul, Organometallics 1993, 12,
2565 – 2572; b) T. J. Boyle, N. W. Eilerts, J. A. Heppert, F.
Takusagawa, Organometallics 1994, 13, 2218 – 2229; c) K. M.
Totland, T. J. Boyd, G. G. Lavoie, W. M. Davis, R. R. Schrock,
Macromolecules 1996, 29, 6114 – 6125; d) M. Shibasaki, H. Sasai,
T. Arai, Angew. Chem. Int. Ed. Engl. 1997, 36, 1236 – 1256;
Angew. Chem. 1997, 109, 1290 – 1311; e) N. M. Brunkan, P. S.
White, M. R. Gagnꢀ, Angew. Chem. Int. Ed. 1998, 37, 1579 –
1582; Angew. Chem. 1998, 110, 1615 – 1618.
[10] a) Y. Chen, S. Yekta, A. K. Yudin, Chem. Rev. 2003, 103, 3155 –
3212; b) J. M. Brunel, Chem. Rev. 2005, 105, 857 – 898; c) J. M.
Brunel, Chem. Rev. 2007, 107, PR1 – PR45.
[11] C. H. A. Goss, W. Henderson, A. L. Wilkins, C. Evans, J.
Organomet. Chem. 2003, 679, 194 – 201.
[12] N. Ibrahim, M. H. Vilhelmsen, M. Pernpointner, F. Rominger,
A. S. K. Hashmi, Organometallics 2013, 32, 2576 – 2583.
[13] a) P. A. Bonnardel, R. V. Parish, R. G. Pritchard, J. Chem. Soc.
Dalton Trans. 1996, 3185 – 3193; b) P. A. Bonnardel, R. V. Parish,
J. Organomet. Chem. 1996, 515, 221 – 232.
[14] CCDC 1523053 [(R)-1], 1523052 [(S)-1], 1523064 [(R,S)-4],
1523057 [(S,R)-4], 1523060 [(R,S)-22], and 1523063 [(S,S)-22]
contain the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre.
[15] For the C-coordinated gold(I) complex, a crystal structure of
a gold(I) a-metalated ketone has been reported by Hashmi,
Laguna, and co-workers, see: A. S. K. Hashmi, S. Schäfer, M.
Wçlfle, C. Diez Gil, P. Fischer, A. Laguna, M. C. Blanco, M. C.
Gimeno, Angew. Chem. Int. Ed. 2007, 46, 6184 – 6187; Angew.
Chem. 2007, 119, 6297 – 6300.
[16] a) S. H. Bergens, P. H. Leung, B. Bosnich, A. L. Rheingold,
Organometallics 1990, 9, 2406 – 2408; b) N. M. Brunkan, P. S.
White, M. R. Gagnꢀ, J. Am. Chem. Soc. 1999, 121, 894 – 894;
´
[3] a) A. S. K. Hashmi, J. P. Weyrauch, M. Rudolph, E. Kurpejovic,
Angew. Chem. Int. Ed. 2004, 43, 6545 – 6547; Angew. Chem. 2004,
116, 6707 – 6709; b) A. S. K. Hashmi, M. Rudolph, J. P. Weyr-
auch, M. Wçlfle, W. Frey, J. W. Bats, Angew. Chem. Int. Ed. 2005,
44, 2798 – 2801; Angew. Chem. 2005, 117, 2858 – 2861; c) C.
Angew. Chem. Int. Ed. 2017, 56, 1 – 7
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

Angewandte
Communications
Chemie
c) N. M. Brunkan, M. R. Gagnꢀ, Organometallics 2002, 21,
4711 – 4717; d) J. J. Becker, P. S. White, M. R. Gagnꢀ, Organo-
metallics 2003, 22, 3245 – 3249.
Y. Takemoto, J. Org. Chem. 2007, 72, 4462 – 4468; d) T. Godet, C.
Vaxelaire, C. Michel, A. Milet, P. Belmont, Chem. Eur. J. 2007,
13, 5632 – 5641; e) S. Handa, L. M. Slaughter, Angew. Chem. Int.
Ed. 2012, 51, 2912 – 2915; Angew. Chem. 2012, 124, 2966 – 2969;
f) J.-R. Chen, X.-Q. Hu, W.-J. Xiao, Angew. Chem. Int. Ed. 2014,
53, 4038 – 4040; Angew. Chem. 2014, 126, 4118 – 4120; g) E.
Tomµs-Mendivil, J. Starck, J.-C. Ortuno, V. Michelet, Org. Lett.
2015, 17, 6126 – 6129.
[17] a) R. V. Parish, J. P. Wright, R. G. Pritchard, J. Organomet.
Chem. 2000, 596, 165 – 176; b) D. C. Behenna, B. M. Stoltz, J.
Am. Chem. Soc. 2004, 126, 15044 – 15045; c) M. Stol, D. J. M.
Snelders, J. J. M. de Pater, G. P. M. van Klink, H. Kooijman,
A. L. Spek, G. van Koten, Organometallics 2005, 24, 743 – 749;
d) K. Tani, D. C. Behenna, R. M. McFadden, B. M. Stoltz, Org.
Lett. 2007, 9, 2529 – 2531.
[19] W. Zi, F. D. Toste, J. Am. Chem. Soc. 2013, 135, 12600 – 12603.
[18] a) N. Asao, T. Nogami, K. Takahashi, Y. Yamamoto, J. Am.
Chem. Soc. 2002, 124, 764 – 765; b) X. Yao, C.-J. Li, Org. Lett.
2006, 8, 1953 – 1955; c) S. Obika, H. Kono, Y. Yasui, R. Yanada,
Manuscript received: December 17, 2016
Final Article published: && &&, &&&&
6
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 7
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
Ligand Effects
Gold(III) and C,O: Stable BINOL/gold-
(III) complexes adopting an unusual C,O-
chelation mode were synthesized by
a modular approach through combina-
tion of BINOLs and cyclometalated
gold(III) dichloride complexes. These
gold(III) complexes catalyzed acetaliza-
tion/cycloisomerization and carboalkoxy-
lation of ortho-alkynylbenzaldehydes with
trialkyl orthoformates.
J.-F. Cui, H.-M. Ko, K.-P. Shing, J.-R. Deng,
N. C.-H. Lai,
M.-K. Wong*
&&&& — &&&&
C,O-Chelated BINOL/Gold(III)
Complexes: Synthesis and Catalysis with
Tunable Product Profiles
Angew. Chem. Int. Ed. 2017, 56, 1 – 7
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
7
These are not the final page numbers!