Synthesis of Chiral Triarylmethanes Bearing All-Carbon Quaternary Stereocenters: Catalytic Asymmetric Oxidative Cross-Coupling of 2,2-Diarylacetonitriles and (Hetero)arenes

Article abstract of DOI:10.1002/anie.201912739

A direct and enantioselective oxidative cross-coupling of racemic 2,2-diarylacetonitriles with electron-rich (hetero)arenes has been described, which allows for efficient construction of triarylmethanes bearing all-carbon quaternary stereocenters with excellent chemo- and enantioselectivity. The reaction has an excellent functional group tolerance, and exhibits a broad scope with respect to both 2,2-diarylacetonitrile and (hetero)arene components. The rich chemistry of the cyano group allows for facile synthesis of other valuable chiral triarylmethanes bearing all-carbon quaternary centers that are otherwise difficult to access.

Full text of DOI:10.1002/anie.201912739

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International Edition: DOI: 10.1002/anie.201912739
German Edition: DOI: 10.1002/ange.201912739
Synthetic Methods
Synthesis of Chiral Triarylmethanes Bearing All-Carbon Quaternary
Stereocenters: Catalytic Asymmetric Oxidative Cross-Coupling of 2,2-
Diarylacetonitriles and (Hetero)arenes
Zehua Wang+, Yasheng Zhu+, Xiaoguang Pan, Gang Wang, and Lei Liu*
Abstract: A direct and enantioselective oxidative cross-cou-
pling of racemic 2,2-diarylacetonitriles with electron-rich
(hetero)arenes has been described, which allows for efficient
construction of triarylmethanes bearing all-carbon quaternary
stereocenters with excellent chemo- and enantioselectivity. The
reaction has an excellent functional group tolerance, and
exhibits a broad scope with respect to both 2,2-diarylacetoni-
trile and (hetero)arene components. The rich chemistry of the
cyano group allows for facile synthesis of other valuable chiral
triarylmethanes bearing all-carbon quaternary centers that are
otherwise difficult to access.
T
riarylmethanes are important structural motifs in medicinal
chemistry, materials science, and organic synthesis.[1] How-
ever, catalytic asymmetric synthesis of these molecules has
been a longstanding challenge owing to the lack of sufficient
steric difference between the aryl rings.[2] Since the pioneering
work by Yu and co-workers,[3] a couple of delicate strategies
for enantioselective preparation of triarylmethanes bearing
tertiary stereocenters have been disclosed.[4–6] However,
asymmetric construction of triarylmethanes containing all-
carbon quaternary stereocenters remains underexplored,
presumably because of the inherently unfavorable steric
hindrance.[7] In this context, Sun developed an elegant
enantioselective arylation of 1,1-diaryl tertiary alcohol or
1,1-diarylalkene moieties with heteroarenes, in which pre-
functionlization of the substrate is indispensable (Sche-
me 1A).[8]
Scheme 1. Overview of enantioselective construction of triaryl-substi-
tuted and cyano-substituted all-carbon quaternary centers.
À
C H components for quaternary all-carbon center formation
has remained understudied.[12–14] Herein, we report a direct
and asymmetric oxidative cross-coupling of racemic 2,2-
diarylacetonitriles with a range of electron-rich (hetero)ar-
enes for efficient construction of triaryl-cyano-substituted all-
carbon quaternary stereocenters (Scheme 1C). Further
manipulation of the nitrile moiety affords a platform to
access other valuable chiral triarylmethanes bearing all-
carbon quaternary centers that are otherwise difficult to
access.
Nitriles are common structural features spread across
bioactive natural products and synthetic pharmaceuticals. In
addition, nitrile moieties can also serve as valuable building
blocks because of their robust transformable properties.[9]
Existing studies on enantioselective construction of cyano-
substituted all-carbon quaternary stereocenters predomi-
nantly adopted a-nitrile carbanion chemistry involving the
cyano-bearing component as a nucleophile (Scheme 1B).[10,11]
In contrast, asymmetric oxidative coupling of two different
Asymmetric cross-coupling of the racemic 2,2-diarylace-
tonitrile 1a with the indole 2a was initially selected as a model
reaction for optimization (Table 1). Common oxidants for
À
benzylic C H bond cleavage, such as Ag2O, PhI(OAc)2, and
[*] Z. Wang,[+] G. Wang, Prof. Dr. L. Liu
School of Chemistry and Chemical Engineering
Shandong University, Jinan 250100 (P. R. China)
E-mail: leiliu@sdu.edu.cn
MnO2, proved to be futile (entry 1). When DDQ was used as
an oxidant, expected product 3a was isolated in 9% yield with
30% ee, though the majority of 1a was recovered (entry 2).
The low conversion might be ascribed to two factors: 1) DDQ
competitively reacts with 1a and 2a; 2) oxidation of 1a with
DDQ might be a reversible process. Next, a range of additives
were examined, and aluminum oxide (activated, basic) was
identified to be the best candidate, providing 3a in 77% yield
with 58% ee (entries 3–6). Chiral phosphoric acid catalysts
were extensively screened,[15] and the C2-symmetric imidodi-
Y. Zhu,[+] X. Pan, Prof. Dr. L. Liu
School of Pharmaceutical Sciences, Shandong University
Jinan 250012 (P. R. China)
[+] These authors contributed equally to this work.
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
https://doi.org/10.1002/anie.201912739.
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Table 1: Optimization of reaction conditions.[a]
Entry
Catalyst
Additive
Yield [%][b]
ee [%][c]
1[d]
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16[e]
17[f]
18[g]
C1
C1
C1
C1
C1
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C10
C10
C10
–
–
<5
9
n.d.
30
35
40
55
58
53
75
46
50
56
88
91
94
97
86
n.d.
53
K2CO3
3 ꢀ M.S.
20
51
71
77
79
81
61
66
63
80
82
86
88
79
<5
46
Al2O3, neutral
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
Al2O3, basic
[a] Reaction conditions: To 1a (0.1 mmol) in CH2Cl2 (3.0 mL) was
successively added DDQ (0.1 mmol), additive (40 mg), C (3 mol%), and
2a (0.12 mmol) at À788C for 12 h. [b] Yield of isolated product.
[c] Determined by chiral-phase HPLC analysis. [d] Ag2O, PhI(OAc)2, and
MnO2 as oxidant. [e] Dichloroethane as solvent at À408C. [f] Diethyl ether
as solvent. [g] Acetone as solvent. n.d.=not determined. M.S.=molecular Scheme 2. Scope with respect to 2,2-diarylacetonitriles.
sieves.
phosphoric acid C10 furnished highest level of enantiofacial
discrimination (entries 6–15).[15d] Optimization of the solvents
identified CH2Cl2 to be optimal (entries 16–18).
With the optimized reaction conditions in hand, the scope
of the enantioselective oxidative cross-coupling of racemic
2,2-diarylacetonitriles (1) with 2a was explored (Scheme 2).
In general, the diversely functionalized 2,2-diarylacetonitriles
1a–l and 1o–s, bearing a wide range of electronically varied
aryl groups with different substitution patterns, were compat-
ible with the reaction, providing the respective triarylme-
thanes 3a–3l and 3o–3s in 72–93% yields with up to 99%
ee.[16] Potential oxidation of ortho-positions of phenols to 1,2-
benzoquinones was not observed. Moreover, the polyarene
naphthalene substituted 1m and thiophene substituted 1n
proved to be suitable coupling partners.
The substituent effect of indoles was next evaluated
(Scheme 3). A broad range of indoles, bearing either electron-
donating or electron-withdrawing groups at different posi-
tions (C4, C5, C6, and C7) on the aryl rings, participated in the
Scheme 3. Scope with respect to the indole components. [a] C3
oxidative cross-coupling with 1a smoothly, affording the
(3 mol%) as catalyst.
2
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respective triarylmethanes 4a–i in 83–91% yields with 92–
98% ee. In addition, C2-substituted indoles were suitable
components, as demonstrated by the formation of the triaryl-
methane 4j in 80% yield with 94% ee.
Besides indole moieties, other (hetero)arenes were also
evaluated (Scheme 4). Electron-rich arenes such as the 1-
naphthol 5b and phenol 5c as well as 2-substituted pyrrole 5a
were identified to be competent coupling partners.[17,18] Aside
Scheme 4. Other (hetero)arene components. [a] C2 (3 mol%) used.
[b] C4 (3 mol%) used. [c] C5 (3 mol%) used.
from 2,2-diarylacetonitriles, the 2,2-diarylacetate 7 also
proved to be suitable electrophilic component, as demon-
strated by the formation of the triaryl-substituted acetate 8 in
53% yield with 85% ee (Scheme 5). While the reaction scope
was not exclusively explored, these results provide a proof-of-
concept for the modularity of the method for asymmetric
access to diversely functionalized triaryl-substituted all-
carbon quaternary stereocenters.
Scheme 6. Transformations of cross-coupling products.
ized chiral triarylmethanes bearing all-carbon quaternary
centers.
A series of control experiments were conducted to gain
further insights into the mechanism (Scheme 7). The racemic
2,2-diarylacetonitrile 1a was oxidized by DDQ, giving the d-
CN-d-phenyl-substituted p-quinone methide (QM) 13 in 90%
yield along with DDQH2 (2,3-dichloro-5,6-dicyanohydroqui-
none; Scheme 7a). Subjecting 13 to standard oxidative cross-
coupling conditions without DDQ provided 3a with compa-
rable ee value to that observed in the single-operation
process, thus indicating the intermediacy of p-QM 13
(Scheme 7b). The asymmetric oxidative coupling was then
performed stepwise to understand the reaction details (Sche-
me 7c). Once the oxidation of 1a by DDQ was complete, as
monitored by TLC analysis, C10 and 2a were added to the
reaction mixture. Surprisingly, 3a was only isolated in 6%
yield, and 1a was recovered in 86% yield, indicating the
reversibility of the oxidation process. No reaction was
observed for 13 and DDQH2 (Scheme 7d). No reaction was
observed for the methyl-protected substrate 14, implying the
importance of the hydroxy moiety in p-QM intermediate
generation (Scheme 7e). Based on the above results, a plau-
sible mechanism is suggested (Scheme 7 f). 1a is oxidized by
DDQ in a reversible process, furnishing intermediate 17,
which might be stable in reaction system. Al2O3 might
promote irreversible collapse of 17, affording DDQH2 along
with p-QM 13 for subsequent enantioselective 1,6-conjugate
addition, though the origin of this curious but useful effect has
not been clear.[19] Asymmetric 1,6-conjugate addition was not
influenced by stoichiometric DDQH2 (Scheme 7g). The N-
methyl-protected indole 18 was found to be a less competent
coupling partner than 2a, thus suggesting the importance of
Scheme 5. Oxidative cross-coupling with 2,2-diarylacetate.
The synthetic applications of the method were next
illustrated (Scheme 6). The removable/convertible feature
of the phenolic hydroxy group was verified. The hydroxy
moiety was removed through triflation followed by Pd-
catalyzed hydrogenation, as demonstrated by the conversion
of 3c into 9 in 90% yield (Scheme 6a). In addition, the
hydroxy group in 3a can also undergo triflation followed by
Pd-catalyzed cross-coupling reaction, furnishing the biaryl 10
in high efficiency (Scheme 6b). The nitrile group can be
converted into an array of valuable functionality. For
example, nitriles can be reduced by DIBAL-H to aldehydes,
as demonstrated by the transformation of 3a into 11 in good
yield and with complete retention of stereochemistry (Sche-
me 6c). Alternatively, hydrolysis of the nitrile proceeded
smoothly using tert-amyl alcohol under basic conditions,
yielding the corresponding amide 12 in 92% ee (Scheme 6d).
Notably, no obvious enantiopurity erosion has been observed
in these transformations, thus demonstrating the reliability of
the method in practical preparation of diversely functional-
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(Scheme 7i). The proposed pseudo-intra-
molecular mode is in agreement with the
observed excellent remote stereocontrol.
In summary, a direct and enantioselec-
tive oxidative cross-coupling of racemic 2,2-
diarylacetonitriles with (hetero)arenes has
been described, allowing efficient construc-
tion of triarylmethanes bearing all-carbon
quaternary stereocenters with excellent
chemo- and enantioselectivities. The
single-operation reaction has an excellent
functional-group tolerance and exhibits
a broad scope with respect to both 2,2-
diarylacetonitrile and (hetero)arene compo-
nents. The rich chemistry of the cyano group
allows facile synthesis of other valuable
chiral triarylmethanes bearing all-carbon
quaternary centers that are otherwise diffi-
cult to access.
Acknowledgements
We gratefully acknowledge the National
Science Foundation of China (21722204,
21971148, and 21432003).
Conflict of interest
The authors declare no conflict of interest.
Keywords: asymmetric catalysis · nitrile ·
À
oxidative C H functionalization ·
quaternary stereocenter · triarylmethane
[1] a) D. F. Duxbury, Chem. Rev. 1993, 93, 381;
b) M. S. Shchepinov, V. A. Korshunb, Chem.
Soc. Rev. 2003, 32, 170; c) V. Nair, S. Thomas,
S. C. Mathew, K. G. Abhilash, Tetrahedron
2006, 62, 6731; d) M. Shiri, M. A. Zolfigol,
H. G. Kruger, Z. Tanbakouchian, Chem. Rev.
2010, 110, 2250; e) S. Mondal, G. Panda, RSC
Adv. 2014, 4, 28317.
[2] a) J. A. Ellman, T. D. Owens, T. P. Tang, Acc.
Chem. Res. 2002, 35, 984; b) F. Schmidt, R. T.
Stemmler, J. Rudolph, C. Bolm, Chem. Soc.
Rev. 2006, 35, 454; c) M. Nambo, C. M.
Crudden, ACS Catal. 2015, 5, 4734.
[3] B.-F. Shi, N. Maugel, Y.-H. Zhang, J.-Q. Yu,
Angew. Chem. Int. Ed. 2008, 47, 4882;
Angew. Chem. 2008, 120, 4960.
Scheme 7. Mechanistic studies.
[4] Stereospecific arylation of enantiomerically enriched diary-
lmethyl esters or borons, see: a) B. L. H. Taylor, M. R. Harris,
E. R. Jarvo, Angew. Chem. Int. Ed. 2012, 51, 7790; Angew. Chem.
2012, 124, 7910; b) M. R. Harris, L. E. Hanna, M. A. Greene,
C. E. Moore, E. R. Jarvo, J. Am. Chem. Soc. 2013, 135, 3303;
c) Q. Zhou, H. D. Srinivas, S. Dasgupta, M. P. Watson, J. Am.
Chem. Soc. 2013, 135, 3307; d) S. C. Matthew, B. W. Glasspoole,
the N-H moiety, presumably as a hydrogen-bond donor
(Scheme 7h). Based on the above analysis, a plausible tight
transition state is proposed, in which chiral phosphoric acid
acts as a bifunctional role for activation of both coupling
partners and remote stereocontrol by hydrogen bonding
4
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These are not the final page numbers!

Angewandte
Communications
Chemie
P. Eisenberger, C. M. Crudden, J. Am. Chem. Soc. 2014, 136,
5828; e) Y. Lou, P. Cao, T. Jia, Y. Zhang, M. Wang, J. Liao,
Angew. Chem. Int. Ed. 2015, 54, 12134; Angew. Chem. 2015, 127,
12302.
[12] Selected reviews on asymmetric oxidative coupling of two
À
different C H bonds, see: a) C.-J. Li, Acc. Chem. Res. 2009, 42,
335; b) C. Liu, H. Zhang, W. Shi, A. Lei, Chem. Rev. 2011, 111,
1780; c) C. Zheng, S.-L. You, RSC Adv. 2014, 4, 6173; d) Y. Qin,
J. Lv, S. Luo, Tetrahedron Lett. 2014, 55, 551; e) L. Yang, H.
Huang, Catal. Sci. Technol. 2012, 2, 1099.
[5] Asymmetric Friedel–Crafts reactions, see: a) F.-L. Sun, M. Zeng,
Q. Gu, S.-L. You, Chem. Eur. J. 2009, 15, 8709; b) F.-L. Sun, X.-J.
Zheng, Q. Gu, Q.-L. He, S.-L. You, Eur. J. Org. Chem. 2010, 47;
c) S. Saha, S. K. Alamsetti, C. Schneider, Chem. Commun. 2015,
51, 1461; d) H.-H. Liao, A. Chatupheeraphat, C.-C. Hsiao, I.
Atodiresei, M. Rueping, Angew. Chem. Int. Ed. 2015, 54, 15540;
Angew. Chem. 2015, 127, 15760; e) C. Yue, F. Na, X. Fang, Y.
Cao, J. C. Antilla, Angew. Chem. Int. Ed. 2018, 57, 11004; Angew.
Chem. 2018, 130, 11170.
À
[13] Existing asymmetric oxidative coupling of two C H bonds
À
predominantly focused on C H bonds adjacent to a heteroatom.
For nitrogen, see: a) Z. Li, C.-J. Li, Org. Lett. 2004, 6, 4997; b) J.
Zhang, B. Tiwari, C. Xing, X. Chen, Y. R. Chi, Angew. Chem. Int.
Ed. 2012, 51, 3649; Angew. Chem. 2012, 124, 3709; c) D. A.
DiRocco, T. Rovis, J. Am. Chem. Soc. 2012, 134, 8094; d) G.
Zhang, Y. Ma, S. Wang, Y. Zhang, R. Wang, J. Am. Chem. Soc.
2012, 134, 12334; e) Y. Tan, W. Yuan, L. Gong, E. Meggers,
Angew. Chem. Int. Ed. 2015, 54, 13045; Angew. Chem. 2015, 127,
[6] Asymmetric arylation of quinone methides, see: a) Y. Huang, T.
Hayashi, J. Am. Chem. Soc. 2015, 137, 7556; b) V. Reddy, R. V.
Anand, Org. Lett. 2015, 17, 3390.
ˇ
13237; f) G. Wei, C. Zhang, F. Bures, X. Ye, C.-H. Tan, Z. Jiang,
[7] a) K. Fuji, Chem. Rev. 1993, 93, 2037; b) I. Denissova, L.
Barriault, Tetrahedron 2003, 59, 10105; c) M. Shimizu, Angew.
Chem. Int. Ed. 2011, 50, 5998; Angew. Chem. 2011, 123, 6122;
d) J. Christoffers, A. Mann, Angew. Chem. Int. Ed. 2001, 40,
4591; Angew. Chem. 2001, 113, 4725; e) Y. Liu, S.-J. Han, W.-B.
Liu, B. M. Stoltz, Acc. Chem. Res. 2015, 48, 740; f) X.-P. Zeng,
Z.-Y. Cao, Y.-H. Wang, F. Zhou, J. Zhou, Chem. Rev. 2016, 116,
7330.
[8] a) W. Zhao, Z. Wang, B. Chu, J. Sun, Angew. Chem. Int. Ed. 2015,
54, 1910; Angew. Chem. 2015, 127, 1930; b) Z. Wang, F. Ai, Z.
Wang, W. Zhao, G. Zhu, Z. Lin, J. Sun, J. Am. Chem. Soc. 2015,
137, 383; c) Z. Wang, Y. F. Wong, J. Sun, Angew. Chem. Int. Ed.
2015, 54, 13711; Angew. Chem. 2015, 127, 13915; d) J.-S. Lin, T.-
T. Li, J.-R. Liu, G.-Y. Jiao, Q.-S. Gu, J.-T. Cheng, Y.-L. Guo, X.
Hong, X.-Y. Liu, J. Am. Chem. Soc. 2019, 141, 1074; also see
a two-step synthetic protocol: e) K. Tsuchida, Y. Senda, K.
Nakajima, Y. Nishibayashi, Angew. Chem. Int. Ed. 2016, 55,
9728; Angew. Chem. 2016, 128, 9880.
ACS Catal. 2016, 6, 3708; g) Q. Yang, L. Zhang, C. Ye, S. Luo, L.-
Z. Wu, C.-H. Tung, Angew. Chem. Int. Ed. 2017, 56, 3694;
Angew. Chem. 2017, 129, 3748; for oxygen, see: h) Z. Meng, S.
Sun, H. Yuan, H. Lou, L. Liu, Angew. Chem. Int. Ed. 2014, 53,
543; Angew. Chem. 2014, 126, 553; i) A. Lee, R. C. Betori, E. A.
Crane, K. A. Scheidt, J. Am. Chem. Soc. 2018, 140, 6212; for
À
benzylic C H bond, see: j) F. Benfatti, M. Guiteras Capdevila,
L. Zoli, E. Benedetto, P. G. Cozzi, Chem. Commun. 2009, 5919;
k) C. Guo, J. Song, S. W. Luo, L. Z. Gong, Angew. Chem. Int. Ed.
2010, 49, 5558; Angew. Chem. 2010, 122, 5690; l) B. Zhang, S.-K.
Xiang, L.-H. Zhang, Y. Cui, N. Jiao, Org. Lett. 2011, 13, 5212;
m) E. Larionov, M. M. Mastandrea, M. A. Pericꢀs, ACS Catal.
2017, 7, 7008; n) S. Narute, D. Pappo, Org. Lett. 2017, 19, 2917.
[14] Selected examples of enantioselective oxidative coupling of two
À
C H components for formation of quaternary all-carbon
centers: a) H. Wu, Y.-P. He, L. Xu, D.-Y. Zhang, L.-Z. Gong,
Angew. Chem. Int. Ed. 2014, 53, 3466; Angew. Chem. 2014, 126,
3534; b) W. Cao, X. Liu, R. Peng, P. He, L. Lin, X. Feng, Chem.
Commun. 2013, 49, 3470.
[9] a) R. C. Larock, Comprehensive Organic Transformations: A
Guide to Functional Group Preparation, VCH, New York, 1989;
b) V. Y. Kukushkin, A. J. L. Pombeiro, Chem. Rev. 2002, 102,
1771; c) P. Pollak, G. Romeder, F. Hagedorn, H.-P. Gelbke,
Nitriles in Ullmanꢀs Encycloped-Ia of Industrial Chemistry,
Wiley-VCH, Weinheim, 2012.
[15] a) T. Akiyama, Chem. Rev. 2007, 107, 5744; b) M. Terada,
ˇ
´
Synthesis 2010, 1929; c) I. Coric, B. List, Nature 2012, 483, 315;
d) D. Parmar, E. Sugiono, S. Raja, M. Rueping, Chem. Rev. 2014,
114, 9047.
[16] The absolute configuration was assigned by X-ray diffraction
analysis.
[17] The absolute configuration was assigned by employing CD
spectroscopy measurements and theoretical calculations. See the
Supporting Information for details.
[18] No reaction was observed for simple phenol as the coupling
partner.
[19] Asymmetric manipulation of p-QMs bearing an electron-with-
drawing group at d-position has never been explored to date. For
[10] a) M. Sawamura, M. Sudoh, Y. Ito, J. Am. Chem. Soc. 1996, 118,
3309; b) A. H. Mermerian, G. C. Fu, Angew. Chem. Int. Ed.
2005, 44, 949; Angew. Chem. 2005, 117, 971; c) S. E. Denmark,
T. W. Wilson, M. T. Burk, J. R. Heemstra, Jr., J. Am. Chem. Soc.
2007, 129, 14864; d) S. Jautze, R. Peters, Angew. Chem. Int. Ed.
2008, 47, 9284; Angew. Chem. 2008, 120, 9424; e) L. Yin, M.
Kanai, M. Shibasaki, J. Am. Chem. Soc. 2009, 131, 9610; f) B. M.
Trost, J. R. Miller, C. M. Hoffman, Jr., J. Am. Chem. Soc. 2011,
133, 8165; g) H. Kawai, S. Okusu, E. Tokunaga, H. Sato, M.
Shiro, N. Shibata, Angew. Chem. Int. Ed. 2012, 51, 4959; Angew.
Chem. 2012, 124, 5043; h) J. Zhao, X. Liu, W. Luo, M. Xie, L. Lin,
X. Feng, Angew. Chem. Int. Ed. 2013, 52, 3473; Angew. Chem.
2013, 125, 3557; i) B. W. H. Turnbull, P. A. Evans, J. Am. Chem.
Soc. 2015, 137, 6156; j) L. Dai, L. Lin, J. Zheng, D. Zhang, X. Liu,
X. Feng, Org. Lett. 2018, 20, 5314; k) J. Zheng, L. Lin, L. Dai, Q.
Tang, X. Liu, X. Feng, Angew. Chem. Int. Ed. 2017, 56, 13107;
Angew. Chem. 2017, 129, 13287.
À
selected examples of asymmetric C C bond formation involving
p-QM substrates with an aryl group at d-position, see: a) W.-D.
Chu, L.-F. Zhang, X. Bao, X.-H. Zhao, C. Zeng, J.-Y. Du, G.-B.
Zhang, F.-X. Wang, X.-Y. Ma, C.-A. Fan, Angew. Chem. Int. Ed.
2013, 52, 9229; Angew. Chem. 2013, 125, 9399; b) L. Caruana, F.
Kniep, T. K. Johansen, P. H. Poulsen, K. A. Jørgensen, J. Am.
Chem. Soc. 2014, 136, 15929; c) S. Li, Y. Liu, B. Huang, T. Zhou,
H. Tao, Y. Xiao, L. Liu, J. Zhang, ACS Catal. 2017, 7, 2805.
[11] a) Y. Zhang, L. Lin, Y. Chen, X. Liu, X. Feng, Adv. Synth. Catal.
2017, 359, 1831; b) S. Jayakumar, K. Louven, C. Strohmann, K.
Kumar, Angew. Chem. Int. Ed. 2017, 56, 15945; Angew. Chem.
2017, 129, 16161.
Manuscript received: October 5, 2019
Revised manuscript received: October 31, 2019
Version of record online: && &&, &&&&
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Chemie
Communications
Synthetic Methods
Z. Wang, Y. Zhu, X. Pan, G. Wang,
L. Liu*
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Synthesis of Chiral Triarylmethanes
Bearing All-Carbon Quaternary
Stereocenters: Catalytic Asymmetric
Oxidative Cross-Coupling of 2,2-
Diarylacetonitriles and (Hetero)arenes
A direct and enantioselective oxidative
cross-coupling of racemic 2,2-diarylace-
tonitriles with electron-rich (hetero)ar-
enes allows for efficient construction of
triarylmethanes bearing all-carbon qua-
ternary stereocenters with excellent
chemo- and enantioselectivity. The rich
chemistry of the cyano group leads to
facile syntheses of other valuable chiral
triarylmethanes bearing all-carbon qua-
ternary centers that are otherwise difficult
to access.
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Angew. Chem. Int. Ed. 2020, 59, 1 – 6
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