Copper-catalyzed asymmetric silyl addition to alkenyl-substituted N -heteroarenes

Article abstract of DOI:10.1039/c9cc08910a

Asymmetric conjugate addition of PhMe₂SiBPin to a wide range of N-heteroaryl alkenes proceeded in the presence of a copper catalyst coordinated with an easily accessible chiral phosphoramidite ligand to afford useful β-silyl N-heteroarenes in high yields (up to 96%) and excellent enantioselectivities (up to 97% ee).

Full text of DOI:10.1039/c9cc08910a

View Article Online
View Journal
ChemComm
Chemical Communications
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: Y. Zeng, B. Chen,
Y. Wang, C. He, Z. Mu, J. Du, L. HE, W. Chu and Q. Liu, Chem. Commun., 2020, DOI:
10.1039/C9CC08910A.
Volume 54
This is an Accepted Manuscript, which has been through the
Number
January 2018
Pages 1-112
1
4
Royal Society of Chemistry peer review process and has been
accepted for publication.
ChemComm
Chemical Communications
rsc.li/chemcomm
Accepted Manuscripts are published online shortly after acceptance,
before technical editing, formatting and proof reading. Using this free
service, authors can make their results available to the community, in
citable form, before we publish the edited article. We will replace this
Accepted Manuscript with the edited and formatted Advance Article as
soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes to the
text and/or graphics, which may alter content. The journal’s standard
Terms & Conditions and the Ethical guidelines still apply. In no event
shall the Royal Society of Chemistry be held responsible for any errors
or omissions in this Accepted Manuscript or any consequences arising
from the use of any information it contains.
ISSN 1359-7345
COMMUNICATION
S. J. Connon, M. O. Senge et al.
Conformational control of nonplanar free base porphyrins:
towards bifunctional catalysts of tunable basicity
rsc.li/chemcomm

Please do not adjust margins
Page 1 of 5
ChemComm
View Article Online
DOI: 10.1039/C9CC08910A
COMMUNICATION
Copper-Catalyzed Asymmetric Silyl Addition to Alkenyl-
Substituted N-Heteroarenes
Ya-Li Zeng,a Bo Chen,a Ya-Ting Wang,a Cheng-Yu He,a Zi-Yuan Mu,a Ji-Yuan Du,b Long He,c Wen-Dao
Received 00th January 20xx,
Accepted 00th January 20xx
Chu,*,a and Quan-Zhong Liu*,a
DOI: 10.1039/x0xx00000x
Asymmetric conjugate addition of PhMe2SiBPin to a wide range of group,6 and the C-Si bond can also be readily transformed into
N-heteroaryl alkenes proceeded in the presence of a copper C−C bond.7 Accordingly, the vital objective in this area of
catalyst coordinated with an easily accessible chiral research is to develop efficient and practical ways to chiral
phosphoramidite ligand to afford useful β-silyl N-heteroarenes in silanes. Among the available approaches to provide chiral
high yields (up to 96%) and excellent enantioselectivities (up to 97% organosilicon compounds, asymmetric silyl conjugate addition
ee).
to electron-deficient alkenes is one of the most reliable ways.8-
13 In 1988, Hayashi and Ito’s group pioneered the development
of enantioselective disilylation of enones using palladium
N-Containing heteroarenes are very important structural units,
which are commonly found in a wide variety of natural products
and pharmaceutically active compounds. Although elaboration
of the N-containing heteroarenes continues to be the main
approach to access functionalized heterocyclic aromatic
compounds, exploration of asymmetric conjugate addition of
nucleophiles to alkenes activated by adjacent N-containing
heteroarenes has gained prominence in the last decade
(Scheme 1a).1 Key contributions in the area include transition
metal-catalyzed asymmetric arylation and hydrogenation of
alkenyl azaarenes, reported by Lam and co-workers.2
Additionally, other groups presented elegant, highly
enantioselective conjugate additions to N-heteroaryl alkenes
using pyrazoles,3c Grignard reagents,3d-e B2(pin)23f and thiols3h as
nucleophiles respectively. However, contrary to common
Michael acceptors, such as α,β-unsaturated carbonyl, nitro,
nitrile and sulfonyl compounds, which have been widely studied
in asymmetric conjugate addition,4 alkenyl azaarenes have
received little attention.3 The scarcity of available asymmetric
approaches is attributed to the low activation from the N-
heteroaryl group and the generation of unfavorable
intermediates through a transient dearomatization step.
catalysis.8
Subsequently,
the
reaction scope and
catalytic systems were expanded by Oestreich,9 Hoveyda,10
Córdova,11 Procter12 and Kobayashi.13 Although significant
progress has been achieved with regard to asymmetric silylation
a) Previous work (ref. 3)

N
R
N
R

Chiral catalyst
X
X
Nu
Nu
X = C, N, O, S
Nu = H, C, N, S, B
b) Oestreich's work (ref. 14)
PPh2
Me
L*
CuCl/
BF3 OEt2, Me2PhSiMgBr
toluene/Et2O, 78 o
Cy2P
Fe
N
SiMe2Ph
Ar
N
R1
R1
C
O
O
Ar
L*
61-93% ee
c) This work
L*
Cu(MeCN)4PF6/
O
O
N
Ar
N
Ar
PhMe2SiBPin, NaOtBu
P
N
O
MeOH, THF, rt
X
X
SiMe2Ph
L*
Quinoline
good yields and scalable
excellent stereoselectivities
operationally simple, at room temperature
easily accessible chiral phosphoramidite ligands and silylating agents
Isoquinoline
Benzoxazole
Benzothiazole
Scheme 1 Catalytic asymmetric nucleophilic addition to alkenyl
Chiral silanes are versatile intermediates in organic
synthesis.5 The silicon motif is widely used as a masked hydroxyl
azaarenes.
of a wide range of cyclic and acyclic α, β-unsaturated carbonyl
systems, a few studies on silyl transfer to alkenes conjugated to
weaker electron-withdrawing groups, and in particular alkenyl-
substituted N-heterocycles, have been described. The topic still
represents a challenge. Very recently, Oestreich reported the
first Cu(I)-catalyzed asymmetric conjugate addition of silicon
Grignard reagents to poorly reactive alkenyl heteroarenes with
Lewis acid activation (Scheme 1b).14 Because of high activity of
the silicon Grignard reagents, the reactions must be carried out
at very low temperature.14-15 Although this work marks a
a. Chemical Synthesis and Pollution Control, Key Laboratory of Sichuan Province,
College of Chemistry and Chemical Engineering, China West Normal University,
No. 1, Shida Road, Nanchong 637002, China
Email:chuwendaonpo@126.com, quanzhongliu@cwnu.edu.cn
b. College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng,
Shandong 252059, China
c. College of Chemistry and Materials Engineering, Guiyang University,
Guiyang 550005, China
† Electronic supplementary information (ESI) available: Experimental procedures,
analytical data, and copies of NMR and HPLC spectra, including X-ray crystal
structures of 2b. CCDC 1955733. For ESI and crystallographic data in CIF or other
electronic format See DOI: 10.1039/x0xx00000x
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 2 of 5
COMMUNICATION
Journal Name
significant breakthrough, the enantioselective reaction is effective in asymmetric induction, presenting 57%
View Article Online
DOI: 10.1039/C9CC08910A
limited to benzoxazole-derived substrates and the ee values are enantioselectivity and 19% yield (entry 3). Encouraged by this
moderate in most cases. Thus, further development of catalytic result, the substituents on the nitrogen atom were examined.
highly enantioselective silyl addition to alkenes activated by The morpholine moiety (L9) was superior to others, such as
other azaaryl groups with an easily obtained catalyst is urgently other acyclic amines (L4-L6), pyrrolidine (L7) and indoline (L8),
demanded. Herein, we describe an operationally simple, highly affording 2a in 86% yield with 93% ee (entries 4-9). Additionally,
chemo- and enantioselective silylation protocol of a wide range we evaluated the effects of solvent on the reaction. It was found
of N‑heteroaryl-substituted alkenes using PhMe2SiBpin16-17 as that the reaction in Et2O, hexane, toluene and DMF all provided
the nucleophile and chiral phosphoramidite/Cu(I) as the the product 2a with similarly high ee, but the yields varied
catalyst (Scheme 1c). PhMe2SiBpin is readily available, bench- greatly and the reaction in THF gave the highest yield (entries 9-
stable, and easy-to-handle. Since Suginome and Ito first 13).
introduced it in Pd-catalyzed silaboration of alkynes,16 the
development of PhMe2SiBpin chemistry has been the subject of
intense research in recent years.17
Table 2 Substrate scopea.
Cu(MeCN)4PF6 (10 mol %)
N
Ar
N
Ar
L9
(22 mol %), PhMe2SiBPin (2.0 equiv)
NaOtBu (0.2 equiv), MeOH (4.0 equiv)
X
X
SiMe2Ph
Table 1 Optimization of the reaction conditionsa.
THF, rt, 12 h
1
2
Cu(MeCN)4PF6 (10 mol %)
SiMe2Ph


L
(22 mol %), PhMe2SiBPin (2.0 equiv)
SiMe2Ph
SiMe2Ph
N
N
NaOtBu (0.2 equiv), MeOH (4.0 equiv)
N
N
solvent, rt, 24 h
1a
2a
Cl
2a
(86% yield, 93% ee)
2b
(90% yield, 90% ee)
2b
x-ray of
entry
1d
2d
3
4
5
6
7
8
9
ligand
L1
L2
L3
L4
L5
L6
L7
L8
L9
L9
L9
L9
solvent
THF
THF
THF
THF
THF
THF
THF
THF
yield (%)b
44
39
19
48
32
22
64
49
86
69
66
58
ee (%)c
0
5
SiMe2Ph
SiMe2Ph
SiMe2Ph
F
Cl
N
N
N
Br
2c
2f
(82% yield, 90% ee)
2d
2g
2e
2h
(95% yield, 91% ee)
(94% yield, 90% ee)
57
83
85
85
89
91
93
93
90
93
89
SiMe2Ph
SiMe2Ph
SiMe2Ph
CF3
N
N
N
F
Cl
(92% yield, 90% ee)
(82% yield, 94% ee)
(94% yield, 97% ee)
SiMe2Ph
SiMe2Ph
SiMe2Ph
Me
N
N
N
THF
CF3
Br
2i
2l
2j
2k
2n
(95% yield, 94% ee)
(89% yield, 90% ee)
(87% yield, 91% ee)
10
11
12
13
Et2O
hexane
toluene
DMF
SiMe2Ph
SiMe2Ph
SiMe2Ph
OMe
N
N
N
OMe
tBu
L9
48
(89% yield, 88% ee)
2m
(90% yield, 94% ee)
(81% yield, 93% ee)
aReaction conditions: 1a (0.1 mmol), PhMe2SiBpin (0.2 mmol),
NaOtBu (0.2 equiv), Cu(MeCN)4PF6 (10 mol %), ligand (22 mol
%), MeOH (4.0 equiv), solvent (0.05 M). bIsolated yield.
cDetermined by chiral HPLC. d0.11 equiv of ligand was
employed.
SiMe2Ph
SiMe2Ph
SiMe2Ph
N
N
N
O
Ph
O
2o
2p
2s
2q
(86% yield, 90% ee)
SiMe2Ph
(81% yield, 89% ee)
(80% yield, 88% ee)
SiMe2Ph
SiMe2Ph
N
O
N
N
Ph
S
S
O
O
Ph
Ph
O
O
2r
2t
(76% yield, 85% ee)
(80% yield, 85% ee)
(96% yield, 91% ee)
Ph2
Ph2
Ph2
Ph2
P
N
MeO
Br
Me
SiMe2Ph
SiMe2Ph
SiMe2Ph
O
N
N
N
L1
L2
L3
F
F
F
2u
2v
2w
(78% yield, 86% ee)
(69% yield, 87% ee)
(90% yield, 91% ee)
O
O
O
O
R
R
N
SiMe2Ph
O
SiMe2Ph
SiMe2Ph
P
N
P
N
P
N
X
N
Cl
N
O
O
F
2x
2y
2z
(81% yield, 85% ee)
(88% yield, 93% ee)
(88% yield, 95% ee)
L4
L5
L6
, R = Me
, R = Cyclohexyl
, R = Bn
L8
L9
, X = CH2
, X = O
L7
S
SiMe2Ph
SiMe2Ph
SiMe2Ph
SiMe2Ph
n-Bu
N
N
N
N
F
Initially, we selected 2-alkenylquinoline 1a and PhMe2SiBpin
as model substrates to study the silylation reaction (Table 1).18
Racemic product 2a was produced in low yield in the presence
of Cu(MeCN)4PF6, bidentate chiral phosphine ligand (L1 or L2)
and NaOtBu in THF at room temperature (entries 1-2). To our
delight, chiral phosphoramidite ligand L3 was found to be
2zc
2zd
N.D.
2zb N.D.
N.D.
2za
(89% yield, 90% ee)
aReaction conditions: 1 (0.1 mmol), PhMe2SiBpin (0.2 mmol),
NaOtBu (0.2 equiv), Cu(MeCN)4PF6 (10 mol %), L9 (22 mol %),
MeOH (4.0 equiv), THF (0.05 M). Yield of isolated product 2. Ee
determined by HPLC analysis. N.D. = not detected.
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 5
ChemComm
Please do not adjust margins
Journal Name
COMMUNICATION
With the optimal conditions in hand, the substrate scope was
then examined (Table 2). A wide range of alkenyl quinolines
bearing electron-neutral, -deficient or -rich β-aromatic
substituents reacted efficiently with PhMe2SiBpin to afford the
corresponding products 2a-q in 80-95% yields and 88-97% ee.
The absolute configuration of 2b was unambiguously
established by X-ray crystallographic analysis.19 Substrates with
2- and 3-thienyl groups were also amenable to this protocol to
produce the corresponding products 2r-s with high yields and
enantioselectivities. Interestingly, when the silylation of
conjugate divinyl quinoline 1t was investigated, there was only
1,4-addition and the corresponding adduct 2t was isolated in
76% yield with 85% ee. The substituents (such as Br, Me, OMe
or Cl) on the quinoline ring of 1 did not compromise the
View Article Online
DOI: 10.1039/C9CC08910A
LnCu OtBu
or
SiMe2Ph
Ph
PhMe2SiBPin
LnCu OMe
N
2a
MeOH
ButO Bpin
SiMe2Ph
Ph
LnCu SiMe2Ph
N
I
CuLn
III
N
Ph
1a
H
Ph
N
H
LnCu SiMe2Ph
II
enantioselectivities of 2u-x. Other heteroaromatic substrates, Scheme 3 Proposed catalytic cycle.
such as isoquinoline (1y), benzoxazole (1z) and benzothiazole
In conclusion, we have developed an operationally simple
and highly enantioselective Cu(I)-catalyzed conjugate addition
of PhMe2SiBPin to a wide range of alkenyl N-heteroarenes with
easily accessible chiral phosphoramidite as the ligand. A series
of useful β-silyl N-heteroarenes were achieved in high yields
and ees. Moreover, the reaction can be effectively performed
at room temperature on gram scale.
(1za), were also suitable for the reaction and the corresponding
silylated products 2y-2za were obtained with excellent results
(81-89% yield, 85-95% ee). Finally, the reactions between
PhMe2SiBpin and alkyl-substituted 1zb, α,β-disubstituted 1zc or
β,β-disubstituted 1zd were also attempted, but they were
unsuccessful.
We thank Department of Science and Technology of Sichuan
Province (2019YJ0339) and NSFC (21572183, 21772158,
21801208) for financial support.
Cu(MeCN)4PF6 (10 mol %)
SiMe2Ph
L9
(22 mol %), PhMe2SiBPin (2.0 equiv)
(a)
(b)
(c)
N
N
NaOtBu (0.2 equiv), MeOH (4.0 equiv)
THF, rt, 12 h
Br
2i
Br
Br
Br
1i
(2.5 mmol)
(94% yield, 94% ee)
OH
1) HBF4, DCM, 0 o
C
Conflicts of interest
There are no conflicts to declare.
N
2) KF, KHCO3,THF/MeOH, 0 o
then aq. H2O2 (30%), rt
C
SiMe2Ph
3
N
(60% yield, 94% ee)
Br
2i
(94% ee)
COOMe
N
1) TBAT, CO2 balloon, DMSO
2) CH3I, 30 o
C
Notes and references
4
(50% yield)
1
Reviews: (a) D. Best and H. W. Lam, J. Org. Chem. 2014, 79,
831; (b) D. A. Klumpp, Synlett, 2012, 23, 1590.
Scheme 2 Scale-up experiment and synthetic applications of
compound 2i.
2
(a) L. Rupnicki, A. Saxena and H. W. Lam, J. Am. Chem. Soc.,
2009, 131, 10386; (b) G. Pattison, G. Piraux and H. W. Lam, J.
Am. Chem. Soc., 2010, 132, 14373; (c) A. Saxena and H. W.
Lam, Chem. Sci., 2011, 2, 2326; (d) A. Saxena, B. Choi and H.
W. Lam, J. Am. Chem. Soc., 2012, 134, 8428; (e) I. D. Roy, A. R.
Burns, G. Pattison, B. Michel, A. J. Parker and H. W. Lam,
Chem. Commun., 2014, 50, 2865; (f) B. Choi, A. Saxena, J. J.
Smith, G. H. Churchill and H. W. Lam, Synlett, 2015, 26, 350;
(g) J. J. Smith, D. Best and H. W. Lam, Chem. Commun., 2016,
52, 3770.
(a) A. A. Friedman, J. Panteleev, J. Tsoung, V. Huynh and M.
Lautens, Angew. Chem. Int. Ed., 2013, 52, 9755; (b) S. Wang,
X. Li, H. Liu, L. Xu, J. Zhuang, J. Li, H. Li and W. Wang, J. Am.
Chem. Soc., 2015, 137, 2303; (c) Y.-Y. Wang, K. Kanomata, T.
Korenaga and M. Terada, Angew. Chem. Int. Ed., 2016, 55,
927; (d) R. P. Jumde, F. Lanza, M. J. Veenstra and S. R.
Harutyunyan, Science, 2016, 352, 433; (e) R. P. Jumde, F.
Lanza, T. Pellegrini and S. R. Harutyunyan, Nat. Commun.,
2017, 8, 2058; (f) L. Wen, Z. Yue, H. Zhang, Q. Chong and F.
Meng, Org. Lett., 2017, 19, 6610; (g) Y. Yin, Y. Dai, H. Jia, J. Li,
L. Bu, B. Qiao, X. Zhao and Z. Jiang, J. Am. Chem. Soc., 2018,
140, 6083; (h) M. Formica, G. Sorin, A. J. M. Farley, J. Díaz, R.
S. Paton and D. J. Dixon, Chem. Sci., 2018, 9, 6969.
The reaction on a gram scale (2.5 mmol of 1i) was also
performed to obtain the 1,4-adduct 2i with 94% ee and 94%
yield (Scheme 2a). A key synthetic transformation of the silicon
motif is that it can be used as a masked hydroxyl group.6 The
compound 2i could be transformed into alcohol 3 through
Tamao-Fleming oxidation20 without erosion of stereoselectivity
(Scheme 2b). Furthermore, the treatment of 2i in the presence
of TBAT and CO2 could provide the desired ester 4 in 50%
yield.17k Unfortunately, no chirality transformation was
observed in this reaction (Scheme 2c).
A possible mechanism for the reactions was illustrated in
Scheme 3. LnCu-alkoxides react with PhMe2SiBpin to produce
the derived LnCu-SiMe2Ph I, which can undergo asymmetric
conjugate addition reaction with alkenyl-substituted quinoline
1a to obtain intermediate III through transition state II. The
resulting aza-π-allylcopper intermediate III reacts with
methanol to afford the desired product 2a and regenerate the
active copper catalysts for the next catalytic cycle.
3
4
For selected recent reviews, see: (a) G. J. Reyes-Rodríguez, N.
M. Rezayee, A. Vidal-Albalat and K. A. Jørgensen, Chem. Rev.,
2019, 119, 4221; (b) L. Wu, J. Shen, G. Yang and W. Zhang,
Tetrahedron Lett., 2018, 59, 4055; (c) K. Zheng, X. Liu and X.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 4 of 5
COMMUNICATION
Journal Name
Feng, Chem. Rev., 2018, 118, 7586; (d) T. Jia, P. Cao and J. Liao,
Chem. Sci., 2018, 9, 546; (e) B. Mao, M. Fañanás-Mastral and
B. L. Feringa, Chem. Rev., 2017, 117, 10502; (f) C. Hui, F. Pu
14758; (j) B.-C. Da, Q.-J. Liang, Y.-C. Luo, T. Ahmad, Y.-H. Xu
Xie, Y.-H. Xu and T.-P. Loh, ACS Catal., D2O01I:81,08.1,05393/0C69.CC08910A
View Article Online
and T.-P. Loh, ACS Catal., 2018, 8, 6239; (k) F.-F. Meng, J.-H.
and J. Xu, Chem. Eur. J., 2017, 23, 4023; (g) M. Hayashi and R. 18 For screening of bases, additives and copper salts, see the
Matsubara, Tetrahedron Lett., 2017, 58, 1793; (h) T. N. Supporting Information.
Nguyen and J. A. May, Tetrahedron Lett., 2017, 58, 1535; (i) A. 19 CCDC 1955733 (2b) contains the supplementary
Mondal, S. Bhowmick, A. Ghosh, T. Chanda and K. C.
Bhowmick, Tetrahedron: Asymmetry, 2017, 28, 849; (j) D. A.
Alonso, A. Baeza, R. Chinchilla, C. Gómez, G. Guillena, I. M.
crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Pastor and D. J. Ramón, Molecules, 2017, 22, 895; (k) M. M. 20 R. Shintani, K. Okamoto and T. Hayashi, Org. Lett., 2005, 7,
Heravi, M. Dehghani and V. Zadsirjan,
Tetrahedron:
4757.
Asymmetry, 2016, 27, 513.
5
6
Reviews: (a) J. R. Wilkinson, C. E. Nuyen, T. S. Carpenter, S. R.
Harruff and R. Van Hoveln, ACS Catal., 2019, 9, 8961; (b) S.
Bähr, W. Xue and M. Oestreich, ACS Catal., 2019, 9, 16; (c) M.
Suginome and Y. Ito, Chem. Rev., 2000, 100, 3221.
(a) D. J. Ager and I. Fleming, J. Chem. Soc., Chem. Commun.,
1978, 177; (b) K. Tamao, N. Ishida, T. Tanaka and M. Kumada,
Organometallics, 1983, 2, 1694; (c) I. Fleming, R. Henning and
H. Plaut, J. Chem. Soc., Chem. Commun., 1984, 29; (d) K.
Tamao, T. Tanaka, T. Nakajima, R. Sumiya, H. Arai and Y. Ito,
Tetrahedron Lett., 1986, 27, 3377; (e) I. Fleming and P. E. J.
Sanderson, Tetrahedron Lett., 1987, 28, 4229; For selected
reviews, see: (f) I. Fleming, A. Barbero and D. Walter, Chem.
Rev., 1997, 97, 2063; (g) I. Fleming, In Science of Synthesis; I.
Fleming, Ed.; Thieme: Stuttgart, 2002; Vol. 4; pp 927−946.
(a) L.-W. Xu, L. Li, G.-Q. Lai and J.-X. Jiang, Chem. Soc. Rev.,
2011, 40, 1777; (b) T. Komiyama, Y. Minami and T. Hiyama,
ACS Catal., 2017, 7, 631.
7
8
9
T. Hayashi, Y. Matsumoto and Y. Ito, J. Am. Chem. Soc., 1988,
110, 5579.
(a) C. Walter, G. Auer and M. Oestreich, Angew. Chem. Int.
Ed., 2006, 45, 5675; (b) C. Walter and M. Oestreich, Angew.
Chem. Int. Ed., 2008, 47, 3818; (c) E. Hartmann and M.
Oestreich, Angew. Chem. Int. Ed., 2010, 49, 6195; (d) E.
Hartmann and M. Oestreich, Org. Lett., 2012, 14, 2406.
10 (a) K.-s. Lee and A. H. Hoveyda, J. Am. Chem. Soc., 2010, 132,
2898; (b) J. M. O’Brien and A. H. Hoveyda, J. Am. Chem. Soc.,
2011, 133, 7712; (c) K.-s. Lee, H. Wu, F. Haeffner and A. H.
Hoveyda, Organometallics, 2012, 31, 7823.
11 I. Ibrahem, S. Santoro, F. Himo and A. Córdova, Adv. Synth.
Catal., 2011, 353, 245.
12 (a) V. Pace, J. P. Rae, H. Y. Harb and D. J. Procter, Chem.
Commun., 2013, 49, 5150; (b) V. Pace, J. P. Rae and D. J.
Procter, Org. Lett., 2014, 16, 476.
13 T. Kitanosono, L. Zhu, C. Liu, P. Xu and S. Kobayashi, J. Am.
Chem. Soc., 2015, 137, 15422.
14 W. Mao, W. Xue, E. Irran and M. Oestreich, Angew. Chem. Int.
Ed., 2019, 58, 10723.
15 (a) W. Xue, R. Shishido and M. Oestreich, Angew. Chem. Int.
Ed., 2018, 57, 12141; (b) W. Xue and M. Oestreich, Synthesis,
2019, 51, 233; (c) H. Yi and M. Oestreich, Chem. Eur. J., 2019,
25, 6505.
16 M. Suginome, H. Nakamura and Y. Ito, Chem. Commun., 1996,
2777.
17 For reviews on the utility of silylborane reagents in chemical
synthesis, see: (a) T. Ohmura and M. Suginome, Bull. Chem.
Soc. Jpn., 2009, 82, 29; (b) E. Hartmann and M. Oestreich,
Chim. Oggi, 2011, 29, 34; (c) E. Hartmann, D. J. Vyas and M.
Oestreich, Chem. Commun., 2011, 47, 7917; (d) M. Oestreich,
E. Hartmann and M. Mewald, Chem. Rev., 2013, 113, 402, and
recent asymmetric examples see: (e) Z.-L. Liu, C. Yang, Q.-Y.
Xue, M. Zhao, C.-C. Shan, Y.-H. Xu and T. Loh, Angew.Chem.
Int. Ed., 2019, 58,16538; (f) C.-Y. He, L.-B. Xie, R. Ding, P. Tian
and G.-Q. Lin, Tetrahedron, 2019, 75, 1682; (g) L. Zhang and
M. Oestreich, Chem. Eur. J., 2019, 25, 14304; (h) K. Yabushita,
A. Yuasa, K. Nagao and H. Ohmiya, J. Am. Chem. Soc., 2019,
141, 113; (i) Y. Shi, Q. Gao and S. Xu, J. Org. Chem., 2018, 83,
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 5
ChemComm
View Article Online
DOI: 10.1039/C9CC08910A
L*
Cu(MeCN)4PF6/
O
O
N
Ar
N
Ar
PhMe2SiBPin, NaOtBu
MeOH, THF, rt
P
N
O
X
X
SiMe2Ph
L*
Quinoline
good yields and scalable
Isoquinoline
Benzoxazole
Benzothiazole
excellent stereoselectivities
operationally simple, at room temperature
easily accessible chiral phosphoramidite ligands and silylating agents
Asymmetric conjugate addition of PhMe2SiBPin to a wide range of N-heteroaryl alkenes proceeded
in the presence of a copper catalyst coordinated with an easily accessible chiral phosphoramidite
ligand to afford useful β-silyl N-heteroarenes in high yields and ees.