Cu/Mn bimetallic catalysis enables carbonylative Suzuki-Miyaura coupling with unactivated alkyl electrophiles

Article abstract of DOI:10.1039/c7sc01170a

A bimetallic system consisting of Cu-carbene and Mn-carbonyl co-catalysts was employed for carbonylative C-C coupling of arylboronic esters with alkyl halides, allowing for the convergent synthesis of ketones. The system operates under mild conditions and exhibits complementary reactivity to Pd catalysis. The method is compatible with a wide range of arylboronic ester nucleophiles and proceeds smoothly for both primary and secondary alkyl iodide electrophiles. Preliminary mechanistic experiments corroborate a hypothetical catalytic mechanism consisting of co-dependent cycles wherein the Cu-carbene co-catalyst engages in transmetallation to generate an organocopper nucleophile, while the Mn-carbonyl co-catalyst activates the alkyl halide electrophile by single-electron transfer and then undergoes reversible carbonylation to generate an acylmanganese electrophile. The two cycles then intersect with a heterobimetallic, product-releasing C-C coupling step.

Full text of DOI:10.1039/c7sc01170a

View Article Online
View Journal
Chemical
Science
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: D. R. Pye, L.
Cheng and N. Mankad, Chem. Sci., 2017, DOI: 10.1039/C7SC01170A.
This is an Accepted Manuscript, which has been through the
Volume
7 Number 1 January 2016 Pages 1–812
Royal Society of Chemistry peer review process and has been
accepted for publication.
Chemical
Science
Accepted Manuscripts are published online shortly after
www.rsc.org/chemicalscience
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
author guidelines.
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, outlined
in our author and reviewer resource centre, 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 2041-6539
EDGE ARTICLE
Francesco Ricci et al.
Electronic control of DNA-based nanoswitches and nanodevices
rsc.li/chemical-science

Please do not adjust margins
Chemical Science
Page 1 of 5
View Article Online
DOI: 10.1039/C7SC01170A
Journal Name
ARTICLE
Cu/Mn Bimetallic Catalysis Enables Carbonylative Suzuki-Miyaura
Coupling with Unactivated Alkyl Electrophiles
Received 00th January 20xx,
Accepted 00th January 20xx
Dominic R. Pye, Li-Jie Cheng and Neal P. Mankad*
A bimetallic system consisting of Cu-carbene and Mn-carbonyl co-catalysts was employed for carbonylative C-C coupling of
arylboronic esters with alkyl halides, allowing for the convergent synthesis of ketones. The system operates under mild
conditions and exhibits complementary reactivity to Pd catalysis. The method is compatible with a wide range of
arylboronic ester nucleophiles and proceeds smoothly for both primary and secondary alkyl iodide electrophiles.
Preliminary mechanistic experiments corroborate a hypothetical catalytic mechanism consisting of co-dependent cycles
wherein the Cu-carbene co-catalyst engages in transmetallation to generate an organocopper nucleophile, while the Mn-
carbonyl co-catalyst activates the alkyl halide electrophile by single-electron transfer and then undergoes reversible
carbonylation to generate an acylmanganese electrophile. The two cycles then intersect with a heterobimetallic, product-
DOI: 10.1039/x0xx00000x
www.rsc.org/
releasing
C-C
coupling
step.
Introduction
Ketones are ubiquitous functional groups in organic molecules
and materials, and furthermore their established reaction
chemistry can be used to introduce other heteroatom-containing
functional groups at late stages of complex syntheses.
A
convergent method for constructing ketones from simple building
blocks is Pd-catalyzed carbonylative C-C coupling, such as the
carbonylative Suzuki-Miyaura, Mizoroki-Heck, and Sonogashira
coupling reactions.1-3 These Pd-catalyzed carbonylations have
been long established for C(sp2)-hybridized electrophiles, i.e. aryl
and vinyl halides (Figure 1a). The use of C(sp3)-hybridized
electrophiles, i.e. alkyl halides, has been reported for specialized
cases lacking β-hydrogens,4-9 but cases involving alkylpalladium
intermediates susceptible to β-hydride elimination have been
more challenging to solve.10-12 Ryu recently reported a Pd-
catalyzed method that solves this problem in a general way but
requires irradiation with a Xe lamp to generate alkyl radicals that
undergo carbonylation at high pressure (45 atm).13 Non-
carbonylative Pd-catalyzed reactions to generate alkyl-substituted
ketones involve arylcarboxylic acid derivatives as electrophiles14
and include the Liebeskind-Srogl15 and Fukuyama16 coupling
reactions. Both carbonylative17,18 and non-carbonylative19 Ni-
catalyzed reductive coupling reactions to generate alkyl-
substituted ketones also have been reported.
Figure 1. Previous work on (a) Pd-catalyzed Suzuki-Miyaura and (b) base metal-
catalyzed heterocarbonylation reactions; (c) this work on base metal-catalyzed
carbonylative C-C coupling with alkyl iodides.
Base metal carbonylate complexes are efficient catalysts for
heterocarbonylation reactions of alkyl halides. Heck and Breslow
first reported the use of Na[Co(CO)4] as a catalyst for the
formation of esters from alkyl halides, CO, and alcohols over 50
years ago.20 Since then, the formation of esters and amides via
carbonylation of alkyl halides in the presence of an appropriate
nucleophile, i.e. an alcohol or amine, has been studied using both
Co- and Mn-carbonyl pre-catalysts (Figure 1b).21,22 Coates has
extended this chemistry to include epoxide carbonylation using a
bifunctional catalysis approach.23,24 There has not, however, been
a
suitable carbon nucleophile identified to participate in
carbonylative C-C coupling chemistry to form ketones within such
systems. Many carbon nucleophiles, such as Grignard reagents,
that would be sufficiently nucleophilic to participate in the desired
catalytic C-C coupling processes would also react with the ketone
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
Chemical Science
Page 2 of 5
View Article Online
DOI: 10.1039/C7SC01170A
ARTICLE
Journal Name
products, thus destroying the target molecules. Organocopper the Mn co-catalyst from the reaction (Entries 6-7), thus verifying
nucleophiles are used extensively for 1,4-addition to α,β- the need for bimetallic catalysis. With regard to the nucleophilic
unsaturated ketones due to their resistance towards 1,2-addition coupling partner, efficient reactivity also was observed using the
to carbonyl groups.25 Thus, we hypothesized that
a
pinacol ester (1b) rather than 1a, while poor reactivity was
heterobimetallic system consisting of organocopper intermediates observed with the unprotected boronic acid (1c) (Entries 8-9).
in combination with Co or Mn carbonylates would enable
carbonylative C-C coupling with alkyl halides to generate ketones,
Table 1. Optimization of Cu/Mn-catalyzed carbonylative C-C coupling.
without then consuming the resulting ketone products (Figure 1c).
Our hypothetical mechanism for a carbonylative Suzuki-Miyaura
reaction, then, consists of a Heck-Breslow cycle for alkyl halide
carbonylation combined with a Cu cycle that generates catalytic
quantities of an arylcopper species from a mild arylboronic ester
nucleophile (Scheme 1). The two co-dependent cycles intersect
with a heterobimetallic C-C coupling step between an arylcopper
nucleophile and
a metal-acyl electrophile. This mechanistic
paradigm represents a new frontier in bimetallic catalysis for C-C
coupling,26 which otherwise typically involves catalytic generation
of an organometallic nucleophile that undergoes transmetallation
with a catalytically generated Pd(II) electrophile,27-34 thus still
requiring use of Pd catalysis and its inherent limitations.
Entry
1a
2a
3
B(OR)2
X
Cu
catalyst
10%
Mn catalyst
Yield of
3 (%)
40b
Bneop
(1a)
I (2a)
10%
Na[Mn(CO)5]
10%
(IPr)CuCl
Bneop
(1a)
I (2a)
10%
45b
59b
73b
(ClIPr)CuCl Na[Mn(CO)5]
Bneop
(1a)
I (2a)
10%
10%
(ClIPr)CuCl Na[Mn(CO)5]
4
Bneop
(1a)
I (2a)
10%
(IPr)CuCl
15%
10%
Na[Mn(CO)5]
7.5%
5
Bneop
(1a)
I (2a)
88b
(70)c
5b
(IPr)CuCl
15%
Na[Mn(CO)5]
none
6
Bneop
(1a)
I (2a)
Scheme 1. Bimetallic mechanism for carbonylative Suzuki-Miyaura coupling.
(IPr)CuCl
none
7
Bneop
(1a)
I (2a)
7.5%
Na[Mn(CO)5]
7.5%
0b
8
Bpin
I (2a)
15%
(IPr)CuCl
15%
69c
42c
13c
66c
0c
Results and Discussion
(1b)
Na[Mn(CO)5]
7.5%
As a starting point, we investigated the reaction of 4-tolylboronic
acid neopentyl glycol ester (1a) and 1-iodooctane (2a) under an
atmosphere of carbon monoxide. Initial experimentation indicated
that the desired ketone (3) formed in 40% yield in THF solvent at
60°C in the presence of KOMe base (1.5 equiv) and catalytic
amounts (10 mol%) of (IPr)CuCl and Na[Mn(CO)5] (Table 1, Entry
1). Lower yields were obtained with bulkier alkoxide bases or with
tricyclohexylphosphine in place of the IPr carbene. The same
result was obtained by using catalytic (IPr)Cu-Mn(CO)5, which is
expected to assemble upon mixing the Cu and Mn co-catalysts,35
and so optimization was continued using separate pre-catalysts
rather than with Cu/Mn-bonded heterobimetallic complexes.
Substituting IPr for ClIPr gave a slight increase in yield of 3 to
45%, and performing the reaction under modestly higher CO
pressure (3 atm) raised the yield to 59% (Entries 2-3). A screen of
numerous copper-carbene co-catalysts at this pressure (see
Supplementary Materials) identified a number that gave yields in
the 70-75% range, and so we continued with commercially
available and easily synthesized (IPr)CuCl (Entry 4). Altering the
pre-catalyst loadings to 15% (IPr)CuCl and 7.5% Na[Mn(CO)5]
was found empirically to increase yield of 3 to 88% (Entry 5). No
catalysis was observed when omitting either the Cu co-catalyst or
9
B(OH)2
(1c)
I (2a)
(IPr)CuCl
15%
Na[Mn(CO)5]
7.5%
10
11d
12
13d
14
Bneop
(1a)
Br (2b)
Br (2b)
OTs (2c)
OTs (2c)
I (2a)
(IPr)CuCl
15%
Na[Mn(CO)5]
7.5%
Bneop
(1a)
(IPr)CuCl
15%
Na[Mn(CO)5]
7.5%
Bneop
(1a)
(IPr)CuCl
15%
Na[Mn(CO)5]
7.5%
Bneop
(1a)
74c
56c
(IPr)CuCl
15%
Na[Mn(CO)5]
3.8%
Bneop
(1a)
(IPr)CuCl
Mn2(CO)10
apCO = 1 atm. bYield determined by NMR analysis (1,3,5-trimethoxybenzene
internal standard). cYield determined by GC analysis (decane internal standard).
dadditive = Bu4N+I-.
Ketone 3 did not form in high yield when 1-bromooctane (2b)
or 1-octyltosylate (2c) were used in place of 2a, but reactivity was
restored when these reactions were run in the presence of
stoichiometric tetrabutylammonium iodide, presumably via the in-
situ formation of 2a (Entries 10-13). Lastly, ketone 3 was formed
with only slightly compromised yield when using 0.5 Mn2(CO)10 in
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Chemical Science
Page 3 of 5
View Article Online
DOI: 10.1039/C7SC01170A
Journal Name
ARTICLE
place of Na[Mn(CO)5] (Entry 14). This result is noteworthy for the did not have measureable impact on the formation of 3 and was
use of (IPr)CuCl and Mn2(CO)10 co-catalysts, both of which are inert under the reaction conditions. This observation is particularly
commercially available and stable to air and moisture. We verified noteworthy, as typical Pd catalysts would readily activate C(sp2)-
that no non-carbonylative Suzuki-Miyaura (alkylated arene), Heck- Br bonds. Only mild poisoning was observed with protic additives
Breslow (ester), or Williamson (ether) products were formed in such as alcohols and terminal alkynes. Pyridine and N-methyl
these reactions. Rather, the mass balance consists of unidentified benzamide were the only additives definitively not tolerated in this
decomposition products.
robustness screen because they inhibited the reaction or were
unstable under the conditions, respectively. Collectively, these
results demonstrate that the Cu/Mn-catalyzed carbonylative
coupling reaction is ideal both for late-stage functionalization and
for the synthesis of ketones bearing latent synthetic handles
useful for further elaboration, with only a small number of
exceptions. It is noteworthy that many of the functional groups
tolerated here would be incompatible with traditional Friedel-
Crafts acylation conditions.
Figure 3. Reaction sequences demonstrating (a) orthogonality of Cu/Mn catalysis and
Pd catalysis; (b) relevance of Cu/Mn catalysis to heterocycle synthesis. Cu/Mn
conditions: Catalytic conditions: alkyl iodide (0.2 mmol), arylboronic ester (1.5 eq),
KOMe (1.5 eq), (IPr)CuCl (15 mol%), Na[Mn(CO)5] (7.5 mol%), THF (5 mL), CO (3 atm),
60°C, 15 h. Pd conditions: aryl bromide (0.5 mmol), arylboronic acid (2.0 eq), K2CO3 (2.0
eq), PdCl2(PPh3)2 (10 mol%), toluene:H2O (10:1, 5.5 mL), 100°C, 21 h. Reductive
amination conditions: (i) CF3CO2H (0.5 mL), CH2Cl2 (3 mL), 0°C, 2 h, (ii) NaBH4 (4 eq),
MeOH (5 mL),
1
h. aIsolated yield. bYield determined by NMR analysis (1,3,5-
trimethoxybenzene internal standard).
Guided by the results of the robustness screen, we next
conducted substrate scope studies to examine steric and electron
constraints on the coupling mechanism (Figure 2). Electron-rich,
electron-poor, and sterically encumbered arylboronic esters
underwent carbonylative coupling with 2a efficiently to generate
ketones 3-13 in moderate to high yields. It is noteworthy that
several of these ketones represent aromatic regioisomers that
would be unavailable by Friedel-Crafts acylation. A secondary
alkyl iodide, iodocyclohexane, underwent carbonylative coupling
with 1a in only 10% yield under the optimized conditions. We
reasoned that formation of cyclohexyl-substituted ketone 13 may
be slow due to the relevant secondary manganese-acyl
Figure 2. Substrate scope of Cu/Mn-catalyzed carbonylative Suzuki-Miyaura coupling.
Yields determined by product isolation unless otherwise indicated. aGC yield (decane
internal standard). bFrom arylboronic acid pinacol ester. cIsolated as 2:1 mixture with
N,N-dimethylbenzamide.
In order to investigate functional group compatibility relevant
to the synthesis of complex and functionally dense ketone
products, we used the carbonylative formation of 3 to conduct a intermediate being more sterically hindered, and therefore less
Glorius robustness screen.36 The formation of 3 was found to be
electrophilic, than the corresponding primary intermediate derived
from 2a. Using the smaller and more electron-donating ItBu in
place of IPr provided 14 in excellent yield. Under these conditions,
ketone 15, which is a synthetic precursor to a glucagon receptor
modulator marketed by Pfizer,37 also was synthesized in high
yield. Acyclic secondary alkyl iodides also reacted smoothly,
allowing for the isolation of ketones 16 and 17. The formation of
robust towards a remarkable range of remote functional groups
(Figure S1). Strongly electrophilic groups such as aldehydes,
esters, and nitriles are tolerated, demonstrating the judicious
choice of organocopper nucleophiles in this system. Nucleophilic
groups such as a sulfur heterocycle and an unprotected primary
amine also were tolerated. Intriguingly, an aryl bromide additive
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
Chemical Science
Page 4 of 5
View Article Online
DOI: 10.1039/C7SC01170A
ARTICLE
Journal Name
chiral 17 opens the opportunity for future development of
asymmetric catalysis for the enantioselective formation of ketones
with α-stereocenters, a possibility that would be challenging for
Pd-catalyzed carbonylation. Ketones derived from benzyl or allyl
electrophiles were not observed, presumably due to their
instability under the basic reaction conditions. Another limitation of
the method is that ketones derived from vinyl- or alkynylboronic
esters were not observed, presumably because they are
susceptible to conjugate addition under the reaction conditions.
Lastly, various heteroarylboronic ester nucleophiles that we
examined did not undergo productive carbonylative coupling with
2a.
To leverage the assets of our method, we sought both to
synthesize ketones bearing synthetic handles for further
elaboration and to construct ketones that can serve as synthons
for privileged structures relevant to drug molecules. First, to
demonstrate the orthogonality of Cu/Mn catalysis and Pd
catalysis, we conducted the Cu/Mn-catalyzed carbonylative
coupling reaction with an arylboronic ester nucleophile containing
an aryl-bromide linkage that would be unstable under Pd-
catalyzed conditions (Figure 3a). Isolation of the resulting ketone
18 proceeded smoothly without activation of the C(sp2)-Br
position. Further elaboration at that position was then
demonstrated through its use as the electrophilic component of a
traditional Pd-catalyzed Suzuki-Miyaura coupling reaction, which
provided the 4-biphenyl ketone 19 quantitatively. Second, to
demonstrate utility towards the synthesis of drug molecules, we
conducted the Cu/Mn-catalyzed carbonylative coupling with 3-
aminoalkyl iodide 20, which provided the 3-aminoalkyl ketone 21
(Figure 3b). Subjecting a crude sample of 21 to standard N-Boc
deprotection and reductive amination conditions provided the 2-
arylpyrrolidine product 22 in 57% yield from 20. The C(sp3)-C(sp2)
linkage α to the nitrogen in 22 was installed by Cu/Mn-catalyzed
C-C coupling. Pyrrolidines and related C(sp3)-rich heterocycles
are known to be privileged core structures in drug molecule
candidates, and the installation of aromatic substituents in the
position α to the heteroatom in such structures by coupling
methods is a longstanding challenge actively being pursued by
several research groups.38-42 Here, the construction of such a
motif is enabled by the unique reactivity of the Cu/Mn-catalyzed
coupling reaction towards C(sp3)-hybridized substrates.
Figure 4. Reactivity studies to probe the catalytic mechanism. Yields determined by
NMR analysis (1,3,5-trimethoxybenzene internal standard). Catalytic conditions: alkyl
iodide (0.2 mmol), arylboronic ester (1.5 eq), KOMe (1.5 eq), (IPr)CuCl (15 mol%),
Na[Mn(CO)5] (7.5 mol%), THF (5 mL), CO (3 atm), 60°C, 15 h.
Lastly, we sought to probe the viability of our hypothetical
mechanism through stoichiometric reactivity studies. First,
because (IPr)Cu-Mn(CO)5 is expected to assemble upon mixing
(IPr)CuCl and Na[Mn(CO)5],35 we sought to establish its role in the
bimetallic catalysis (Figure 4a). The metal-metal bonded complex
(IPr)Cu-Mn(CO)5 was found to be unreactive towards 2a in THF at
60°C. On the other hand, exposing this metal-metal bonded
complex to NaOtBu and 1a under the same conditions led to a
mixture of (IPr)CuOtBu, (IPr)Cu(tol) (tol = p-tolyl), and presumably
Na[Mn(CO)5]. Based on these observations, we propose that the
metal-metal bonded complex (IPr)Cu-Mn(CO)5 is not an on-cycle
catalytic intermediate capable of activating any of the coupling
partners directly, but rather it is unstable under the basic
conditions of catalysis towards formation of (IPr)CuOMe and the
“unmasked” K[Mn(CO)5]. Alkylation of [Mn(CO)5]- by iodoalkanes
is well known20 and is thought to proceed by a single-electron
transfer mechanism.21,22 Consistent with this proposal, we
observed radical cyclization/ring-opening behavior with the radical
clock iodoalkanes 23 and 24 (Figure 4b). Lastly, the ketone-
generating, bimetallic C-C coupling step between the arylcopper
and acylmanganese intermediates has no precedent in the
literature. In order to establish feasibility of this mechanistically
novel C-C coupling step, we examined reactivity between isolated
samples of (IPr)Cu(tol) and MeC(O)Mn(CO)5 (Figure 4c). When
the experiment was conducted in THF at 60°C under N2
atmosphere, no 4-methylacetophenone (25) was observed.
However, when the same reaction was conducted under an
atmosphere of CO (3 atm), the expected ketone product 25 was
formed in 67% yield. These results are consistent with the
product-releasing C-C bond formation being viable but having to
compete with de-insertion of CO, thus requiring the application of
CO pressure. This stoichiometric C-C coupling reaction
demonstrates the key role of a novel heterobimetallic C-C bond-
forming step in the catalytic generation of ketones.
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Chemical Science
Page 5 of 5
View Article Online
DOI: 10.1039/C7SC01170A
Journal Name
ARTICLE
22
23
C. M. McMahon, M. S. Renn and E. J. Alexanian, Org. Lett.,
2016, 18, 4148–4150.
J. A. R. Schmidt, E. B. Lobkovsky and G. W. Coates, J. Am.
Chem. Soc., 2005, 127, 11426–11435.
Conclusions
Bimetallic catalysis with earth-abundant Cu and Mn was
leveraged to discover C-C coupling chemistry that
complements existing methods with single-site Pd catalysis. 24
Conceptually, the bimetallic scheme is novel in the context of
M. Mulzer, B. T. Whiting and G. W. Coates, J. Am. Chem. Soc.,
2013, 135, 10930–10933.
25
M. S. Kharasch and P. O. Tawney, J. Am. Chem. Soc., 1941, 63,
2308–2316.
D. R. Pye and N. P. Mankad, Chemical Science, 2017, 8, 1705–
1718.
K. Sonogashira, J. Organomet. Chem., 2002, 653, 46–49.
L. K. G. Ackerman, M. M. Lovell and D. J. Weix, Nature, 2015,
524, 454–457.
S. D. Friis, M. T. Pirnot and S. L. Buchwald, J. Am. Chem. Soc.,
2016, 138, 8372–8375.
P. García-Domínguez and C. Nevado, J. Am. Chem. Soc., 2016,
138, 3266–3269.
J. J. Hirner, Y. Shi and S. A. Blum, Acc. Chem. Res., 2011, 44,
603–613.
K. Semba and Y. Nakao, J. Am. Chem. Soc., 2014, 136, 7567–
7570.
Y. Zhou, W. You, K. B. Smith and M. K. Brown, Angew. Chem.
Int. Ed., 2014, 53, 3475–3479.
transformations featuring two co-dependent catalytic metals
in that it does not utilize Pd. A limitation of Pd catalysis,
namely the inability to efficiently carbonylate C(sp3)-hybridized
electrophiles, was thus overcome.
26
27
28
Acknowledgements
29
30
31
32
33
34
35
Funding was provided by the NSF (CHE-1362294) and the ACS
Green Chemistry Institute (Pharmaceutical Roundtable Grant).
N.P.M. is an Alfred P. Sloan Research Fellow. Prof. Justin Mohr
provided access to a GC.
Notes and references
1
A. Brennführer, H. Neumann and M. Beller, Angew. Chem.
Int. Ed., 2009, 48, 4114–4133.
M. H. Pérez-Temprano, J. A. Casares and P. Espinet, Chem.
Eur. J., 2012, 18, 1864–1884.
2
X.-F. Wu, H. Neumann and M. Beller, Chem. Soc. Rev., 2011,
40, 4986–5009.
S. Banerjee, M. K. Karunananda, S. Bagherzadeh, U.
Jayarathne, S. R. Parmelee, G. W. Waldhart and N. P.
Mankad, Inorg. Chem., 2014, 53, 11307–11315.
K. D. Collins and F. Glorius, Nat. Chem., 2013, 5, 597–601.
B. J. Simmons, N. A. Weires, J. E. Dander and N. K. Garg, ACS
Catal., 2016, 6, 3176–3179.
3
4
C. F. J. Barnard, Organometallics, 2008, 27, 5402–5422.
F. Garrido, S. Raeppel, A. Mann and M. Lautens, Tetrahedron
Letters, 2001, 42, 265–266.
36
37
5
R. F. W. Jackson, D. Turner and M. H. Block, J. Chem. Soc.,
Chem. Commun., 1995, 2207–2208.
6
M. Medio-Simón, C. Mollar, N. Rodríguez and G. Asensio,
Org. Lett., 2005, 7, 4669–4672.
J. Sävmarker, J. Lindh and P. Nilsson, Tetrahedron Letters,
2010, 51, 6886–6889.
Y. Wakita, T. Yasunaga, M. Akita and M. Kojima, J.
Organomet. Chem., 1986, 301, C17–C20.
X.-F. Wu, H. Neumann and M. Beller, Tetrahedron Letters,
2010, 51, 6146–6149.
T. Ishiyama, N. Miyaura and A. Suzuki, Tetrahedron Letters,
1991, 32, 6923–6926.
38
39
40
Z. Zuo, D. T. Ahneman, L. Chu, J. A. Terrett, A. G. Doyle and D.
W. C. MacMillan, Science, 2014, 345, 437–440.
J. E. Spangler, Y. Kobayashi, P. Verma, D.-H. Wang and J.-Q.
Yu, J. Am. Chem. Soc., 2015, 137, 11876–11879.
J. Cornella, J. T. Edwards, T. Qin, S. Kawamura, J. Wang, C.-M.
Pan, R. Gianatassio, M. Schmidt, M. D. Eastgate and P. S.
Baran J. Am. Chem. Soc., 2016, 138, 2174–2177.
M. H. Shaw, V. W. Shurtleff, J. A. Terrett, J. D. Cuthbertson
and D. W. C. MacMillan, Science, 2016, 352, 1304–1308.
K. M. M. Huihui, J. A. Caputo, Z. Melchor, A. M. Olivares, A.
M. Spiewak, K. A. Johnson, T. A. DiBenedetto, S. Kim, L. K. G.
Ackerman and D. J. Weix, J. Am. Chem. Soc., 2016, 138,
5016–5019.
7
8
9
41
42
10
11
12
Y. Tamaru, H. Ochiai, Y. Yamada and Z. Yoshida, Tetrahedron
Letters, 1983, 24, 3869–3872.
T. Kondo, Y. Tsuji and Y. Watanabe, J Organomet Chem, 1988,
345, 397–403.
13
14
S. Sumino, T. Ui and I. Ryu, Org. Lett., 2013, 15, 3142–3145.
L. J. Goossen and K. Ghosh, Angew. Chem. Int. Ed., 2001, 40,
3458–3460.
15
16
17
18
19
20
21
L. S. Liebeskind and J. Srogl, J. Am. Chem. Soc., 2000, 122,
11260–11261.
H. Tokuyama, S. Yokoshima, T. Yamashita and T. Fukuyama,
Tetrahedron Letters, 1998, 39, 3189–3192.
A. C. Wotal, R. D. Ribson and D. J. Weix, Organometallics,
2014, 33, 5874–5881.
M. Oçafrain, M. Devaud, M. Troupel and J. Périchon, J. Chem.
Soc., Chem. Commun., 1995, 2331–2332.
C. Zhao, X. Jia, X. Wang and H. Gong, J. Am. Chem. Soc., 2014,
136, 17645–17651.
R. F. Heck and D. S. Breslow, J. Am. Chem. Soc., 1963, 85,
2779–2782.
T. Kondo, Y. Sone, Y. Tsuji and Y. Watanabe, J. Organomet.
Chem., 1994, 473, 163–173.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins