Alkylammoniotrifluoroborate functionalized polystyrenes: Polymeric pre-catalysts for the metal-free borylation of heteroarenes

Article abstract of DOI:10.1039/c9dt00484j

Three polymeric versions of ansa-N,N-dialkylammoniumtrifluoroborate ambiphilic molecules based on the styrene motif (poly(1-NMe₂H⁺-2-BF₃^--4-styrene) (P-Me), poly(1-NEt₂H⁺-2-BF₃^--4-styrene) (P-Et) and poly(1-piperidinyl-H⁺-2-BF₃^--4-styrene) (P-Pip)) were synthesized, characterized and tested as heterogeneous pre-catalysts for the borylation of electron-rich heteroarenes. These heterogeneous versions of previously reported pre-catalysts show similar reactivity patterns and represent the first examples of solid-supported FLP metal-free catalysts for the C-H borylation of heteroarenes.

Full text of DOI:10.1039/c9dt00484j

View Article Online
View Journal
Dalton
Transactions
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: N. Bouchard and
F. Fontaine, Dalton Trans., 2019, DOI: 10.1039/C9DT00484J.
This is an Accepted Manuscript, which has been through the
Volume 45 Number
1 7 January 2016 Pages 1–398
Royal Society of Chemistry peer review process and has been
accepted for publication.
Dalton
Transactions
Accepted Manuscripts are published online shortly after
An international journal of inorganic chemistry
www.rsc.org/dalton
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 1477-9226
PAPER
Joseph T. Hupp, Omar K. Farha et al.
Efficient extraction of sulfate from water using
framework
a Zr-metal–organic
rsc.li/dalton

Page 1 of 12
PleasDeadltoonnoTtraandsjaucsttiomnsargins
View Article Online
DOI: 10.1039/C9DT00484J
Dalton Transactions
ARTICLE
borylation reaction with arenes or aryl halides use noble
metals14,15 such as iridium,16–19 platinum,20,21 rhodium22,23 and
palladium.24–27 In recent years, first row transition metals have
also been shown to catalyse these transformations with high
efficiency following elegant ligand design.28–33
Received 00th January 20xx,
Accepted 00th January 20xx
Metal-free catalysis has been thriving in the past decade, driven
by the desire for greener, cheaper and less toxic catalysts.34 As
such, our group reported recently the use of ambiphilic
aminoborane molecules as catalysts for the C-H borylation of
heteroarenes.35–39 Using the concept of frustrated Lewis pair
(FLP) chemistry,40–44 these organic molecules rely on the
cooperation between donor and acceptor groups to activate
the C-H bonds of electron-rich heteroarenes. Typically, the
selectivity observed is similar to the one traditionally seen in
electrophilic borylation transformations.13 Since our first report,
several contributions have demonstrated the generality of the
C-H activation process45–54 and several new transition metal-
free catalytic systems have been developed for the borylation
reaction.52–54 It was later shown by our group that air stable
ansa-ammoniotrifluoroborate zwitterions A-D (Fig 1) could be
activated by HBpin upon catalytic conditions to generate
DOI: 10.1039/x0xx00000x
www.rsc.org/
Alkylammoniotrifluoroborate
functionalized polystyrenes: polymeric
pre-catalysts for the metal-free
borylation of heteroarenes
Nicolas Boucharda and Frédéric-Georges Fontainea,b
*
Three polymeric versions of ansa-N,N-dialkylammoniumtrifluoroborate
ambiphilic molecules based on the styrene motif (poly(1-NMe2H+-2-BF3 -4-
-
-
styrene) (P-Me),
poly(1-NEt2H+-2-BF3 -4-styrene) (P-Et) and poly(1-
-
piperidinyl-H+-2-BF3 -4-styrene) (P-Pip)) were synthesized, characterized and
tested as heterogeneous precatalysts for the borylation of electron-rich
heteroarenes. These heterogeneous versions of previously reported pr-
catalysts show similar reactivity patterns and represent the first examples of
solid-supported FLP metal-free catalysts for the C-H borylation of
heteroarenes.
respective ansa-aminohydroborane catalysts with the loss of H2
37,55
and FBpin (pin = pinacol)
.
The easy synthesis and
manipulation under air of these borylation pre-catalysts
allowed the scaling up of the reactions up to the kilogram.38
Introduction
Modern synthetic methodologies for the preparation of
pharmaceuticals and modern materials rely heavily on
arylboronates.1 These precursors are notably used in the
Suzuki-Miyaura2 and Chan-Lam3,4 coupling reactions, in addition
to prove valuable starting materials in metal-free
transformations.5 Whereas arylboronates can be prepared by
the addition of electrophilic boron sources on arenes,6–13
catalysis provides for unique selectivity and greener
methodologies. The most common and active catalysts for the
Fig. 1 - Reported air-stable pre-catalysts for the metal-free C-H borylation of
heteroarenes (A-D) and the polymeric analogues presented in this work (P-R).
In order to facilitate the purification process of this metal-free
borylation reaction, we have been interested in the preparation
of heterogeneous ambiphilic materials.56,57 Incorporation of
FLPs on solid supports has been the focus of several research
groups in the past few years, mostly by grafting the active
a.Département de Chimie, Centre de de Catalyse et Chimie Verte (C3V), Université
Laval, 1045 Avenue de la Médecine, Québec (Québec), Canada, G1V 0A6
b Canada Research Chair in Green Catalysis and Metal-Free Processes
†Electronic Supplementary Information (ESI) available. CCDC 1892765-1892766. For
ESI and crystallographic data See DOI: 10.1039/x0xx00000x
moieties
on
silica,
carbon-based
materials
and
phosphorenes.58–63 However, since the borylation catalysts we
developed are based on the arylaminoborane architecture, it
was only logical to assume that polystyrene derivatives bearing
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
Dalton Transactions
Page 2 of 12
ARTICLE
Journal Name
ambiphilic functional groups could be prepared for catalytic The synthesis of the fluoride-protected aminoborane
View Article Online
DOI: 10.1039/C9DT00484J
applications. Some polystyrene-based polymers containing
boron functional groups are known.64–67 Boronic acids and
Scheme 1 Synthetic pathway for monomers 3-R from corresponding 4-N,N-
dialkylamino benzaldehydes.
trifluoroborate moieties have been incorporated on polymeric
backbones for applications such as saccharide binding68,69 and
optoelectronics.70,71 Interestingly, polymeric versions of BF3
containing styrene motifs were prepared by Barbaro et al. for
ion sensing applications (Fig 2, I
).72 On the other hand, styrenic
polymers containing N,N-dialkyl amino groups have been
known for several decades, notably as ion scavenging
purification resins.73,74 However, few styrenic compounds that
have both the desired dialkylamino and boron-containing
moieties are found in the literature. One interesting example of
an ambiphilic N/B containing resin is the polymeric version of
methylene bridged Wulff-type alkylamino boronic acid, which
has been used as saccharide sensors by Van Hest et al. (Fig 2, II).
i: NBS, NH4OAc (10 %) ii: (step 1) P(Ph)3CH3Br, n-BuLi (step 2) 1-R. iii: (step 1) n-BuLi
a
(step 2) B(OMe)3 (3 equiv) (step 3) KHF2, THF or MeOH, H3O+. Purified by vacuum
distillation.
75
However, these methylene bridged amines are expected to
precursors is illustrated in Scheme 1
. The first step involves the
be inactive towards C-H activation, because of the formation of
intramolecular N-B adducts, which does not readily generate
the active FLP required for catalysis. N-B isosteric analogues of
polystyrenes were also reported at the same period by the
groups of Jäkle, Klausen and Staubitz for their tuneable physical
properties (Fig 2, III).76–78 Although many FLPs have been
reported to act as polymerization catalysts,79,80 to the best of
our knowledge, the only work on polymeric versions of FLPs
report hierarchical network polymers for H2,CO2 and/or alkene
activation.81–84 These polymers often act as supported versions
of the classic triphenylphosphine/trispentafluorophenylborane
FLPs.
bromination of the 4-(N,N-dialkylamino)benzaldehyde
derivatives to generate the 2-brominated analogues (1-Et, 1-Me
and 1-Pip), as previously reported by Reddy et al.85 The
1
conversion can be monitored by H NMR spectroscopy where
the resonances of the hydrogen at the 3-position and of the
aldehyde are observed downfield around 8.03 (3JHH = 2 Hz) and
9.81 ppm, respectively. The other resonances for the aromatic
backbone were observed at around δ = 7.7 and 7.1 for H5 and
H6, respectively, in accordance with literature data.85 The
compounds were isolated in good to moderate yield using flash
chromatography. The lower conversion for
to the formation of the undesired 3-brominated analogue,
whereas lower overall conversion was observed for Et. The
1-Pip was attributed
1
-
yield for 1-Me was similar to the one reported for the smaller
scale synthesis.85
In order to obtain the vinylic precursors, a subsequent Wittig
reaction was performed to afford the styrene derivatives 2-Et
,
2-Me and 2-Pip in satisfying yield. As expected, the aldehyde 1H
NMR resonance at 9.81 ppm was replaced by the distinctive
vinyl resonance pattern, having two doublets at 5.19 (3JH-Htrans
=
11 Hz) and 5.65 ppm (3JH-Hcis = 18 Hz), and one multiplet centred
near 6.60 ppm. The apparition of the distinctive alkene moieties
(δ ≈ 119 and 113) at the expense of the aldehyde resonance (δ
≈ 190) was also observed by 13C NMR spectroscopy. Species 2-
Me and 2-Et can be obtained as clear oils by vacuum micro
distillation to ensure the elimination of the triphenylphosphine
oxide by-product. Because of the lower volatility and stability of
compound 2-Pip towards heat and light, it was purified as a
clear yellow oil by flash chromatography after precipitation of
the excess triphenylphosphine oxide in cold diethyl ether. All
compounds were analysed using ESI-MS and the values are in
agreement with the expected values in positive ionization. It
Fig. 2 - Structures of amino or trifluoroborate containing polystyrenes.
To generate heterogeneous C-H borylation catalysts and
contribute to the field of supported FLP catalysts, we report
herein the synthesis and polymerization of vinylic precursors
+
-
based on the structure of 1-HNR2 -2-BF3 -C6H4 (NR2 = NMe2
Me), NEt2 (Et) and piperidine (Pip)) borylation pre-catalysts.
(
These polymers were characterized thoroughly and their
activity towards the borylation of heteroarenes is reported.
should be noted that these species were stored at -35
℃
although species 2-Me and 2-Et exhibit good stability toward
temperature and light. Since 2-Pip exhibited rapid degradation
in the absence of solvent, it was kept in solution in a dark
environment. For these reasons, it is recommended to use
compound 2-Pip directly after synthesis.
Results and discussion
Precursor synthesis
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
The desired monomers 3-Me, 3-Et and 3-Pip were prepared methods as it can interact with radicals, or even serve as an
View Article Online
following a classic metal-halogen exchange procedure, followed initiator for radical polymerization.94 However, polymerization
DOI: 10.1039/C9DT00484J
by the addition of trimethyl borate as a boron electrophile. The can occur using 3.3 mol% of radical initiator
boron-functionalized N-alkyl styrene can then be treated with azabisisobutyronitrile (AIBN) in cyclohexanol. Hot cyclohexanol
excess potassium hydrogen fluoride in an acidified THF water was shown to dissolve monomers 3-R, but the resulting
solution to generate the trifluoroborate protected zwitterionic polymers were insoluble in these conditions.
monomers.37,55,86,87 The 3-NR2 zwitterions can be obtained as Cyclohexanol has been previously reported to increase the
white crystalline powders by precipitation from diethyl ether. porosity in macromolecular porous and swellable networks, a
As expected, the 11B NMR spectra of these compounds showed feature of interest in catalytic materials.95,96
a quadruplet (1JB-F = 50 Hz) in the typical region for quaternary
boron atoms (between 1 and 8 ppm), while the 19F NMR shows Polymers P-Me
, P-Et and P-Pip were obtained on a gram scale
a broad multiplet in the -130 to -140 ppm region. Suitable and precipitated from a mixture of diethyl ether and hexanes,
crystals for X-ray diffraction (XRD) studies were obtained by then washed with hot methanol or THF using a Soxhlet
slow evaporation of a saturated solution of the compound in apparatus. Respectable yields of 73, 72 and 83 % were obtained
acetone. Crystal structures of compounds 3-Me and 3-Et are for P-Me
,
P-Et and P-Pip, respectively. As described in the ESI†,
1
presented in Figure 3. Due to the instability of compound 3-Pip
,
it is possible to observe by H NMR spectroscopy the broad
it could not be characterized by XRD. However, NMR and ESI- resonances attributed to the moieties of the starting materials,
MS characterization are in accordance with the expected but without the typical vinylic resonances present in the styrene
product.
precursors. Presence of remaining cyclohexanol was observed
by H in P-Pip, even after multiple Soxhlet runs. It should be
1
Polymerization of the ansa-N,N-alkylammoniotrifluoborates noted that whereas cyclohexanol was observed for P-Et, it was
styrene precursors (3-R)
removed from the polymer under Soxhlet conditions. As in the
monomeric units, the 11B NMR spectra exhibit multiplets for the
BF3 moiety between 0 and 2 ppm, while 19F NMR spectra exhibit
a broad trifluoroborate resonance centred around -130 ppm.
As seen in Table 1, P-Me is exhibiting the lowest molecular mass
of all polymers, with Mn and Mw values of 16.5 and 26.6 kDa,
respectively. Both P-Et and P-Pip have similar molecular weights
with respective Mn and Mw of 29.0 and 72.3, and of 24.7 and
77.2 kDa, respectively. The polydispersity index ( )of 1.6 for P-
Đ
Me is relatively low, which is atypical for radical polymerization,
but the values for P-Et and P-pip of 2.5 and 3.1 are in the
expected range for radical polymerization techniques.97
Table 1 Results for polymerization of protected ansa-amino-fluoroborates styrenes 3-R
into polymers P-R.
Fig. 3 ORTEP structures of 3-Me (left, R1= 4.46 %) and 3-Et (right, R1= 5.39 %) with
anisotropic displacement ellipsoids at 50 % probability level. Aliphatic H atoms
were omitted for clarity.
Selected bond lengths (Å) and angles (o) for 3-Me: C(7)-
C(8) 1.31(2), B(1)-C(5) 1.615(2), N(1)-C(4) 1.486(2), B(1)-F(1) 1.361(3), F(1)-B(1)-
C(5) 112.0(2), C(4)-N(1)-C(9) 112.27(9), C(1)-C(7)-C(8) 127.7(1; 3-Et: C(7)-C(8)
1.314(4), B(1)-C(3) 1.621(4), N(1)-C(2) 1.485(3), B(1)-F(1) 1.398(4); F(1)-B(1)-C(3)
112.0(2), C(2)-N(1)-C(9) 112.4(2), C(5)-C(7)-C(8) 126.2(3).
Polymer
P-Me
Mw
Mn
Isolated
Yield
(%)a
Tg
Tc
Tm
Đ
(g/mol) (g/mol)
(oC)
According to literature precedents, alkylaminostyrenes and
boronic acid styrenes can undergo radical polymerization in
bulk or in solution.88,89 However, direct controlled radical
26600
16500
1.6
73%
142
155,143
203
P-Et
72300
77200
29000
24700
2.5
3.1
72 %
83 %
183 NA(≥275) NA(≥275)
195 NA(≥250) NA(≥250)
polymerization of monomers 3-Et, 3-Me and 3-Pip did not
P-Pip
aRelative to the amount of monomer at the start of the reaction
afford the expected polymers using literature inspired methods
such as reversible addition-fragmentation polymerization
(RAFT),75,90 nitroxide mediated polymerization (NMP)91 and
atom transfer polymerization (ATRP).64,92,93 It is suspected that
the fluoroborate moieties reduce the efficiency of these
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
Dalton Transactions
Page 4 of 12
ARTICLE
Journal Name
8), but increased slightly the activity of P-Pip, obtaining 60 %
View Article Online
conversion (entry 14). It should be notedDtOhIa: 1t0t.h10e39te/Cm9DpTe0ra04tu84reJ
Characterization results of the polymers are summarized in
Table 1. According to TGA analysis, P-Et and P-Me lose
significant mass (20 %) around 250 oC, which is attributed to the
loss of BF3 and NR2 groups. Although P-Pip shows a similar
degradation event at 250 oC, an additional mass loss of
o
of 90 C is optimal since running the reaction under neat
o
conditions at 80 or 110 C (entries 4-6) with P-Et led to
conversions under 50 %. Finally, to confirm that the polymer is
really doing catalysis rather than monomers 3-R, the molecular
species were tested under neat conditions. As can be seen in
o
approximatively 10% was observed between 150 and 200 C,
which was attributed to the loss of cyclohexanol that is
incorporated in the polymeric structure. The DSC analysis was
conducted within the temperature range required to avoid
decomposition. The glass transition temperature (Tg) of the
Table 2 Condition optimization for the catalytic borylation of 1-methylpyrolle.
polymers P-Me
,
P-Et and P-Pip were observed at 142, 183, and
o
195 C, respectively. It is important to note that these Tg
measurements can be altered by the presence of residual
solvents (in the case of P-Pip particularly), that can act as a
plasticizer. Whereas the melting temperature (Tm) of P-Et and
P-Pip was outside the temperature range of the measurements,
it was possible to determine that P-Me has a melting
%
Temperature
(oC)
Entry
Compound
Solvent Time
Conversion
(1H NMR)
o
1
2
3
4
5
6
7
8
9
P-Me
P-Me
P-Et
P-Et
P-Et
P-Et
P-Et
P-Et
P-Et
P-Pip
Neat
CDCl3
Neat
Neat
Neat
Neat
CDCl3
CDCl3
CDCl3
Neat
16h
36h
3h
16h
16h
16h
16h
16h
36h
3h
90
110
90
90
80
110
90
110
110
90
18 %
0 %
temperature of 203 C. Polymer P-Me also exhibit additional
crystallization events (Tc) at 143 and 155 oC.
25 %
87 %
44%
39 %
0 %
47 %
49%
23 %
Catalysis Results
-
Since species NR2H+-C6H4-BF3 (NR2 = NMe2, NEt2 and piperidine)
have been shown to act as efficient pre-catalysts for the
borylation of heteroarenes, we investigated polymers P-Me, P-
Et and P-Pip for similar reactivity. The results are presented in
Table 2 using 1-methylpyrolle as the benchmark substrate. In a
typical reaction, 5 mol % of one of the pre-catalytic polymers P-
10
11
12
13
P-Pip
P-Pip
P-Pip
Neat
CDCl3
CDCl3
16h
16h
16h
90
90
98 %
Traces
28%
R
was added in a J-young NMR tube and allowed to react in the
given conditions. It is important to highlight that the polymers,
both before and during catalysis, remain insoluble in solvent or
in neat conditions. Indeed, no resonance associated with the
polymer was observed by NMR spectroscopy with or without
HBpin. For the reactions under neat conditions, the NMR
solvent was added after the catalytic transformation took place
to assess the borylation of the substrate. The conversion was
measured according to the shift of the CH3 moiety as monitored
by 1H NMR, going from a singlet at 3.69 ppm for 1-methylpyrolle
to a singlet at 3.87 ppm for the 3-borylated analogue. As
recently reported with the homogeneous analogues,37,38 the
reaction runs better under neat conditions than in solution. As
110
14
15
16
17
P-Pip
3-Me
3-Et
CDCl3
Neat
Neat
Neat
36h
12h
12h
12h
110
90
90
60 %
Traces
12 %
3-Pip
90
Traces
entries 15 to 17, they all exhibit very poor catalytic properties,
which is expected since alkenes are known to quench catalysis
by undergoing hydroboration with the –BH2 moiety of catalysts
NR2-C6H4-BH2 and HBpin.46
*When in CDCl3, 400 uL are added to the J-Young NMR tube. Catalyst loading was
calculated based on the monomeric unit. Equivalents of pinacolborane are
calculated according to 1-methylpyrolle. 0.3 equivalents of HBpin are required to
activate pre-catalysts P-R.
a comparative standpoint, pre-catalysts
B and C from Figure 1
can achieve complete borylation (96-97 %) of 1-methylpyrrole
in 2 h under neat conditions at 80 oC. As for the NMe2 analogue,
only 23 % borylation was achieved in the same time.37 The least
active of the polymers, P-Me, has a conversion of 18 % under
neat conditions for 16 h at 90 oC (entry 1), whereas no reaction
Optimal conditions (no solvent for 16 h at 90 oC) were used for
the substrate scope presented in Figure 4. In all cases, either P-
Et or P-pip gave the highest conversions, but they remain low in
comparison to the previously reported homogeneous pre-
catalysts [NR2-C6H4-BH2]2 (NR2 = NEt2 or Piperidinyl), which gave
in every case high conversions.38 Whereas the cleavage of the
dimeric species [NR2-C6H4-BH2]2 to generate the active FLP NR2-
C6H4-BH2 was found to be rate determining in the homogeneous
systems,37 we expect that the required degree of freedom to
generate these specific and inactive dimers having an ordered
o
was observed in a CDCl3 solution after 36 h at 110 C (entry 2).
Polymers P-Et and P-Pip are both showing good conversions
under neat conditions (16 h at 90 oC) of 87 and 98%,
respectively, which follows the trend observed for the
homogeneous analogues (entries 4 and 11). Similarly to P-Me
,
no conversion was observed after 16 h in a CDCl3 solution at 90
oC with P-Et and P-Pip (entries 7 and 12), but conversions below
o
50 % were observed at 110 C (entries 8 and 13). Running the
reaction longer (36 h) had no effect on the P-Et catalyst (entry
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
6-membered ring might be limited in a more rigid polymer. out for each polymer. As seen in Figure 5, all three VmieawtAertriicalelsOnclainne
Therefore, more active sites should be present and higher be recycled and remain catalytically activDeO. PI:o10ly.1m03e9r/sC9PD-MT0e04a8n4dJ
activity should be observed. Since it is not the case, we suppose P-Et are durable and their conversions remained almost
that several of the FLP sites on the polymer are not accessible unaltered after three filtration/reaction steps. The durability of
for the substrates because of limited contact surface and these polymers is not surprising when correlating with the TGA
diffusion, problems that are observed with polymeric resins, and DSC results. On the other hand, P-Pip does not show the
giving lower catalysis efficiencies.98 It was recently proposed same durability, and even if it is more active than the other two
that FLP polymeric materials can exhibit poor properties when in the first run, the conversion drops drastically to 31 % at the
more than 10 % of FLP incorporation is presented in polystyrene third run. Although the exact deactivation pathway could not be
based polymers, which seems to be the case of our system as found, it was attributed to the presence of cyclohexanol. To
well.82
confirm this hypothesis, polymer P-Et* was synthesized
similarly to P-Et, but was not further purified via Soxhlet
apparatus, thus keeping some residual cyclohexanol in the
polymeric network. As can be seen in Figure 5, a similar
behavior was observed for P-Et* than for P-Pip, with the
catalytic activity of the former catalyst material dropping to 11
% conversion after three runs. It was shown in recent studies
that excess alcohol can form B-O bonds when in presence of a
BH2 moiety, thus poisoning the desired active form of the
catalyst by favoring undesired metathesis pathways.99
98
100
87
85
83
90
80
70
60
50
40
30
20
10
0
75
55
31
30
18
15
15
11
1
2
3
Run number
Fig. 5- Recyclability tests for resins P-R for the borylation of 1-methylpyrrole using
optimized conditions. Conversions were determined by the relative integration of
CH3 peaks of 2-borylated 1-methylpyrolle (3.87 ppm) vs native 1-methylpyrolle
(3.69 ppm). •= P-Me •= P-Et •= P-Pip •= P-Et*.
Fig. 4 - Substrate scope for the borylation reactions catalyzed by P-R.
a 1100C, 48h,
400 μL CDCl3.
As one of the advantages of a solid support is its recyclability,
durability studies were performed on the synthesized materials.
In a typical study, 5 mol% of pre-catalyst P-R was allowed to
react in a J-Young NMR tube along with 23 equiv of HBpin and
In order to further investigate the properties of the polymer
under catalytic conditions, we analysed by NMR spectroscopy
P-Et after it reacted with 23 equiv of HBpin at 110 C for 48 h.
o
Investigation by 11B NMR of P-Et showed the expected
formation of the -BH2 moiety, which is catalytically active, by the
presence of a broad peak at 35 ppm. In addition, peaks
attributed to FBpin (21.2 ppm), residual BF3 (q, 0.50 ppm) and
o
20 equiv of 1-methylpyrrole. After 16 hours at 90 C, the
conversion was assessed by 1H NMR spectroscopy. The
remaining insoluble activated polymer was filtered in the
glovebox, washed three times with CDCl3 and dried in vacuo
using Schlenk techniques, and replaced under the same
catalytic conditions. Overall, three catalytic runs were carried
-
BFx (-0.8 to -1 ppm) were also identified, suggesting that not all
of the fluoroborate moieties are catalytically active. Resonances
for the corresponding fluorinated compounds were also
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 6 of 12
ARTICLE
Journal Name
-
observed in the 19F NMR spectra (BF3 at 150.1 ppm and FBpin mmol/L) and calibrated with Agilent technologies High Easy
View Article Online
at -153.0 ppm).
vialsTM polystyrene standards using a DrOeIf:r1a0c.1t0iv3e9/Ci9nDdTe0x04(8R4IJ)
detector. The experiments were performed using a KF-804
column. The system was purged overnight with DMF/LiBr 20
mM as the mobile phase. The RI detector was left on to stabilize
at sensibility level 10. Baseline of the polymer peaks were
normalized and analyzed with the calibration curve made with
Agilent PS standards (logM in function of elution time) (see ESI).
Mw and Mn were calculated using statistical treatments of raw
data with Microsoft Office Excel. The flow was set to 1mL/min
at c.a. 1000 psi of pressure. All samples are soluble in DMF and
were filtered on a 0.45 μM PTFE filter prior to injection.
Conclusions
The synthesis of active and recyclable heterogenous polymeric
species capable of C-H borylation could help the manufacturing
of large scale borylation technologies. Whereas the kilogram
scale-up of the FLP borylation was recently reported, using
recyclable catalysts could lead to greener processes. To the
best of our knowledge, species P-Me, P-Et and P-Pip, which can
be made in good yields, represent the first examples of
polymeric/oligomeric metal-free ambiphilic polymers for the C-
H borylation of heteroarenes. Although the activity of these
polymers is lower than the homogeneous analogues, polymer
P-Et proved durable conserving the same catalytic activity after
three runs. The next step in our development will be to optimize
the materials properties in order to increase the amount of
accessible functional groups and to obtain similar activity than
with the homogeneous systems. Also of interest is the use of
these polymers for the borylation reaction under flow
conditions and application to the metal-free system of
borylative dearomatization of indoles.100 Polymer P-Et
represents a great candidate for further optimization, but a new
synthetic method needs to be developed in the case of P-Pip to
remove residual cyclohexanol.
TGA analysis was performed with Mettler® TGA/SDTA851 at 20
o
oC / min up to 600 C and the data was treated with STARe
software. DSC analysis were performed with Mettler® DSC823
and also treated directly with integrated STARe software suite.
DSC standard curve was performed with pre-weighted indium
sample and the polymer samples were analyzed in aluminum
capsules. A first ramp of the DSC analysis was performed from
25 to 250 oC at 20 oC/min followed by a 1 min isotherm to erase
thermal history of the samples. Measurements were extracted
from the two-following cooling/heating ramps ranging from 25
to 250 oC at 20oC/min.
Crystallographic details
Crystals were mounted on CryoLoops with Paratone-N and
optically aligned on
a
Bruker SMART APEX-II X-ray
diffractometer with 1K CCD detector using a digital camera.
Initial intensity measurements were performed using a fine-
focused sealed tube, graphite-monochromatic, X-ray source
(Mo Kα, λ = 0.71073 Å) at 50 kV and 30 mA. Standard APEX-II
software package was used for determining the unit cells,
generating the data collection strategy, and controlling data
collection. SAINT102 was used for data integration including
Lorentz and polarization corrections. Semi-empirical absorption
corrections were applied using SCALE (SADABS103). The
structure was solved by direct methods and the refinement was
carried out using SHELX2014/7.104 All the calculations have been
performed with the OLEX2 software.105 All of the H atoms on C
atoms were generated geometrically and refined in riding
model (AFIX commands). In case of compound 3-Me, disorder
of the BF3 moiety was treated using two parts, SIMU, RIGU and
DELU commands. For compound 3-Et, disorder of the BF3 unit
was only treated with SIMU commands. Atomic coordinates and
additional structural information are provided in the .cif files of
the ESI†. Crystallographic data have been deposited with CCDC
(CCDC 1429581-1429583).
Experimental section
General experimental
All operations using air and moisture sensitive compounds were
performed under conventional Schlenk techniques (N2
atmosphere) or in a glovebox. THF, diethyl ether, toluene and
hexanes were purified by distillation over Na/benzophenone.
CDCl3 was dried by distillation over P2O5. Workup and column
chromatography were performed using technical grade
solvents and reagents. 1-Methylpyrrole was distilled from KOH.
Pinacolborane was purchased from Millipore Sigma and used as
received. 6-Cl- and 6-F-Me-indoles were synthesized using
literature procedures.47,101 Other substrates were used as
received from Millipore Sigma or Oakwood chemicals without
further purification.
NMR spectra were recorded on an Agilent Technologies NMR
spectrometer at 500.130 MHz (1H), 125.758 MHz (13C), 160.46
MHz (11B), and 470.592 MHz (19F), and on a Varian Inova NMR
AS400 spectrometer at 400.130 MHz (1H), 376.498 MHz (19F),
and 100.580 MHz (13C). 1H NMR and 13C{1H} NMR chemical shifts
are referenced to residual protons or carbons in deuterated
solvent. 11B{1H} was calibrated using as external reference
BF3.Et2O. Multiplicities are reported as singlet (s), broad singlet
(bs), doublet (d), triplet (t), quadruplet (q) and multiplet (m).
Chemical shifts δ are reported in ppm. Coupling constants are
reported in Hz.
Synthetic procedures
2-bromo-N,N-dimethyl-4-vinylaniline (2-Me).
In a flame-dried Schlenk flask, 4.01 mL of a 2.5 M solution of n-
butyllithium in hexanes (1.05 equiv, 10 mmol) was syringed to a
stirring solution of 3.58 g (1.05 equiv, 10 mmol) of
methyltriphenylphosphonium bromide in 250 mL of dry THF at
Mass spectrometry analysis was carried out on an Agilent
Technologies 6210 LC Time of Flight Mass Spectrometer. SEC-
GPC chromatograms were recorded in DMF/LiBr mixture (20
o
-40 C. After the addition, the bath was removed and the
solution was left to stir at room temperature for 1 h, before
6 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
being placed in a -40 oC bath. 1 equiv (9.54 mmol, 2.18 g) of the stirring solution 3.58
ARTICLE
g
(1.05 equiv, 10 ViewmAmrticolel)Onlionef
DOI: 10.1039/C9DT00484J
3-bromo-4(dimethylamino)benzaldehyde 1-Me was slowly methyltriphenylphosphonium bromide in 250 mL of dry THF at
o
added via syringe to the red-orange solution. The cold bath was -40 C. After the addition, the bath was removed, and the
removed, and the reaction mixture was allowed to stir solution was left to stir at room temperature for 1 h before
o
overnight under a nitrogen atmosphere. After 16 h, the cloudy being placed in a -40 C bath. 1.0 equiv (9.54 mmol, 2.56 g) of
mixture was concentrated in vacuo and extracted 3 times with the 3-bromo-4(piperidin-1-yl)benzaldehyde 1-Pip was slowly
100 mL of diethyl ether and water. The organic extracts were added via syringe to the red-orange solution. The cold bath was
washed with a saturated solution of Na2CO3, with brine, and removed, and the reaction mixture was allowed to stir
then dried on MgSO4. The mixture was filtered on a short silica overnight under a nitrogen atmosphere. After 16 h, the cloudy
pad, eluted with diethyl ether and dried in vacuo. This process mixture was concentrated in vacuo and extracted 3 times with
was repeated until no trace of triphenylphosphine oxide could 100 mL portions of diethyl ether and water. The organic extracts
be found by 31P and 1H NMR spectroscopy. The desired product were washed with a saturated solution of Na2CO3, with brine,
was obtained as a pale-yellow oil and was further purified by and then dried on MgSO4. The mixture was filtered on a short
microdistillation under reduced pressure (70 oC, c.a. 1mm of Hg) silica pad, eluted with diethyl ether and dried in vacuo. This
to afford 2-Me as a clear oil (1.29 g, 60 % yield). 1H NMR (CDCl3, process was repeated until no traces of triphenylphosphine
400 MHz): δ 7.62 (d, 1H, JH-H=2 Hz, H3); 7.29 (dd, 1H, JH-H= 2 Hz, oxide could be found by 31P and 1H NMR spectroscopy. Product
8 Hz, H5); 7.03 (d, 1H, JH-H=8 Hz, H6); 6.70-6.41 (m, 1H, H7); 5.65 2-Pip was obtained as a pale yellow to deep red oil and used
(d, JH-H= 18 Hz, 1H, H9); 5.19(d, 1H, JH-H= 11 Hz, H9); 2.81 (s, 6H, directly for further synthesis (2.23 g, 88% yield). 1H NMR (CDCl3,
H8). 13C{1H} NMR (CDCl3, 126 MHz): δ 151.4 (s, 1C, C1), 135.0, 400 MHz): δ 7.63 (d, 1H, JH-H=2 Hz, H3); 7.29 (dd, 1H, JH-H= 2 Hz,
133.6, 131.5, 125.9, 120.1 (s, 5C, C2, C3, C4, C5 and C6); 119.0 8 Hz, H5); 7.05- 6.95 (m, 1H, H6); 6.60 (dd, 18 Hz, 11 Hz, 1H,
(s, C, C7), 113.4 (s, 1C, C9), 44.3 (s, 2C, C8). ESI-MS (positive H7); 5.65 (d, JH-H= 18 Hz, 1H, H9); 5.20 (d, 1H, JH-H= 11 Hz, H9);
ionization): [M-H]+ : 228.0160 (theoretical : 228.0211).
3.06-2.81 (m, 4H, H8); 1.82-1.67 (m, 4H, H10); 1.63-1.53 (m, 2H,
H11). 13C{1H} NMR (CDCl3, 126 MHz): δ 151.4 (s, 1C, C1), 135.2,
133.4, 131.3, 126.0, 120.6 (s, 5C, C2, C3, C4 C5 and C6); 120.0 (s,
C, C7), 113.3 (s, 1C, C9), 53.3 (s, 2C, C8), 26.2 (s, 2C, C10), 24.1
(s, 1C, C11). ESI-MS (positive ionization) [M-H]+: 268.0504
(theoretical: 256.0523).
2-bromo-N,N-diethyl-4-vinylaniline (2-Et)
In a flame-dried Schlenk flask, 4.01 mL of a 2.5 M solution of n-
butyllithium in hexanes (1.05 equiv, 10 mmol) was syringed to a
stirring solution of 3.58 g (1.05 equiv, 10 mmol) of
methyltriphenylphosphonium bromide in 250 mL dry THF at -40
oC . After the addition, the bath was removed and the solution
was left to stir at room temperature for 1 h, before being placed
in a -40 oC bath. 1 equiv (9.54 mmol, 2.44 g) of the 3-bromo-4-
(diethylamino)benzaldehyde 1-Et was slowly added via syringe
to the red-orange solution. The cold bath was removed, and the
reaction mixture was allowed to stir overnight under nitrogen
atmosphere. After 16h, the cloudy mixture was concentrated in
vacuo and extracted 3 times with 100 mL of diethyl ether and
water. The organic extracts were washed with a saturated
solution of Na2CO3, with brine, and dried on MgSO4. The mixture
was filtered on a short silica pad, eluted with diethyl ether and
dried in vacuo. This process was repeated until no traces of
(2-(dimethylammonio)-5-vinylphenyl)trifluoroborate (3-Me)
In a flame dried Schlenk flask, 20 mL of dry hexanes was
syringed to 757 mg (3.35 mmol) of 2-Me at -78 oC. 1.34 mL of a
2.5 M solution of n-butyllithium in hexanes (1.01 equiv, 3.38
mmol) was slowly added via syringe to the stirring solution. The
solution was stirred at -78 oC for 1 hour until the apparition of a
white precipitate. The white precipitate was dissolved in 20 mL
o
of dry toluene at -78 C and 3 equiv of trimethyl borate (1.12
mL, 1.04 g, 10.1 mmol) were added in one fraction via syringe.
The cold bath was removed, and the reaction mixture was
allowed to stir under a nitrogen atmosphere for 12 h. The
solution was filtered on a sintered glass disk and concentrated
in vacuo. After dissolution of the crude oil in 10 mL of THF,
excess KHF2 (1.0 g, 12.8 mmol, 3.8 equiv) and 1 mL of a 1M HCl
solution were added in a round bottomed flask. After 4 h of
stirring at ambient temperature, the solution was evaporated
to dryness, dissolved in 3 portions of 10 ml of hot acetone,
concentrated on the rotary evaporator and precipitated in 250
mL of diethyl ether. The white solid was filtered and then
thoroughly washed with hexanes and diethyl ether and then
dried in vacuo to afford 3-Me as a white crystalline solid (432
mg, 60 % yield). Crystals suitable for XRD were obtained by slow
evaporation in acetone. 1H NMR (acetone-d6, 500 MHz): δ 7.64-
7.66 (bs, 1H, H3); 7.62 (d, 1H, JH-H= 8 Hz, H5); 7.47 (d, 1H, JH-H= 8
Hz, H6); 6.77 (dd, JH-H= 17 Hz, 11 Hz, 1H, H7); 5.82 ( d, JH-H= 18
Hz, 1H, H9); 5.27 (d, 1H, JH-H= 11 Hz, H9); 3.89-3.71 (bs, 1H, N-
H); 3.42 (s, 6H, H8). 13C {1H} NMR (acetone-d6, 126 MHz): δ
triphenylphosphine oxide could be found by 31P and H NMR
1
spectroscopy. The desired product was obtained as a pale-
yellow oil and was further purified by microdistillation under
reduced pressure (80 oC, c.a. 1mm of Hg) to afford 2-Et as a clear
1
oil (1.33g, 55% yield). H NMR (CDCl3, 400 MHz): δ 7.64 (d, 1H,
JH-H=2 Hz, H3); 7.28 (dd, 1H, JH-H= 2 Hz, 8 Hz, H5); 7.03 (d, 1H, JH-
H=8 Hz, H6); 6.60 (dd, 18 Hz, 11 Hz, 1H, H7); 5.66 (d, JH-H= 18 Hz,
1H, H9); 5.20 (d, 1H, JH-H= 11 Hz, H9); 3.10 (q, 4H, JH-H= 7 Hz, H8);
1.03 (t, 6H, JH-H= 7 Hz, H10). 13C{1H} NMR (CDCl3, 126 MHz): δ
148.5 (s, 1C, C1), 135.2, 134.0, 131.3, 125.4, 123.7, (s, 5C, C2,
C3, C4 C5 and C6); 122.4 (s, C, C7), 113.6 (s, 1C, C9), 47.0 (s, 2C,
C8), 12.2 (s 2C, C10). ESI-MS (positive ionization) [M-H]+:
256.0500 (theoretical: 256.0520).
1-(2-bromo-4-vinylphenyl) piperidine (2-Pip)
In a flame-dried Schlenk flask, 4.01 mL of a 2.5 M solution of n- 148.2 (s, 1C, C1), 136.8, 135.9, 131.8, 125.4, (s, 4C, C3, C4 C5
butyllithium in hexanes (1.05 equiv, 10 mmol) was syringed to a and C6); 117.5 (s, C, C7), 113.0 (s, 1C, C9), 46.3 (s, 2C, C8).11B{1H}
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 7
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 8 of 12
ARTICLE
Journal Name
NMR (acetone-d6, 160 MHz): δ 7.9 (q, JB-F = 50 Hz, 1B).19F NMR afford compound 3-Pip as a pink-white solid (242 mg, 30 %
View Article Online
(acetone -d6, 470 MHz): δ -133.2 (m, 3F). ESI-MS (positive yield). 1H NMR (acetone-d6, 500 MHz): δ D7O.6I8: 10(d.1,0J3H9-/HC=92DTH0z0,418H4J,
ionization): [M-BF2 (-F atom)]+: 196.1224 (theoretical: H3); 7.15 (d, 1H, JH-H= 8 Hz, H5); 6.92-6.82 (m, 1H, H6); 6.65 (dd,
196.1109).
(JH-H= 17 Hz, 11Hz), 1H, H7); 5.57 (d, JH-H= 18 Hz, 1H, H9); 4.98
(d, 1H, JH-H= 11Hz, H9); 3.19-3.05 (m, 4H, H8); 1.78-1.69 (m, 4H,
H10); 1.59-1.51 (t, 2H, H11). 13C{1H} NMR (acetone-d6, 126
MHz): δ 138.0, 132.8, 124.4, 116.7,120.7, (s, 4C, C2, C3, C5 and
C6); 116.8 (s, C, C7), 109.5 (s, 1C, C9), 54.6 (s, 2C, C8), 25.8 (s 2C,
C10), 23.8 (s, 1C, C11). 11B{1H} NMR (acetone-d6, 160 MHz): δ
3.4 (q, JB-F = 50 Hz, 1B).19F NMR (acetone-d6, 470 MHz): δ -138.5
(m, 3F). ESI-MS (positive ionization) [M-BF2 (-F atom)]+:
236.1566 (theoretical: 236.1422).
(2-(diethylammonio)-5-vinylphenyl)trifluoroborate (3-Et)
In a flame dried Schlenk flask, 20 mL of dry hexanes was
syringed to 851 mg (1 equiv, 3.35 mmol) of 2-Et at -78 oC. 1.34
mL of a 2.5M solution of n-butyllithium in hexanes (1.01 equiv,
3.38 mmol) was slowly added via syringe to the stirring solution.
The solution was stirred at -78 oC for 1 hour until the apparition
of a white precipitate. The white precipitate was dissolved in 20
mL of dry toluene at -78 oC and 3 equiv of trimethyl borate (1.12
mL, 1.04 g, 10.1 mmol) were added in one fraction via syringe.
The cold bath was removed, and the reaction was allowed to
stir overnight under a nitrogen atmosphere. The solution was
filtered on sintered glass disk and concentrated in vacuo. After
dissolution of the crude oil in 10 mL of THF, excess KHF2 (1.0 g,
12.8 mmol, 3.8 equiv) and 1mL of a 1 M HCl solution were added
in a round bottomed flask. After 4 h of stirring at ambient
temperature, the solution was evaporated to dryness, dissolved
in 3 portions of 10 ml of hot acetone, concentrated on the
rotary evaporator and precipitated in 250 mL of diethyl ether.
After filtration, the white solid was thoroughly washed with
hexanes and diethyl ether and then dried in vacuo to afford 3-
Et as an off-white solid (489 mg, 60 % yield). Crystals suitable
for XRD were obtained by slow evaporation in acetone. 1H NMR
(CDCl3, 500 MHz): δ 9.23 (bs, 1H, N-H); 7.84 (bs, 1H, H3); 7.44
(d, 1H, JH-H= 8 Hz, H5); 7.09 (d, 1H, JH-H= 8 Hz, H6); 6.74 (dd, JH-
H= 17 Hz, 11 Hz, 1H, H7); 5.82 (d, JH-H= 18 Hz, 1H, H9); 5.31 (d,
1H, JH-H= 11 Hz, H9); 3.79 (bs, 4H, H8); 3.44 (bs, 2H, H8); 1.23 (t,
6H, JH-H= 7 Hz, H10). 13C{1H} NMR (CDCl3, 126 MHz): δ 138.3,
138.1, 135.9, 132.7, 126.4 (s, 5C, C2, C3, C4 C5 and C6); 117.0 (s,
C, C7), 115.5 (s, 1C, C9), 54.5 (s, 2C, C8), 10.5 (s 2C, C10). 11B{1H}
NMR (CDCl3, 160 MHz): δ 3.02 (q, JB-F = 50 Hz, 1B).19F NMR
(CDCl3, 470 MHz): δ -136.7 (m, 3F). ESI-MS (positive ionization):
[M-BF2(-F atom)] +: 224.1534 (theoretical: 224.1422).
General procedure for the preparation of polymers P-R
In a flame dried Schlenk flask, 4.65 mmol of the corresponding
trifluoroborate monomer 3-R was agitated in 30 mL of
cyclohexanol at 60 oC until most of the monomer was
solubilized. The solution was cooled at room temperature and
3.3 mol% of recrystallized AIBN (25 mg) were added. The
reaction mixture was degassed by three freeze-pump-thaw
cycles and allowed to stir under nitrogen atmosphere for 48 h
at a constant temperature of 90oC. The reaction mixture was
added to 500 ml of a 80:20 solution of diethyl ether/hexanes
o
and left to precipitate at -35 C. The solids were filtered and
washed with hot THF using a Soxhlet apparatus. The polymers
were dried in vacuo and characterized by multi-elemental NMR
analysis in deuterated polar solvents (DMSO-d6 or D2O/HCl (1%)
mixture), depending on the solubility of the polymeric
compound. In the case of the NMR in acidified aqueous
conditions, the product partially degrades in its boronate
version, as expected†. Pristine polymers P-R were analyzed by
TGA and DSC. For SEC-GPC analysis, the polymer was solubilized
in the DMF/LiBr mixture and filtered prior to analysis†.
General procedure for the metal free borylation of heteroarenes
In a nitrogen-filled glovebox, HBpin and the heteroaromatic
substrate were added in a J-Young NMR tube. 0.023 mmol of
the pre-catalysts P-R (5 mg for P-Me, 5.6 mg for P-Et and 5.9 mg
for P-pip) were added to the J-young tube along with 400 μL of
CDCl3 or in neat conditions. The tube was sealed and put to heat
for 16h or 32h. The tube was re-entered in the glovebox and
Trifluoro(2-(piperidin-1-um-1-yl)-5-vinylphenyl) borate (3-Pip)
In a flame dried Schlenk flask, 20 mL of dry hexanes was
syringed to 892 mg (3.35 mmol) of 2-Pip at -78 oC
. 1.34 mL of a
2.5M solution of n-butyllithium in hexanes (1.01 equiv, 3.38
mmol) was slowly added via syringe to the stirring solution. The
solution was stirred at -78oC for 1 hour until the apparition of a
white precipitate. The white precipitate was dissolved in 20 mL
1
filled with dry CDCl3 to record the H NMR conversion. The
conversions were monitored based on the integration of new
peaks on the spectrum that are attributed to the reported
borylated substrates (See ESI†).
o
of dry toluene at -78 C and 3 equiv of trimethyl borate (1.12
mL, 1.04 g, 10.1 mmol) were added in one fraction via syringe.
The cold bath was removed, and the reaction was allowed to
stir overnight under nitrogen atmosphere. The solution was
filtered on sintered glass disk and concentrated in vacuo. After
dissolution of the crude oil in 10 mL of THF, excess KHF2 (1.0 g,
Conflicts of interest
There are no conflicts to declare.
12.8 mmol, 3.8 equiv) and 1mL of a 1 M HCl solution were added Acknowledgements
in a round bottomed flask. After 4h of stirring at ambient
This work was supported by the National Sciences and Engineering
temperature, the solution was evaporated to dryness, dissolved
in 3 portions of 10 ml of hot acetone, concentrated on the
rotary evaporator and precipitated in 250 mL of diethyl ether.
After filtration, the solid was washed with diethyl ether to
Research Council (NSERC) of Canada and the Centre de Catalyse et
Chimie Verte (Quebec). N.B. acknowledges NSERC for scholarships.
We acknowledge F. Otis for help with TGA, DSC and SEC-GPC analysis.
We acknowledge P. Audet for help with NMR and HRMS analysis. We
8 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 9 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
acknowledge Pr. J.-F. Morin for helpful insights. N.B. would like to
acknowledge G. Laurent and L. Harter for help in precursor synthesis
and purification. F.-G.F. also thanks NSERC for a Canada Research
Chair.
23
24
25
26
27
28
29
30
S. A. Westcott, H. P. Blom, T. B. Marder and RV.ieTw. BAratikcleerO, nJl.ine
Am. Chem. Soc., 1992, 114, 8863–8869.
G. A. Molander, S. L. J. Trice and S. D. Dreher, J. Am. Chem.
Soc., 2010, 132, 17701–17703.
K. L. Billingsley, T. E. Barder and S. L. Buchwald, Angew.
Chem., Int. Ed., 2007, 46, 5359–5363.
T. Ishiyama, M. Murata and N. Miyaura, J. Org. Chem.,
1995, 60, 7508–7510.
K. C. Lam, T. B. Marder and Z. Lin, Organometallics, 2010,
29, 1849–1857.
T. Hatanaka, Y. Ohki and K. Tatsumi, Chem. - Asian J., 2010,
5, 1657–1666.
T. J. Mazzacano and N. P. Mankad, J. Am. Chem. Soc., 2013,
135, 17258–17261.
T. Dombray, C. G. Werncke, S. Jiang, M. Grellier, L. Vendier,
S. Bontemps, J. B. Sortais, S. Sabo-Etienne and C. Darcel, J.
Am. Chem. Soc., 2015, 137, 4062–4065.
H. Zhang, S. Hagihara and K. Itami, Chem. Lett., 2015, 44,
779–781.
J. V Obligacion, S. P. Semproni and P. J. Chirik, J. Am. Chem.
Soc., 2014, 136, 4133–4136.
T. Furukawa, M. Tobisu and N. Chatani, Chem. Commun.,
2015, 51, 6508–6511.
M. Monai, M. Melchionna and P. Fornasiero, in Advances
in catalysis, ed. C. Song, Academic Press, 2018, vol. 63, pp.
1–73.
M.-A. Légaré, M.-A. Courtemanche, É. Rochette and F.-G.
Fontaine, Science, 2015, 349, 513–516.
F.-G. Fontaine, M.-A. Courtemanche, M.-A. Légaré and É.
Rochette, Coord. Chem. Rev., 2017, 334, 124–135.
J. Légaré Lavergne, A. Jayaraman, L. C. Misal Castro, É.
Rochette and F. G. Fontaine, J. Am. Chem. Soc., 2017, 139,
14714–14723.
A. Jayaraman, L. C. Misal Castro and F.-G. Fontaine, Org.
Process Res. Dev., 2018, 22, 1489–1499.
F.-G. Fontaine and É. Rochette, Acc. Chem. Res., 2018, 51,
454–464.
G. C. Welch, R. R. San Juan, J. D. Masuda and D. W.
Stephan, Science, 2006, 314, 1124–1126.
G. Erker and D. W. Stephan, Frustrated Lewis Pairs I and II,
Springer- Verlag Berlin Heidelberg, Berlin, 2013.
F.-G. Fontaine and D. W. Stephan, Philos. Trans. R. Soc. , A,
2017, 375, 20170004.
D. W. Stephan, Science, 2016, 354, 1248.
D. W. Stephan, J. Am. Chem. Soc., 2015, 137, 10018–10032.
É. Rochette, M. A. Courtemanche and F. G. Fontaine,
Chem. - Eur. J., 2017, 23, 3567–3571.
K. Chernichenko, M. Lindqvist, B. Kótai, M. Nieger, K.
Sorochkina, I. Pápai and T. Repo, J. Am. Chem. Soc., 2016,
138, 4860–4868.
Q. Yin, H. F. T. Klare and M. Oestreich, Angew. Chem., Int.
Ed., 2017, 56, 3712–3717.
DOI: 10.1039/C9DT00484J
Notes and references
1
2
3
D. G. Hall, Boronic Acids, Wiley-VCH Verlag GmbH & Co.
KGaA, Weinheim, Germany, 2011.
N. Miyaura and A. Suzuki, Chem. Rev., 1995, 95, 2457–
2483.
P. Y. S. Lam, C. G. Clark, S. Saubern, J. Adams, M. P.
Winters, D. M. T. Chan and A. Combs, Tetrahedron Lett.,
1998, 39, 2941–2944.
4
5
6
D. M. T. Chan, K. L. Monaco, R.-P. Wang and M. P. Winters,
Tetrahedron Lett., 1998, 39, 2933–2936.
C. Zhu and J. R. Falck, Adv. Synth. Catal., 2014, 356, 2395–
2410.
Z. Zheng, M. K. Elmkaddem, C. Fischmeister, T. Roisnel, C.
M. Thomas, J.-F. Carpentier and J.-L. Renaud, New J. Chem.,
2008, 32, 2150.
31
32
33
34
7
A. Del Grosso, P. J. Singleton, C. A. Muryn and M. J.
Ingleson, Angew. Chem., Int. Ed., 2011, 50, 2102–2106.
A. Prokofjevs, J. W. Kampf and E. Vedejs, Angew. Chem.,
Int. Ed., 2011, 50, 2098–2101.
8
9
A. Prokofjevs and E. Vedejs, J. Am. Chem. Soc., 2011, 133,
20056–20059.
35
36
37
10
11
T. Stahl, K. Müther, Y. Ohki, K. Tatsumi and M. Oestreich, J.
Am. Chem. Soc., 2013, 135, 10978–10981.
V. Bagutski, A. Del Grosso, J. A. Carrillo, I. A. Cade, M. D.
Helm, J. R. Lawson, P. J. Singleton, S. A. Solomon, T.
Marcelli and M. J. Ingleson, J. Am. Chem. Soc., 2013, 135,
474–487.
38
39
40
41
42
12
A. Del Grosso, J. Ayuso Carrillo and M. J. Ingleson, Chem.
Commun., 2015, 51, 2878–2881.
13
14
M. Ingleson, Synlett, 2012, 23, 1411–1415.
J. F. Hartwig and M. A. Larsen, ACS Cent. Sci., 2016, 2, 281–
292.
15
16
17
18
19
I. A. I. Mkhalid, J. H. Barnard, T. B. Marder, J. M. Murphy
and J. F. Hartwig, Chem. Rev., 2010, 110, 890–931.
T. Ishiyama, J. Takagi, K. Ishida, N. Miyaura, N. R. Anastasi
and J. F. Hartwig, J. Am. Chem. Soc., 2002, 124, 390–391.
J.-Y. Cho, M. K. Tse, D. Holmes, R. E. Maleczka and M. R.
Smith, Science, 2002, 295, 305–308.
Y. Saito, Y. Segawa and K. Itami, J. Am. Chem. Soc., 2015,
137, 5193–5198.
H. Tajuddin, P. Harrisson, B. Bitterlich, J. C. Collings, N. Sim,
A. S. Batsanov, M. S. Cheung, S. Kawamorita, A. C. Maxwell,
L. Shukla, J. Morris, Z. Lin, T. B. Marder and P. G. Steel,
Chem. Sci., 2012, 3, 3505–3515.
43
44
45
46
47
48
49
50
20
21
22
T. Furukawa, M. Tobisu and N. Chatani, J. Am. Chem. Soc.,
2015, 137, 12211–12214.
J. Takaya, S. Ito, H. Nomoto, N. Saito, N. Kirai and N.
Iwasawa, Chem. Commun., 2015, 51, 17662–17665.
S. Shimada, A. S. Batsanov, J. A. K. Howard and T. B.
Marder, Angew. Chem., Int. Ed., 2001, 40, 2168–2171.
Y. L. Liu, G. Kehr, C. G. Daniliuc and G. Erker, Chem. - Eur. J.,
2017, 23, 12141–12144.
S. Zhang, Y. Han, J. He and Y. Zhang, J. Org. Chem., 2018,
83, 1377–1386.
S. Chen, B. Li, X. Wang, Y. Huang, J. Li, H. Zhu, L. Zhao, G.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 9
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 10 of 12
ARTICLE
Journal Name
Frenking and H. W. Roesky, Chem. – A Eur. J., 2017, 23,
13633–13637.
V. Iashin, K. Chernichenko, I. Pápai and T. Repo, Angew.
Chem., Int. Ed., 2016, 55, 14146–14150.
Q. Zhong, S. Qin, Y. Yin, J. Hu and H. Zhang, Angew. Chem.,
2018, 130, 15107–15111.
Commun., 2017, 53, 7262–7265.
W.-M. Wan, A. W. Baggett, F. Cheng, H. Lin, S.-Y. Liu and F.
Jäkle, Chem. Commun., 2016, 52, 13616–13619.
B. Thiedemann, P. J. Gliese, J. Hoffmann, P. G. Lawrence, F.
D. Sönnichsen and A. Staubitz, Chem. Commun., 2017, 53,
7258–7261.
View Article Online
DOI: 10.1039/C9DT00484J
77
78
51
52
53
54
55
56
A. M. Mfuh, J. D. Doyle, B. Chhetri, H. D. Arman and O. V
Larionov, J. Am. Chem. Soc., 2016, 138, 2985–2988.
J. S. McGough, J. Cid and M. J. Ingleson, Chem. - Eur. J.,
2017, 23, 8180–8184.
M.-A. Légaré, É. Rochette, J. Légaré Lavergne, N. Bouchard
and F.-G. Fontaine, Chem. Commun., 2016, 52, 5387–5390.
M. V. Zakharova, N. Masoumifard, Y. Hu, J. Han, F. Kleitz
and F.-G. Fontaine, ACS Appl. Mater. Interfaces, 2018, 10,
13199–13210.
M. V. Zakharova, F. Kleitz and F.-G. Fontaine, Dalton Trans.,
2017, 46, 3864–3876.
K. C. Szeto, W. Sahyoun, N. Merle, J. L. Castelbou, N.
Popoff, F. Lefebvre, J. Raynaud, C. Godard, C. Claver, L.
Delevoye, R. M. Gauvin and M. Taoufik, Catal. Sci. Technol.,
2016, 6, 882–889.
79
80
81
82
83
84
85
86
M. Hong, J. Chen and E. Y.-X. Chen, Chem. Rev., 2018, 118,
10551–10616.
Y. Bai, J. He and Y. Zhang, Angew. Chem., Int. Ed., 2018, 57,
17230–17234.
M. Trunk, J. F. Teichert and A. Thomas, J. Am. Chem. Soc.,
2017, 139, 3615–3618.
M. Wang, F. Nudelman, R. R. Matthes and M. P. Shaver, J.
Am. Chem. Soc., 2017, 139, 14232–14236.
F. Vidal, H. Lin, C. Morales and F. Jäkle, Molecules, 2018,
23, 405.
L. Chen, R. Liu and Q. Yan, Angew. Chem., Int. Ed., 2018, 57,
9336–9340.
B. Das, K. Venkateswarlu, A. Majhi, V. Siddaiah and K. R.
Reddy, J. Mol. Catal. A: Chem., 2007, 267, 30–33.
G. A. Molander and D. L. Sandrock, Curr. Opin. Drug
Discovery Dev., 2009, 12, 811–823.
G. A. Molander and J. Ham, Org. Lett., 2006, 8, 2031–2034.
H. R. Kricheldorf, O. Nuyken and G. Swift, Handbook of
Polymer Synthesis, CRC Press, Boca Raton, 2004.
F. Cheng and F. Jäkle, Polym. Chem., 2011, 2, 2122–2132.
J. N. Cambre, D. Roy, S. R. Gondi and B. S. Sumerlin, J. Am.
Chem. Soc., 2007, 129, 10348–10349.
57
58
59
60
61
62
63
64
65
66
67
X. Y. Sun, B. Li, T. F. Liu, J. Song and D. S. Su, Phys. Chem.
Chem. Phys., 2016, 18, 11120–11124.
87
88
J. Y. Xing, J. C. Buffet, N. H. Rees, P. Nørby and D. O’Hare,
Chem. Commun., 2016, 52, 10478–10481.
K. K. Ghuman, L. B. Hoch, T. E. Wood, C. Mims, C. V. Singh
and G. A. Ozin, ACS Catal., 2016, 6, 5764–5770.
Y. Ma, S. Zhang, C.-R. Chang, Z.-Q. Huang, J. C. Ho and Y.
Qu, Chem. Soc. Rev., 2018, 47, 5541–5553.
P. Vishnoi, U. Gupta, R. Pandey and C. N. R. Rao, J. Mater.
Chem. A, 2019, DOI:10.1039/C8TA08497A.
Y. Qin, G. Cheng, A. Sundararaman and F. Jäkle, J. Am.
Chem. Soc., 2002, 124, 12672–12673.
J. Pellon, L. H. Schwind, M. J. Guinard and W. M. Thomas, J.
Polym. Sci., 1961, 55, 161–167.
Y. Qin, G. Cheng, O. Achara, K. Parab and F. Jäkle,
Macromolecules, 2004, 37, 7123–7131.
Y. Ren and F. Jäkle, in Main Group Strategies towards
Functional Hybrid Materials, eds. F. Jäkle and T.
Baumgartner, John Wiley & Sons, Ltd, Chichester, UK,
2018, pp. 79–110.
W. L. A. Brooks and B. S. Sumerlin, Chem. Rev., 2016, 116,
1375–1397.
Y. Chen, W. Wang, D. Wu, M. Nagao, D. G. Hall, T. Thundat
and R. Narain, Biomacromolecules, 2018, 19, 596–605.
A. Lik, L. Fritze, L. Müller and H. Helten, J. Am. Chem. Soc.,
2017, 139, 5692–5695.
F. Cheng and F. Jäkle, Chem. Commun., 2010, 46, 3717.
F. Liguori, S. Coiai, E. Passaglia and P. Barbaro,
Macromolecules, 2013, 46, 5423–5433.
M. S. Masri, F. W. Reuter and M. Friedman, J. Appl. Polym.
Sci., 1974, 18, 675–681.
R. J. Booth and J. C. Hodges, J. Am. Chem. Soc., 1997, 119,
4882–4886.
89
90
91
92
93
94
G. Vancoillie, S. Pelz, E. Holder and R. Hoogenboom, Polym.
Chem., 2012, 3, 1726–1729.
Y. Qin, V. Sukul, D. Pagakos, C. Cui and F. Jäkle,
Macromolecules, 2005, 38, 8987–8990.
J. Wang, B. Jin, N. Wang, T. Peng, X. Li, Y. Luo and S. Wang,
Macromolecules, 2017, 50, 4629–4638.
A. V. Radchenko, S. V. Kostjuk, I. V. Vasilenko, F.
Ganachaud and F. N. Kaputsky, Eur. Polym. J., 2007, 43,
2576–2583.
M. R. Buchmeiser, Polymer, 2007, 48, 2187–2198.
C. Viklund, F. Svec, J. M. J. Fréchet and K. Irgum, Chem.
Mater., 1996, 8, 744–750.
A. Goto and T. Fukuda, Prog. Polym. Sci., 2004, 29, 329–
385.
Q. Sun, Z. Dai, X. Meng and F.-S. Xiao, Chem. Soc. Rev.,
2015, 44, 6018–6034.
É. Rochette, H. Boutin and F. G. Fontaine, Organometallics,
2017, 36, 2870–2876.
A. Jayaraman, L. C. Misal Castro, V. Desrosiers and F.-G.
Fontaine, Chem. Sci., 2018, 9, 5057–5063.
E. Rochette and F.-G. Fontaine, ChemrXiv, 2018 ,
DOI:10.26434/chemrxiv.7354331.v1.
95
96
97
68
69
70
98
99
100
101
102
103
71
72
73
74
75
76
Bruker, APEX II, Bruker AXS Inc., Madison, Wisconsin, USA,
2017.
Bruker, SAINT and SADABS, Bruker AXS Inc., Madison,
Wisconsin, USA, 2017..
G. M. Sheldrick, Acta Cryst., 2015, C71, 3–8.
O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard
and H. Puschmann, J. Appl. Crystallogr., 2009, 42, 339–341.
T. K. Kyoung, J. J. L. M. Cornelissen, R. J. M. Nolte and J. C.
M. Van Hest, J. Am. Chem. Soc., 2009, 131, 13908–13909.
H. L. van de Wouw, J. Y. Lee and R. S. Klausen, Chem.
104
105
10 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 11 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
View Article Online
DOI: 10.1039/C9DT00484J
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 11
Please do not adjust margins

Dalton Transactions
Page 12 of 12
View Article Online
DOI: 10.1039/C9DT00484J
The synthesis and the activity of the first polymeric frustrated Lewis pairs for the borylation of
heteroarenes is reported.