A convenient and clean synthetic method for borasiloxanes by Pd-catalysed reaction of silanols with diborons

Article abstract of DOI:10.1039/c7cc02420g

Selective O-borylation of silanols with diborons took place in the presence of Pd catalysts to give the corresponding boryl silyl ethers in high yields.

Full text of DOI:10.1039/c7cc02420g

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Marilyn M. Olmstead, Alan L. Balch, Josep M. Poblet, Luis Echegoyenet al.
Reactivity differences of Sc3N@C2n (2n 68 and 80). Synthesis of the
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DOI: 10.1039/C7CC02420G
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A convenient and clean synthetic method for borasiloxanes by Pd-
catalysed reaction of silanols with diborons†
Aya Yoshimura,‡ Michiyo Yoshinaga, Hiroshi Yamashita,* Masayasu Igarashi, Shigeru Shimada
Received 00th January 20xx,
Accepted 00th January 20xx
and Kazuhiko Sato
DOI: 10.1039/x0xx00000x
www.rsc.org/
Selective O-borylation of silanols with diborons took place in the
presence of Pd catalysts to give the corresponding boryl sily
ethers in high yields.
reactions
OH
Conventional
3SiCl
a)
R
3Si-O-BR2
R
R
R
R
R
2BCl
R2B
R
3Si OH
3SiOR
2BOH
co- and
Si-O-Si
undesirble
byproduct
HCl,
3SiOH
R2BH
Poly(borosiloxane)s are valuable chemicals in materials
chemistry because of their excellent heat resistance and other
unique properties applicable to chemical sensors, effective
electrolyte additives, ceramic precursors, etc.1 The backbones
of poly(borosiloxane)s consist of Si-O-B linkages. Therefore,
efficient and selective synthetic methods of Si-O-B bonds are
very important in the synthesis of poly(borosiloxane)s.
Conventional methods for the preparation of Si-O-B bonds are
based on the condensation of hydroxyboranes with silane
derivatives such as chlorosilanes,2 chlorosiloxanes,3
alkoxysilanes1g,4 and silanols,1a,b,d,5 or condensation of silanols
with boron derivatives such as chloroboranes,1a,6
H
2O,
Transition metal catalysed reactions
b)
work
O
b-1) Marciniec's
O
B
O
[Ru]
R
R
3Si
3SiOH
B
O
O
toluene
60-130o 3-24 h
C,
work
b-2) Nakazawa's
=
Mo,
Fe)
W,
[M]
(M
R
3SiH
H
2O
R
3Si-O-Bpin
O(Bpin)2
toluene
25o 20 h
C,
ν
h
,
work
H
b-3) Gunanathan's
[Ru]
R
3Si-O-Bpin
H2
R
3SiH
2O
HBpin
toluene
alkoxyboranes1a,7 and
a
hydroborane6a,8 (Scheme 1a).
125o 24 h
C,
However, these classical methods have some drawbacks, i.e.
the use of toxic and/or moisture-sensitive starting materials,
harsh reaction conditions, low selectivity for the desired
products and formation of undesired co- and byproducts such
as corrosive HCl, azeotropic H2O, hardly separatable
disiloxanes, etc. Therefore, selective and clean Si-O-B bond-
forming reaction using low-toxic and easily-handled starting
materials has been desired.
Recently, to solve the problems of the conventional
methods, some catalytic Si-O-B bond-forming reactions
have been reported using silanols or hydrosilanes (Scheme 1b).
For the reactions of monosilanols, Marciniec reported that Ru
complexes catalysed the O-borylation of silanols with
vinylboronates to produce Si-O-B compounds in high yields
(Scheme 1b-1).9 For a poly(borosiloxane) synthesis, Matsumi
This Work
c)
O
B
O
cat.
Pd
O
B
O
O
B
O
R1R2R
3Si
R1R2R3
H2
SiOH
O
easily available diboron
reagents
Scheme 1 The
Si-O-B bond-forming
processes.
recently reported effective polycondensation with ArBH2 (Ar =
mesityl) in the presence of transition metal complexes.1h
Regarding the use of hydrosilanes, selective Si-O-B bond
formation in the photoreaction with bisboryloxide/boroxine
catalysed by Mo, W and Fe complexes was achieved by
Nakazawa (Scheme 1b-2).10 Also, Gunanathan demonstrated
selective synthesis of Si-O-B bond by Ru-catalysed reaction of
hydroboranes (or boronic acids) with silanes and water
(Scheme 1b-3).11 In addition, Rubinsztajn presented
a
poly(borosiloxane) synthesis by B(C6F5)3-catalysed reaction
between Ph2SiH2 and B(OMe)3 with liberation of methane.12
The precedent results prompted us to examine Si-O-B
bond-forming reactions using easily available diboron reagents
National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1,
Higashi, Tsukuba, Ibaraki 305-8565, Japan.
* E-mail: hiro-yamashita@aist.go.jp
†
Electronic Supplementary Information (ESI) available: General information,
detailed experimental procedures, characterization data and copies of 1H, 13C, 11B such as bis(pinacolato)diboron (B2pin2).13 Carefully searching
and 29Si NMR spectra of the products. See DOI: 10.1039/x0xx00000x
the literatures, we could find only one such example; Ohmura
and Suginome mentioned the formation of Me3SiOBpin from
‡
Present address: Department of Applied Chemistry, Graduate School of Science
and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577,
Japan.
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Me3SiOH and B2pin2 catalysed by [Ir(OMe)(cod)]2 (cod = 1,5- oC for 4 h (entry 4), but decreasing the reaction temperature to
View Article Online
o
DOI: 10.1039/C7CC02420G
cyclooctadiene) in the footnote of their paper on the Ir- 25 C led to no generation of the product (entry 5).
catalysed C(sp3)-H borylation of methylchlorosilanes.14 Herein, PdCl2(PhCN)2 mainly catalysed unfavorable formation of a
we present a Pd-catalysed selective Si-O-B bond-forming disiloxane 2a, and 1a was obtained in only 11% yield (entry 6).
reaction by dehydrogenative O-borylation of a variety of PdCl2(PPh3)2 and Pd2(dba)3 (dba = dibenzylideneacetone) did
silanols with easily available diborons (Scheme 1c). The not catalyse the reaction at all (entries 7 and 8), and addition
reaction can not only efficiently take place under mild of PPh3 to Pd2(dba)3 did not affect the results (entry 9). In the
conditions, but also proceed with generation of only hydrogen case of PdCl2, the reaction proceeded unselectively to give 1a
gas, i.e. without generation of any liquid or solid waste.
and 2a in 29% and 36% yields, respectively (entry 10). As to
Firstly, to choose effective catalysts, Et3SiOH was allowed other transition metal complexes, Pt(PPh3)4, PtCl2(PhCN)2, and
to react with B2pin2 in the presence of various transition metal RhCl(PPh3)3 gave 1a in low to moderate yields (entries 11-13).
compounds (Table 1). As the result, we found that Et3SiOH (1.0 As previously reported,14 [Ir(OMe)(cod)]2 also gave 1a in 64%
mmol) reacted with B2pin2 (0.5 mmol) in the presence of Pd yield along with a small amount of 2a in the presence of
acetate, Pd3(OAc)5(NO2) or Pd3(OAc)6 (0.5 mol% Pd based on 3,4,7,8-tetramethyl-1,10-phenanthroline as a ligand (entry 14).
Et3SiOH), or Pd(PPh3)4 (1 mol%) at 25 oC for 3 h under nitrogen Cu(OAc)2, Ni(cod)2 and Ni(acac)2 also catalysed the reaction
atmosphere to produce the desired product bearing Si-O-B selectively (entries 15-17). But the yields of 1a obtained by
bond 1a in 94%, 90% or 93% yield, respectively, without any these Pt, Rh, Ir, Cu and Ni catalysts were lower than those by
byproducts (entries 1-3). In this reaction, B2pin2 reacted with the Pd catalysts. In the series of group 10 metal complexes, on
two equivalents of Et3SiOH along with coproduction of the basis of the yields of 1a and the reaction conditions, the
hydrogen. Indeed, when Et3SiOH was added to a mixture of order of the catalyst activity is estimated as follows:
B2pin2 and Pd(OAc)2 catalyst, vigorous hydrogen gas evolution Pd3(OAc)5(NO2) ~ Pd3(OAc)6 ~ Pd(PPh3)4 > Pt(PPh3)4 > Pd(acac)2
was observed after an induction period of several minutes. > PtCl2(PhCN)2 > Ni(acac)2.15 In contrast, when strong Lewis
Regarding the Pd acetate, commercially available so-called acids such as Sc(OTf)3 (Tf = SO2CF3) and FeCl3 were used as the
Pd(OAc)2 consists of trinuclear Pd complexes such as Pd3(OAc)6 catalysts, the formation of the disiloxane 2a took place
and/or Pd3(OAc)5(NO2) (see ESI). Both forms are active in this selectively without producing 1a under similar reaction
reaction, and gave 1a in high yields. For other Pd complexes, conditions (entries 18 and 19). In the absence of catalysts, the
Pd(acac)2 (acac = acetylacetonate) catalysed the reaction at 80 reaction did not proceed at all (entry 20).
This Pd-catalyzed O-borylation was applicable to other
silanols and diborons. As shown in Table 2, a variety of silanols
were O-borylated by diborons in the presence of a catalytic
amount of Pd acetate, producing the corresponding
Table 1 Catalytic O-borylation of Et3SiOH with B2pin2
Catalyst (0.5-26 mol%)
B2pin2
2 Et3Si-O-Bpin Et3Si O SiEt3
2 Et3SiOH
1.0 mmol
compounds bearing Si-O-B bond
1 in high yields. Various
neat
2a
1a
0.5 mmol
silanols including Et3SiOH, PhMe2SiOH and Ph3SiOH could
Yield (%)a
Reaction
conditions
Catalyst (mol% metal)
Entry
1a
2a
Table 2 Pd acetate-catalysed O-borylation of silanols with diboronsa
25oC, 3 h
25oC, 3 h
25oC, 3 h
80oC, 4 h
25oC, 3 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
25oC, 3 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
80oC, 4 h
1
2
3
4
5
6
7
8
Pd3(OAc)5(NO2) (0.5)
Pd3(OAc)6 (0.5)
Pd(PPh3)4 (1)
94
90
93
66
0
0
0
Pd acetate 1mol%
R1R2R3Si-O-B(OR4)2
B2(OR4)4
R1R2R3SiOH
1.0 mmol
1
0
0.5-1.0 mmol
Pd(acac)2 (1)
0
O
O
O
O
Pd(acac)2 (3)
0
Et3Si
O
B
PhMe2Si
O
B
Ph3Si
O
B
O
O
PdCl2(PhCN)2 (3)
PdCl2(PPh3)2 (3)
11
0
82
3
1a
1b
1c
94% (81%)
Pd2(dba)3 (5)
Pd2(dba)3 (5)
PdCl2 (26)
99% (92%)
95% (84%)
0
0
0
0
9b
O
Ph
O
O
O
O
O
(BuOt)3Si
1d
O
B
Me3Si
O
B
10
29
36
B
O Si
Ph
1f
O B
O
O
Pt(PPh3)4 (1)
11
12
13
56
40
18
64
0
7
0
1
1e
PtCl2(PhCN)2 (10)
RhCl(PPh3)3 (4)
[Ir(OMe)(cod)]2 (5)
98% (64%)
99% (83%)
97% (86%)
14c
15
16
17
18
19
20
O
O
O
B
O
Et3Si
O
B
Et3Si
O
B
Et3Si
O
Cu(OAc)2 (15)
Ni(cod)2 (8)
Ni(acac)2 (10)
Sc(OTf)3 (7)
FeCl3 (19)
none
79
15
31
0
0
0
O
O
1g
1h
1i
94% (77%)
98% (85%)
99% (94%)
0
a Reaction Conditions: 1a cat 0.5 mol%, B2pin2 0.55 mmol, 25oC, 3 h; 1b B2pin2 0.54
mmol, 25oC, 3 h; 1c B2pin2 0.58 mmol, THF 0.25 mL, 80oC, 4 h; 1d B2pin2 1.0 mmol,
THF 0.25 mL, 80oC, 4 h; 1e B2pin2 1.0 mmol, 25oC, 4 h; 1f B2pin2 2.0 mmol (2equiv.),
THF 0.25 mL, 80oC, 4 h; 1g B2neop2 1.0 mmol, 80oC, 4 h; 1h B2hexl2 1.0 mmol, 80oC,
4 h; 1i B2cat2 1.0 mmol, 25oC, 3 h. The yields were determined by 29Si NMR. Isolated
yields are shown in parentheses.
99
99
0
0
0
a Determined by 29Si NMR using PhMe3Si as an internal standard.
b PPh3 (5 mol% based on Si-OH bond) was added.
c 3,4,7,8-Tetramethyl-1,10-phenanthroline (10 mol%) was added.
2 | J. Name., 2012, 00, 1-3
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react with B2pin2 to give the corresponding Si-O-B compounds. would be involved in the catalytic cycle, althoughVwieweAhrtaicvleeOnnlionet
The reaction of a trialkoxysilanol, (tBuO)3SiOH, with B2pin2 also been able to observe the Pd specie, presumably because of its
DOI: 10.1039/C7CC02420G
smoothly proceeded to provide 1d quantitatively. Me3SiOH high reactivity. Coordination of a silanol (R3SiOH) to the Pd
also reacted with B2pin2 to give the expected product 1e in species
64% yields. Ph2Si(OH)2 bearing two Si-OH group was smoothly Hydrogen atom transfer from R3SiOH to the Pd center forms
O-borylated with B2pin2, giving the corresponding product 1f in an [Pd]-H species along with production of R3SiOBpin. Then,
good yield. Furthermore, the present Pd-catalysed O- another R3SiOH would interact with the Pd species to give a
with release of hydrogen. Attack of B2pin2
, possibly via a four-centered intermediate
, would afford another molecule of R3SiOBpin with
bis(catecholato)diboron (B2cat2) also reacted with Et3SiOH to regeneration of the Pd species A 19
produce the corresponding compounds (1g ). When the To get information on the reaction mechanism, we
starting silanols are liquid compounds (Et3SiOH, PhMe2SiOH), examined
A would give a four-centered intermediate species B.
C
C
borylation was applicable to other diboron compounds. In [Pd]-OSiR3 species
addition to B2pin2, bis(neopentyl glycolato)diboron (B2neop2), to the Pd species
D
D
bis(hexylene
glycolato)diboron
(B2hexyl2)
and species E
.
-
i
a
stoichiometric reaction of Pd acetate
o
the reactions could be conducted without any solvent, (Pd3(OAc)5(NO2)) with B2pin2 and Et3SiOH at 25 C (eqn (1)).
providing an environmentally benign process. These reaction The Pd acetate was mixed with B2pin2 in THF-d8 and kept at 25
were very efficient, and the products 1a-h were formed in oC for 3 h. Addition of Et3SiOH to the resulting mixture gave
excellent NMR yields (
isolated in high yields by simple purification processes such as unreacted Et3SiOH. In contrast, when B2pin2 was added to a
short-path distillation under reduced pressures. mixture of stoichiometric amount of the Pd acetate and
possible reaction mechanism for the present O- Et3SiOH, the formation of 1a was accompanied by
≥94%). In addition, 1a-h could be easily the desired product Et3SiOBpin 1a in 68% yield along with
A
a
borylation of silanols (R3SiOH) with a diboron (B2pin2) is shown considerable amount of a disiloxane (Et3SiOSiEt3); the yields of
in Scheme 2. An active Pd species would be generated by 1a and Et3SiOSiEt3 were 73% and 26%, respectively (eqn (2)). In
transmetalation between the Pd acetate ([Pd]-OAc) and B2pin2, the present Pd catalysis, such disiloxane formation was not
leading to a borylpalladium species [Pd]-Bpin A. Formation of observed at all. This indicates that the interaction of the Pd
similar [Pd]-Bpin species has been suggested in the Pd acetate- acetate with B2pin2 in the initial stage is an important process
catalysed reaction of N-heteroaromatics with water in the leading to the generation of active Pd species, although the
presence of B2pin216,17 and also in the Pd-catalysed reactions of structure has not been confirmed yet.
aryl halides with B2pin2 in the presence of potassium acetate.18
In conclusion, we have disclosed a new simple method for
Therefore, we suppose that some borylpalladium species the preparation of Si-O-B compounds by using easily available
silanols and diboron reagents. The successful use of diborons
OAc
[Pd]
coupled with Pd catalysts for borasiloxane synthesis is most
unique point in the comparison with the previously reported
methods using hydroxyboranes, hydroboranes or boroxanes as
boron sources. The high activity of the commonly-used air-
stable Pd acetate catalyst is also noteworthy in the practical
viewpoint. Since the Pd catalysis is facile and clean, the
present method would have a potential applicability to
modification of silanol group-containing materials, such as
silicone polymers, to improve their physical properties and/or
to add new chemical properties based on the boron moieties.
Further studies on the application of the present Pd catalysis
and other reactions for the formation of Si-O-B compounds are
under way.
B
2pin2
AcOBpin
[Pd] Bpin
R
3SiOBpin
R
3SiOH
A
[Pd] Bpin
OSiR3
Bpin
[Pd]
H
O SiR3
B
pin
B
E
R
3SiOBpin
B
2pin2
H
OSiR3
[Pd]
[Pd]
H2
C
D
This work was supported by the "Development of
Innovative Catalytic Processes for Organosilicon Functional
Materials" project (the project leader: K. Sato) from the New
Energy and Industrial Technology Development Organization
(NEDO).
R
3SiOH
2
Scheme
A
possible
mechanism.
B2pin2
0.05 mmol
Et3SiOH
0.1 mmol
(1)
Et3Si-O-Bpin
Pd3(OAc)5(NO2)
0.05 mmol Pd
1a
68%
THF-d8 (30 µL)
25oC, 3 h
Notes and references
B2pin2
0.05 mmol
Et3SiOH
0.05 mmol
1
For instance, (a) V. F. Gridina, A. L. Klebanskii, L. P.
Dorofeyenko and L. Y. Krupnova, Polym. Sci. U.S.S.R., 1968,
2196 and references therein; (b) H. S. J. Behbehani, B. J.
Brisdon and B. McEnaney, Polym. Adv. Technol., 1994,
(2)
Et3Si-O-Bpin
Et3Si-O-SiEt3
26%
Pd3(OAc)5(NO2)
0.05 mmol Pd
9
,
THF-d8 (30 µL)
25oC, 3 h
1a
73%
5
,
653; (c) O. G. Khelevina and A. S. Malyasova, Russ. J. Appl.
Chem., 2014, 87, 480; (d) W. Liu, M. Pink and D. Lee, J. Am.
This journal is © The Royal Society of Chemistry 20xx
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Chem. Soc., 2009, 131, 8703; (e) Y.-K. Han, J. Yoo and T. Yim, 17 (a) In our case, when a Pd acetate, Pd3(OAc)5(NO2) (0.05
Electrochim. Acta., 2016, 215, 455; (f) J. Li, L. Xing, R. Zhang,
M. Chen, Z. Wang, M. Xu and W. Li, Power Sources, 2015,
285, 360; (g) M. A. Schiavon, N. A. Armelin and I. V. P.
Yoshida, Mater. Chem. Phys., 2008, 112, 1047; (h) P. Puneet,
mmol Pd), was treated with B2pin2 (0.05 mmoVl)iewinArCtic6lDe 6On(l3in0e
µ
L) at 25 oC for 3 h, new singlet 1H DNOMI:R10.s1i0g3n9a/lCs7,CpCr0o2b4a2b0lGy
due to AcO-Bpin, appeared at 1.01 (CH3 of Bpin) and 1.56
(CH3 of AcO) ppm, which were well consistent with the
reported values.17b (b) C. J. Pell and O. V. Ozerov, Inorg.
R. Vedarajan and N. Matsumi, ACS Sens., 2016,
(a) F.-E. Hong, C. W. Eigenbrot and T. P. Fehlner, J. Am.
Chem. Soc., 1989, 111 949; (b) A.-F. Mingotaud, V. 18 (a) T. Ishiyama, M. Murata and N. Miyaura, J. Org. Chem.,
roguez, and A. Soum, J. Organomet. Chem., 1998, 560
109; (c) L. A. Neville, T. R. Spalding and G. Ferguson, Angew.
1, 1198.
2
Chem. Front., 2015, 2, 720.
,
H
é
,
1995, 60, 7508; (b) M. Sumimoto, N. Iwane, T. Takahama and
S. Sakaki, J. Am. Chem. Soc., 2004, 126, 10457.
Chem. Int. Ed., 2000, 39, 3598; (d) M. A. Beckett, M. P. 19 Although the mechanism of the catalysis has not been
Rugen-Hankey and K. S. Varma, Polyhedron, 2003, 22, 3333;
(e) E. A. Makarova, S. Shimizu, A. Matsuda, E. A. Luk’yanets
and N. Kobayashi, Chem. Commun., 2008, 2109.
D. A. Foucher, A. J. Lough and I. Manners, Inorg. Chem.,
1992, 31, 3034.
elucidated yet, transmetalation process between the [Pd]-
OSiR3 and the B-B bond seems to be a kinetically relevant
step. The hypothesis is consistent with the observation that
the reaction of sterically less-hindered B2cat2 has been much
faster than that of B2pin2.
3
4
5
K. A. Andrianov and T. V. Vasil’eva, Dokl. Chem., 1966, 168
,
582.
(a) G. Ferguson and A. J. Lough, Acta. Cryst., 1990, C46, 1252;
(b) B. J. Brisdon, M. F. Mahon, K. C. Molly and P. J. Schofield,
J. Organomet. Chem., 1992, 436, 11; (c) D. Murphy, J. P.
Sheehan, T. R. Spalding, G. Ferguson, A. J. Lough and J. F.
Gallagher, J. Mater. Chem., 1993, 3, 1275; (d) G. Ferguson, B.
J. O’Leary, D. M. Murphy and T. R. Spalding, J. Organomet.
Chem., 1996, 526, 195; (e) B. J. O’Leary, T. R. Spalding and G.
Ferguson, Polyhedron, 1999, 18, 3135; (f) M. A. Beckett, D. E.
Hibbs, M. B. Hursthouse, K. M. A. Malik, P. Owen and K. S.
Varma, J. Organomet. Chem., 2000, 595
, 241; (g) G.
Ferguson, S. E. Lawrence, L. A. Neville, B. J. O’Leary and T. R.
Spalding, Polyhedron, 2007, 26, 2482; (h) M. Pascu, A. Ruggi,
R. Scopelliti and K. Severin, Chem. Commun., 2013, 49, 45; (i)
M. A. Beckett, P. Owen and K. S. Varma, J. Organomet.
Chem., 1999, 588, 107.
(a) R. A. Metcalfe, D. I. Kreller, J. Tian, H. Kim, N. J. Taylor, J.
F. Corrigan and S. Collins, Organometallics, 2002, 21, 1719;
(b) K. Thieme, S. C. Bourke, J. Zheng, M. J. MacLachlan, F.
Zamanian, A. J. Lough and I. Manners, Can. J. Chem., 2002,
80, 1469; (c) Z. Zhao, A. N. Cammidge and M. J. Cook, Chem.
Commun., 2009, 7530.
6
7
8
(a) I. Kijima, T. Yamamoto and Y. Abe, Bull. Chem. Soc. Jpn.,
1971, 44, 3193; (b) K. L. Fujdala, A. G. Oliver, F. J. Hollander
and T. D. Tilley, Inorg. Chem., 2003, 42, 1140.
C. Kleeberg, M. S. Cheung, Z. Lin and T. B. Marder, J. Am.
Chem. Soc., 2011, 133, 19060. Formation of PhMe2Si-O-Bpin
from HBpin (pin = pinacolato) and PhMe2SiOH was described
in the supporting information (page S13) of the paper.
B. Marciniec and J. Walkowiak, Chem. Commun., 2008, 2695.
9
10 M. Ito, M. Itazaki and H. Nakazawa, J. Am. Chem. Soc., 2014,
136, 6183.
11 B. Chatterjee and C. Gunanathan, Chem. Commun., 2017, 53
,
2515.
12 S. Rubinsztajn, J. Inorg. Organomet. Polym., 2014, 2, 1092.
13 Diborons are versatile useful reagents. For recent reviews on
diboron chemistry, (a) E. C. Neeve, S. J. Geier, I. A. I. Mkhalid,
S. A. Westcott and T. B. Marder, Chem. Rev., 2016, 116
,
9091; (b) A. B. Cuenca, R. Shishido, H. Ito and E. Fernández,
Chem. Soc. Rev., 2017, 46, 415. For borylation of C-H bonds
using diborons, (c) J. F. Hartwig, Acc. Chem. Res., 2012, 45,
864; (d) K. T. Smith, S. Berritt, M. González-Moreiras, S. Ahn,
M. R. Smith III, M.-H. Baik and D. J. Mindiola, Science, 2016,
351, 1424.
14 T. Ohmura, T. Torigoe and M. Suginome, J. Am. Chem. Soc.,
2012, 134, 17416 (Ref 20).
15 At the moment, the reason of the high activity and selectivity
observed for Pd acetate and Pd(PPh3)4 is not clear, and
further mechanistic study will be required to understand the
results.
16 Q. Xuan and Q. Song, Org. Lett., 2016, 18, 4250.
4 | J. Name., 2012, 00, 1-3
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