Amine-borane complexes: Air- and moisture-stable partners for palladium-catalyzed borylation of aryl bromides and chlorides

Article abstract of DOI:10.1002/adsc.201401153

A method for using amine-borane complexes directly in palladium catalyzed borylation has been developed. The reaction proceeds through the sequential formation of a boronium species followed by deprotonation leading to the aminoborane. This reagent is then directly used in the borylation process leading, after work-up, to various boronic acid derivatives. The reaction was applied to (hetero)aryl triflates, iodides, bromides and chlorides.

Full text of DOI:10.1002/adsc.201401153

COMMUNICATIONS
DOI: 10.1002/adsc.201401153
Amine–Borane Complexes: Air- and Moisture-Stable Partners for
Palladium-Catalyzed Borylation of Aryl Bromides and Chlorides
HØl›ne D. S. Guerrand,a Michel Vaultier,a Sandra Pinet,a
and Mathieu Pucheaulta,b,*
a
CNRS, UniversitØ de Bordeaux, ISM, UMR 5255, F-33405 Talence, France
Fax: (+33)-5-4000-6632; phone: (+33)-5-4000-6733; e-mail: m.pucheault@ism.u-bordeaux1.fr
ISM, 351 cours de la libØration, 33405 Talence Cedex, France
b
Received: December 12, 2014; Revised: February 16, 2015; Published online: March 24, 2015
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201401153.
Abstract: A method for using amine–borane com-
plexes directly in palladium catalyzed borylation
has been developed. The reaction proceeds through
the sequential formation of a boronium species fol-
lowed by deprotonation leading to the aminobor-
ane. This reagent is then directly used in the boryla-
tion process leading, after work-up, to various bor-
onic acid derivatives. The reaction was applied to
(hetero)aryl triflates, iodides, bromides and chlor-
ides.
where sterically hindered groups[5c] and chelating
groups[5d–g,i] are used to orientate the borylation.
Alternatively, Pd-,[6] Ni-,[7] Cu-,[8] or Zn[9]-catalyzed
borylations of aryl halides (I, Br) or sulfonates
have been described.[10] Few publications deal
with the metal-catalyzed borylation of aryl chlori-
des,[6c–j,n,o,q,u,7a,c–f,h,11] in particular of electron-poor un-
reactive aryl chlorides.[7e,f] Rh-catalyzed borylation of
nitriles[12] and Ni-catalyzed borylation of amides and
carbamates[13] through the cleavage of C CN, C N
and C O bonds have also been described. Very re-
À
À
À
Keywords: amine–borane complexes; aryl halides;
cently, transition metal-free borylation of aryl io-
dides[14] and metal-free borylation of amines,[15] via in
situ diazotization, have been studied. An elegant
metal-free borylation of aryl bromides using silylbor-
ane was published by Ito et al.[16] Unfortunately low
yields were obtained from relative inexpensive and
broadly available aryl chlorides.
À
boron; C B bond formation; homogeneous cataly-
sis
Arylboronic acids and their derivatives are very im-
In 2003, Vaultier et al. reported the Pd-catalyzed
portant compounds in organic chemistry, as chemical borylation of iodides and bromides using dialkylami-
intermediates or building blocks. Their use in transi- noboranes[17] as boron source. Recently, we extended
tion metal-catalyzed cross-coupling reactions can the scope of this reaction with sequential aminobory-
lead, for example, to carbon–carbon and carbon–het- lation/Suzuki–Miyaura cross-coupling reaction leading
eroatom bond formation. Traditionally arylboronic to non-symmetrical biaryl compounds.[18] and with the
acids and boronates are obtained from aryl halides (I, borylation of unactivated aryl chlorides in the pres-
Br) after metal-halogen exchange with lithium or ence of potassium iodide as additive.[19] Aryldiazoni-
magnesium and subsequent reaction with trialkoxy- um tetrafluoroborates can also participate in the bor-
boranes.[1] Although efficient, such conditions are not ylation process with aminoborane through the forma-
compatible with many functional groups (e.g., reac- tion of the aryl radical.[20] Overall, dialkylaminobor-
tive carbonyl, nitrile, etc.…) eventually requiring tedi- anes appeared to be very efficient reagents in boryla-
ous additional protection–deprotection steps. Since tion reactions. Indeed, resulting aminoarylboranes are
the late 1990s, transition metal-catalyzed borylation easily transformable in boronic acids, boronates or tri-
reactions have been developed considerably. Direct fluoroborate salts, depending on reaction work-
[2]
C H borylations of aromatics catalyzed mainly by up.[19,21] Only monomeric aminoboranes, typically (i-
À
Rh[3] and Ir[3a,4],have been reported using bispinacola- Pr)2NBH2, participate in the catalyzed borylation pro-
todiboron and pinacolborane as borylating agents.[2–5] cess. They are usually prepared by thermal decompo-
Mostly, mixture of regioisomers are obtained[5h,j] sition of the corresponding amine–borane complexes
except in the case of 1,3-disubstituted benzenes,[5a,b] or or by trimethylsilyl chloride treatment of lithium dia-
lkylaminoborohydrides.[22] Metal-catalyzed dehydro-
Adv. Synth. Catal. 2015, 357, 1167 – 1174
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1167

COMMUNICATIONS
HØl›ne D. S. Guerrand et al.
Scheme 1. Catalytic borylation with amine–borane com-
plexes.
genation of these complexes can also be used but re-
mains inefficient on sterically hindered amine–borane
complexes.[23] In all cases, the prepared aminoborane
is recovered before further use.
One of the downsides of this methodology stands in
the relative instability of the aminoborane. Indeed,
similarly to trialkoxyborane or dialkoxyborane, these
reagents are prone to fast hydrolysis and require dis-
tillation before use. On the contrary, amine–borane
complexes are obtained directly from dialkylamines
and a BH3 source[17b] or NaBH4[17b,24] and are relatively
air- and moisture-stable. As a precursor of aminobor-
anes, we tentatively used them in a dehydrogenation–
coupling sequence, but the efficiency was fairly low
with isolated yields limited to 50%.[24] Herein, we
wish to report our recent results concerning a practi-
cal, economic and efficient Pd-catalyzed borylation of
aryl halides using diisopropylamine–borane[25] as re-
agent (Scheme 1).
Figure 1. Preparation of diisopropylaminoborane: 11B NMR
monitoring (C6D6, 258C).
In 2006, Baker et al. described the use of acids to
catalyze the dehydrocoupling of ammonia–borane in
aminoborane via the boryl–ammonium intermediate
[H2B-NH3]+.[26] Later, cyclotriborazane [(NH2-BH2)3] ure 1b), characteristic of borylammonium intermedi-
was prepared by basic treatment of [BH2-NH3]Cl.[27] ate, is observed between À7 and À3 ppm depending
Thus we planned to generate the boryldiisopropylam- on the counter-anion (Cl, À6.7 ppm; OTf, À3.7 ppm;
monium salt from the corresponding amine–borane OMs, À4.1 ppm; SO4, À3.7 ppm as broad signal).
complex. Upon base addition, the aminoborane These results are consistent with those of Manners
would be generated in the reaction mixture. During who observed in 11B NMR, a downfield shift from
our study, our strategy was validated by Manners who À6.8 ppm to À2.2 ppm when the chloride substituent
reported the formation of methyl- and dimethylami- was replaced by triflate anion in borylmethylammoni-
noborane, as polymer and dimer, respectively, from um.[28] Complete disappearance of the amine–borane
borylammonium
salts
[RR’NH-BH2]+XÀ
[X= complex proceeded within 15 min except for
B(C6F5)3, OTf] or amine–chloroborane complexes CH3SO3H for which 5 h were required to obtained
RR’NH-BH2X.[28] Formation of MeNH=BH2 was a complete conversion. Then, addition of one equiva-
proven by 11B NMR spectroscopy monitoring of the lent of diisopropylamine led to the expected diisopro-
reaction at low temperature.
pylaminoborane (triplet at 35.5 ppm, Figure 1c)
In our case, diisopropylamine (DIPA) was chosen through deprotonation of the borylammonium. In the
as base to avoid refunctionalization of boron deriva- case of H2SO4, despite the formation of the borylam-
tives often occurring when amine mixtures are used. monium, no (i-Pr)2NBH2 was observed upon DIPA
We investigated
a series of acids (HCl, TFA, addition and only a broad signal at 28 ppm was ob-
MeSO3H and H2SO4) and monitored the reaction served and attributed to the formation of trivalent
using 11B NMR spectroscopy. Hence, to a solution of borane–sulfate oligomers.
diisopropylamine–borane complex (q at À20.4 ppm,
The borylammonium counter-anion influences the
Figure 1a) was added one equivalent of the studied acidity of the intermediate 2 resulting in strong varia-
acid. All acids were added in pure form, except HCl tion of the deprotonation efficiency. As mentioned by
which was used in Et2O. Upon reaction, a triplet (Fig- Manners,[28] the pKa is lowered by poorly coordinating
1168
asc.wiley-vch.de
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2015, 357, 1167 – 1174

COMMUNICATIONS
Amine–Borane Complexes: Air- and Moisture-Stable Partners
The one-pot dehydrogenation/arylation of diisopro-
pylamine–borane complex proceeds smoothly with
the aromatic iodide and triflate. In both cases, after
work-up and treatment with pinacol, the borylated
compound was isolated in 99% yield (entries 1 and 2,
Table 1). In case of bromo- and chloroanisoles, yields
in isolated products were lower, 70% and 64% re-
spectively (entries 3 and 5, Table 1). The presence of
diisopropylammonium chloride resulting from the for-
mation of aminoborane is detrimental in the coupling
process as it reacts with the DIPA. A simple filtration
before adding catalysts and substrate improved the
yields to 99% and 97%, respectively (entries 4 and 6,
Table 1).
Scheme 2. One-pot dehydrogenation/arylation of diisopro-
pylamine–borane with 4-bromoanisole.
substituents. As chloride has weaker interactions with
With the optimized conditions in hand, the sub-
boron than oxygenated anions, the proton on the NH strate scope of this reaction was examined with a vari-
group of 2a is the most acidic and leads to fast depro- ety of aryl bromides (Table 2). Obvious improvements
tonation (20 min). Similarly, the reactivity difference in yields were observed via this methodology com-
observed between triflate (5 h) 2b and methylsulfo- pared to our previous results via sequential dehydro-
nate 2c (16 h) is directly related to the decreased genation arylation of (i-Pr)2NH–BH3 with Pd nano-
binding of the oxygen atom induced by the trifluoro- particles[24] (Table 2). In general, the borylation of var-
methyl group.
ious aryl bromides occurred in good to excellent
After having generated in situ the boryldiisopropyl- yields from 1. Aryl bromides bearing an electron-do-
ammonium by HCl addition, we successively added nating group, such as methoxy, methyl or phenyl, af-
diisopropylamine, 4-methoxybenzyl bromide, and forded the corresponding pinacolboronate esters in
a catalytic amount of PdCl2(dppf) (Scheme 2). The high yields (Table 2 entries 1–4, 7 and 8).
mixture was heated to 808C and the reaction moni-
The borylation of 2-bromothiophene afforded 81%
tored by H and 11B NMR (see the Supporting Infor- of 5f (Table 2, entry 6) while the less reactive 3-regio-
mation). After 2 h 30 min, the characteristic triplet at isomer has been borylated with an acceptable yield of
35.5 ppm, in the 11B NMR spectrum, was replaced by 69% (Table 2, entry 5). Other heteroaromatics such as
a broad signal at 39 ppm indicating the formation of 3- and 5-bromobenzo[b]thiophenes were also borylat-
the aminoarylborane 4. The reaction was quenched ed efficiently (Table 2, entries 9 and 10) showing that
with deuterated methanol. After 1 h, the signal potential coordination of the boron center to the
at 39 ppm wholely disappeared leading unsurprisingly sulfur atom of these substrates was not detrimental.
to a mixture of corresponding methyl boronate
1
[Ar-B(OCD3)2, 28.1 ppm] and boroxine (20.7 ppm).
After transesterification with pinacol, the boronate 5a
was isolated in 69% yield.
Table 1. Sequential dehydrogenation–arylation of diisopro-
pylamine–borane 1.
Encouraged by this result, we carried on with the
borylation of anisoles substituted with various leaving
groups (X=I, Br, Cl, OTf) in the para position. Previ-
ously, aminoborane borylation conditions had been
optimized, and varied slightly depending on the
halide carried by the aromatic ring. Consequently,
borylations of 4-iodoanisole,[18] 4-anisyl triflate and 4-
bromoanisole were carried out using PdCl2(dppp) as
catalyst in toluene at 1108C.[17a,b] Diisopropylamine
was preferred to triethylamine in order to keep the
same base for the whole reaction sequence. Boryla-
tion of 4-chloroanisole was carried out with
Pd(OAc)2, XPhos as ligand and potassium iodide as
additive, in ethyl acetate at 508C, according to our
recent results on the borylation of aryl chlorides.[19a]
Triethylamine was kept as base since it has been
proved to be more efficient than diisopropylamine. A
solution of hydrochloric acid in ethyl acetate was
used to generate the amine boronium.
Entry
X
Procedure[a]
Yield [%]
1
2
3
4
5
6
I
A
A
A
A
B
99
99
OTf
Br
Br
Cl
Cl
70
99[b]
64
B
97[b]
[a]
Procedure A: PdCl2(dppp) (5 mol%), (i-Pr)2NH, toluene,
1108C. Procedure B: Pd(OAc)2 (2 mol%), XPhos
(6 mol%), Et3N, KI (2 mol%) AcOEt, 508C.
With filtration of (i-Pr)2NH2Cl.
[b]
Adv. Synth. Catal. 2015, 357, 1167 – 1174
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
1169

COMMUNICATIONS
HØl›ne D. S. Guerrand et al.
Table 2. Synthesis of boronates from aryl bromides using
BH3·NH(i-Pr)2 as borylating agent.
Scheme 3. Comparison with reactivity with isolated BH2N(i-
Pr)2 on ortho-substituted aryl bromides.
yields, respectively. Nevertheless, the very low reactiv-
ity of electron-poor substrates can be compensated by
addition of potassium iodide. With 0.5 equivalent of
KI, 1-bromo-4-trifluoromethylbenzene led to 99% of
5k and a 68% yield was reached when the aromatic
bears two withdrawing trifluoromethyl substituents
(Table 2, entries 11 and 12). Methyl 4-bromobenzoate
led to the formation of 75% of the desired product
with 25% of methyl benzoate (38% yield after purifi-
cation Table 2, entries 13).
Then, we applied these borylation conditions to
sterically hindered aryl bromides (Scheme 3). Boryla-
tion of ortho-substituted bromides was not strongly
affected by steric hindrance. Indeed 5n, 5o and 5p
were isolated in 99%, 89% and 95% yields, respec-
tively (Scheme 3). This result is in contrast with re-
sults observed with isolated BH2N(i-Pr)2. For instance,
pinacol 2-methylphenylboronate 5o has never been
obtained in yield greater than 50% in the past using
aminoborane. In our case, 5o is isolated in 89% yield.
As a comparison, yields previously obtained with
identical substrates using diisopropylaminoborane as
[17a,22a]
borylation reagent with PdCl2(PPh3)2
or Pd
nanocrystals[29] were significantly lower (Scheme 3).
Aryl chlorides remain challenging substrates and
only few methods are efficient enough to allow their
borylation with limited side product formation, espe-
cially ortho-substituted or electron-poor ones. The
conditions optimized previously (Table 1, entry 6)
proved to be efficient for most aryl chlorides bearing
donor substituents in para- and meta-positions
(Table 3, entries 1 to 3). More importantly, this
method was also applicable to more reluctant aryl
chlorides provided that more potassium iodide was
used. 2-Chlorotoluene and 2-chloroanisole led to the
expected pinacolboronate esters 5o and 5n in 75%
and 99% yields, respectively (Table 3, entries 4 and
[a]
0.5 equiv. of KI were used.
With electron-withdrawing groups, as aforementioned, 5). Aryl chlorides bearing fluorine reacted smoothly
yields decreased sharply. 1-Bromo-4-trifluoromethyl- to give 5q and 5r in excellent yields exceeding 90%
benzene 5k and 1-bromo-3,5-bis(trifluoromethyl)ben- (Table 3, entries 6 and 7) and chlorochromanone was
zene 5l have been synthesized in 65% and 40% converted to 5s without ketone reduction (Table 3,
1170
asc.wiley-vch.de
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2015, 357, 1167 – 1174

COMMUNICATIONS
Amine–Borane Complexes: Air- and Moisture-Stable Partners
Table 3. Synthesis of boronates from aryl chlorides using
BH3·NH(i-Pr)2 as borylating agent.
Scheme 4. Borylation of 2-chlorothiophene on multigram
scale.
sterically hindered and unreactive aryl or heteroaryl
chlorides, known to be very challenging substrates, re-
acted smoothly, and led to borylated products in good
to excellent yields, including on larger scale.
Experimental Section
Techniques
GC-MS analyses were performed with an HP 6890 series
GC-system equipped with a J&W Scientific DB-170 capilla-
ry column, an HP 5973 mass selective detector (EI) using
the following conditions: 708C for 1 min then 208C·minÀ1
1
until 2308C then 6 min at 2308C. H, 11B, 13C and 19F NMR
[a]
2 mol% KI were used.
50 mol% KI were used.
[b]
spectra were recorded on a Bruker 300 MHz Avance I and
a 400 MHz Avance II spectrometer. The chemical shifts (d)
and coupling constants (J) are expressed in ppm and hertz,
respectively. The following abbreviations are used to de-
scribe the multiplicities: s: singlet, d: doublet, t: triplet, dd:
doublet of doublets, td: triplet of doublets, ddd: doublet of
doublets of doublets, m: multiplet.
entry 8). In all cases, the new procedure using directly
diisopropylamine–borane as borylating agent affords
similar or much better yields than previous methods
(Table 3), in particular with deactivated aryl chlorides.
This procedure is not only efficient, but also appli-
cable for the multigram scale preparation of heteroar-
ylboronates. As an example, the borylation of
84 mmol of 2-chlorothiophene led to the isolation of
nearly 15 g of the boron derivative (Scheme 4). This
multigram scale experiment was performed twice to
afford the 1,8-diaminonaphthalene-derived arylborane
6 (Ar-Bdan 6, 73%), used in iterative cross-coupling
reactions,[30] or the aryl pinacolboronate 5f (Ar-Bpin
5f, 81%).
Chemicals
Pinacol and diisopropylamine were purchased from Sigma–
Aldrich and distilled before use. Aryl chlorides, aryl bro-
mides and sodium borohydride were used without further
purification. All catalytic reactions were carried out under
an argon atmosphere unless otherwise specified. All chemi-
cals were stored under argon. Toluene, THF and diethyl
ether were distilled from sodium benzophenone and ethyl
acetate from CaH2. Silica gel (230–400 mesh) purchased
from Merck was used for flash chromatography. Analytical
TLC aluminium plates covered with silica gel 60 F254 were
In summary, we have developed an efficient and
very convenient method for the borylation of aryl and
heteroaryl halides using easily accessible and quite
stable diisopropylamine–borane. It is noteworthy that used.
Adv. Synth. Catal. 2015, 357, 1167 – 1174
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
1171

COMMUNICATIONS
HØl›ne D. S. Guerrand et al.
cooled at À58C, quenched with anhydrous MeOH (2 mL)
and stirred for 1 h at room temperature. All volatiles were
removed under vacuum before adding pinacol (153 mg,
1.3 mmol) and Et2O (2 mL), and the mixture was stirred for
4 h at room temperature. Then the reaction mixture was di-
luted with Et2O (10 mL), and the organic phase was washed
first with a solution of HCl (0.1N, 2”10 mL), followed by
an aqueous solution of CuCl2 (50 gLÀ1, 3”10 mL);[31] it was
then dried over Na2SO4, filtered and concentrated under
vacuum. The crude oil was passed through a pad of silica
gel, eluting with Et2O. The resulting filtrate was concentrat-
ed under vacuum and eventually purified by flash chroma-
tography if some impurities were present in the residue.
Preparation of Amine–Borane Complex 1
To a stirred solution of diisopropylamine (70.6 mL, 0.5 mol)
and NaBH4 (30 g, 0.79 mol) in THF (500 mL) was added at
08C over a period of 45 min sulfuric acid (21.5 mL, 0.6 mol).
The mixture was allowed to warm to room temperature and
stirred for 3 h. The crude mixture was concentrated under
vacuum and the residue was taken up with CH2Cl2, and then
filtered to eliminate all solid residues. The filtrate was
washed with water (4”100 mL). The organic phase was
dried over Na2SO4 and concentrated under reduced pressure
to give the amine–borane complex as colorless oil which sol-
idified upon cooling; yield: 51.8 g (90%).
General Procedure for the Borylation of Aryl
Iodides, Aryl Triflates and Aryl Bromides
Acknowledgements
In a flask A charged with amine–borane complex 1 (0.3 mL,
2 mmol) under an argon atmosphere was added slowly, at
08C, HCl in Et2O (1 mL, 2M solution, 2 mmol). After stir-
ring for 30 min at room temperature distilled (i-Pr)2NH
(0.28 mL, 2 mmol) was added and the solution was stirred
H.D.S.G. acknowledges AST-Innovation for funding.
for 30 min. In a flask B charged with PdCl2dppp (30 mg, References
0.05 mmol) under an argon atmosphere was added, in the
following order: anhydrous toluene (1 mL), distilled (i-
Pr)2NH (0.42 mL, 3 mmol), aryl halide or aryl triflate
(1 mmol) (Procedure A). In the case of aryl bromides bear-
ing electron-withdrawing substituents, potassium iodide
(83 mg, 0.5 mmol) was also introduced in flask B (Procedure
B). Finally, the amine–borane complex obtained in the flask
A in Et2O was filtered and added to flask B. The reaction
mixture was heated at 1108C for 16 h before being cooled at
À58C, quenched with anhydrous MeOH (2 mL) and stirred
for 1 h at room temperature. All volatiles were removed
under vacuum before adding pinacol (153 mg, 1.3 mmol)
and Et2O (2 mL), and the mixture was stirred for 4 h at
room temperature. Then the reaction mixture was diluted
with Et2O (10 mL), and the organic phase was washed first
with a solution of HCl (0.1N, 2”10 mL), followed by an
aqueous solution of CuCl2 (50 gLÀ1, 3”10 mL);[31] it was
then dried over Na2SO4, filtered and concentrated under
vacuum. The crude oil was passed through a pad of silica
gel, eluting with Et2O. The resulting filtrate was concentrat-
ed under vacuum and eventually purified by flash chroma-
tography if some impurities were present in the residue.
[1] D. G. Hall, in: Boronic Acids: Preparation and Applica-
tions in Organic Synthesis and Medicine, (Ed.: D. G.
Hall), Wiley-VCH, Weinheim, 2005, pp 1–99.
[2] a) S. M. Preshlock, B. Ghaffari, P. E. Maligres, S. W.
Krska, R. E. Maleczka, M. R. Smith, J. Am. Chem. Soc.
2013, 135, 7572–7582; b) J. F. Hartwig, Acc. Chem. Res.
2012, 45, 864–873; c) I. A. I. Mkhalid, J. H. Barnard,
T. B. Marder, J. M. Murphy, J. F. Hartwig, Chem. Rev.
2010, 110, 890–931; d) G. A. Chotana, I. I. B. A. Van-
chura, M. K. Tse, R. J. Staples, J. R. E. Maleczka,
I. I. I. M. R. Smith, Chem. Commun. 2009, 5731–5733;
e) N. Miyaura, Bull. Chem. Soc. Jpn. 2008, 81, 1535–
1553; f) T. Ishiyama, N. Miyaura, Chem. Rec. 2004, 3,
271–280.
[3] a) M. Murata, H. Odajima, S. Watanabe, Y. Masuda,
Bull. Chem. Soc. Jpn. 2006, 79, 1980–1982; b) M. K.
Tse, J. Y. Cho, M. R. Smith III, Org. Lett. 2001, 3,
2831–2833; c) S. Shimada, A. S. Batsanov, J. A. K.
Howard, T. B. Marder, Angew. Chem. 2001, 113, 2226–
2229; Angew. Chem. Int. Ed. 2001, 40, 2168–2171; d) H.
Chen, S. Schlecht, T. C. Semple, J. F. Hartwig, Science
2000, 287, 1995–1997.
[4] a) T. Ishiyama, N. Miyaura, Pure Appl. Chem. 2006, 78,
1369–1375; b) T. Ishiyama, Y. Nobuta, J. F. Hartwig, N.
Miyaura, Chem. Commun. 2003, 9, 2924–2925; c) J.-Y.
Cho, M. K. Tse, D. Holmes, R. E. Maleczka Jr, M. R.
Smith III, Science 2002, 295, 305–308; d) T. Ishiyama, J.
Takagi, K. Ishida, N. Miyaura, N. R. Anastasi, J. F.
Hartwig, J. Am. Chem. Soc. 2002, 124, 390–391; e) T.
Ishiyama, J. Takagi, J. F. Hartwig, N. Miyaura, Angew.
Chem. 2002, 114, 3182–3184; Angew. Chem. Int. Ed.
2002, 41, 3056–3058.
[5] a) J. M. Murphy, X. Liao, J. F. Hartwig, J. Am. Chem.
Soc. 2007, 129, 15434–15435; b) J. Y. Cho, C. N. Iverson,
M. R. Smith III, J. Am. Chem. Soc. 2000, 122, 12868–
12869; c) G. A. Chotana, M. A. Rak, M. R. Smith, J.
Am. Chem. Soc. 2005, 127, 10539–10544; d) K. M.
Crawford, T. R. Ramseyer, C. J. A. Daley, T. B. Clark,
Angew. Chem. Int. Ed. 2014, 53, 7589–7593; e) I.
General Procedure for the Borylation of Aryl
Chlorides
In a flask A charged with amine–borane complex 1 (0.3 mL,
2 mmol) under an argon atmosphere was added slowly at
08C, HCl in AcOEt (1 mL, 2M solution, 2 mmol). After stir-
ring for 30 min at room temperature distilled (i-Pr)2NH
(0.28 mL, 2 mmol) was added and the solution was stirred
for 30 min. In a flask B charged with Pd(OAc)2 (4.5 mg,
0.02 mmol), potassium iodide (3.3 mg, 0.02 mmol if proce-
dure C is followed or 83 mg, 0.5 mmol in case of procedure
D) and XPhos (28 mg, 0.06 mmol) under an argon atmos-
phere were added, in the following order: anhydrous EtOAc
(1 mL), distilled Et3N (0.4 mL, 3 mmol), and aryl chloride
(1 mmol). Finally, the amine–borane complex obtained in
the flask A in EtOAc was filtered and added to flask B. The
reaction mixture was heated at 508C for 16 h before being
1172
asc.wiley-vch.de
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2015, 357, 1167 – 1174

COMMUNICATIONS
Amine–Borane Complexes: Air- and Moisture-Stable Partners
Sasaki, T. Amou, H. Ito, T. Ishiyama, Org. Biomol.
Chem. 2014, 12, 2041–2044; f) A. Ros, B. Estepa, R.
López-Rodríguez, E. lvarez, R. Fernµndez, J. M. Las-
saletta, Angew. Chem. 2011, 123, 11928–11932; Angew.
Chem. Int. Ed. 2011, 50, 11724–11728; g) H. Itoh, T. Ki-
kuchi, T. Ishiyama, N. Miyaura, Chem. Lett. 2011, 40,
1007–1008; h) P. C. Roosen, V. A. Kallepalli, B. Chatto-
padhyay, D. A. Singleton, R. E. Maleczka, M. R. Smith,
J. Am. Chem. Soc. 2012, 134, 11350–11353; i) T. Ishiya-
ma, H. Isou, T. Kikuchi, N. Miyaura, Chem. Commun.
2010, 46, 159–161; j) J. F. Hartwig, Chem. Soc. Rev.
2011, 40, 1992–2002.
A. M. Resmerita, C. Liu, B. M. Rosen, V. Percec, J.
Org. Chem. 2010, 75, 5438–5452; e) P. Leowanawat,
A. M. Resmerita, C. Moldoveanu, C. Liu, N. Zhang,
D. A. Wilson, L. M. Hoang, B. M. Rosen, V. Percec, J.
Org. Chem. 2010, 75, 7822–7828; f) M. Murata, T. Sam-
bommatsu, T. Oda, S. Watanabe, Y. Masuda, Heterocy-
cles 2010, 80, 213–218; g) D. A. Wilson, C. J. Wilson, C.
Moldoveanu, A. M. Resmerita, P. Corcoran, L. M.
Hoang, B. M. Rosen, V. Percec, J. Am. Chem. Soc.
2010, 132, 1800–1801; h) C. Moldoveanu, D. A. Wilson,
C. J. Wilson, P. Corcoran, B. M. Rosen, V. Percec, Org.
Lett. 2009, 11, 4974–4977; i) D. A. Wilson, C. J. Wilson,
B. M. Rosen, V. Percec, Org. Lett. 2008, 10, 4879–4882;
j) B. M. Rosen, C. Huang, V. Percec, Org. Lett. 2008,
10, 2597–2600; k) A. B. Morgan, J. L. Jurs, J. M. Tour, J.
Appl. Polym. Sci. 2000, 76, 1257–1268.
[6] a) J. Ratniyom, N. Dechnarong, S. Yotphan, S. Kiatise-
vi, Eur. J. Org. Chem. 2014, 1381–1385; b) C. S. Bello, J.
Schmidt-Leithoff, Tetrahedron Lett. 2012, 53, 6230–
6235; c) G. A. Molander, S. L. J. Trice, S. M. Kennedy,
S. D. Dreher, M. T. Tudge, J. Am. Chem. Soc. 2012, 134,
11667–11673; d) L. Wang, X. Cui, J. Li, Y. Wu, Z. Zhu,
Y. Wu, Eur. J. Org. Chem. 2012, 2012, 595–603;
e) W. K. Chow, O. Y. Yuen, C. M. So, W. T. Wong, F. Y.
Kwong, J. Org. Chem. 2012, 77, 3543–3548; f) G. A.
Molander, S. L. J. Trice, S. M. Kennedy, J. Org. Chem.
2012, 77, 8678–8688; g) G. A. Molander, S. L. J. Trice,
S. M. Kennedy, Org. Lett. 2012, 14, 4814–4817; h) J. Lu,
Z. Z. Guan, J. W. Gao, Z. H. Zhang, Appl. Organomet.
Chem. 2011, 25, 537–541; i) S. Kawamorita, H. Ohmiya,
T. Iwai, M. Sawamura, Angew. Chem. 2011, 123, 8513–
8516; Angew. Chem. Int. Ed. 2011, 50, 8363–8366; j) W.
Tang, S. Keshipeddy, Y. Zhang, X. Wei, J. Savoie, N. D.
Patel, N. K. Yee, C. H. Senanayake, Org. Lett. 2011, 13,
1366–1369; k) W. K. Chow, C. M. So, C. P. Lau, F. Y.
Kwong, Chem. Eur. J. 2011, 17, 6913–6917; l) M.
Murata, T. Oda, Y. Sogabe, H. Tone, T. Namikoshi, S.
Watanabe, Chem. Lett. 2011, 40, 962–963; m) N. Pra-
veenganesh, E. Demory, C. Gamon, V. Blandin, P. Y.
Chavant, Synlett 2010, 2403–2406; n) L. Wang, J. Li, X.
Cui, Y. Wu, Z. Zhu, Adv. Synth. Catal. 2010, 352, 2002–
2010; o) K. L. Billingsley, S. L. Buchwald, J. Org.
Chem. 2008, 73, 5589–5591; p) M. Murata, T. Oda, S.
Watanabe, Y. Masuda, Synthesis 2007, 351–354; q) M.
Murata, T. Sambommatsu, S. Watanabe, Y. Masuda,
Synlett 2006, 1867–1870; r) H. Fang, G. Kaur, J. Yan, B.
Wang, Tetrahedron Lett. 2005, 46, 1671–1674; s) P. E.
[8] a) F. Labre, Y. Gimbert, P. Bannwarth, S. Olivero, E.
DuÇach, P. Y. Chavant, Org. Lett. 2014, 16, 2366–2369;
b) C. Kleeberg, L. Dang, Z. Lin, T. B. Marder, Angew.
Chem. 2009, 121, 5454–5458; Angew. Chem. Int. Ed.
2009, 48, 5350–5354; c) W. Zhu, D. Ma, Org. Lett. 2006,
8, 261–263.
[9] Y. Nagashima, R. Takita, K. Yoshida, K. Hirano, M.
Uchiyama, J. Am. Chem. Soc. 2013, 135, 18730–18733.
[10] W. K. Chow, O. Y. Yuen, P. Y. Choy, C. M. So, C. P.
Lau, W. T. Wong, F. Y. Kwong, RSC Adv. 2013, 3,
12518–12539.
[11] a) P. Li, C. Fu, S. Ma, Org. Biomol. Chem. 2014, 12,
3604–3610; b) G. A. Molander, S. L. J. Trice, S. D.
Dreher, J. Am. Chem. Soc. 2010, 132, 17701–17703;
c) C. Xu, J. F. Gong, M. P. Song, Y. J. Wu, Transition
Met. Chem. 2009, 34, 175–179; d) K. L. Billingsley, T. E.
Barder, S. L. Buchwald, Angew. Chem. 2007, 119, 5455–
5459; Angew. Chem. Int. Ed. 2007, 46, 5359–5363; e) A.
Fürstner, G. Seidel, Org. Lett. 2002, 4, 541–543.
[12] a) M. Tobisu, H. Kinuta, Y. Kita, E. RØmond, N. Chata-
ni, J. Am. Chem. Soc. 2012, 134, 115–118; b) H. Kinuta,
Y. Kita, E. RØmond, M. Tobisu, N. Chatani, Synthesis
2012, 44, 2999–3002.
[13] a) M. Tobisu, K. Nakamura, N. Chatani, J. Am. Chem.
Soc. 2014, 136, 5587–5590; b) K. Huang, D. G. Yu, S. F.
Zheng, Z. H. Wu, Z. J. Shi, Chem. Eur. J. 2011, 17, 786–
791.
[14] J. Zhang, H. H. Wu, Eur. J. Org. Chem. 2013, 6263–
6266.
[15] a) D. Qiu, L. Jin, Z. Zheng, H. Meng, F. Mo, X. Wang,
Y. Zhang, J. Wang, J. Org. Chem. 2013, 78, 1923–1933;
b) F. Mo, Y. Jiang, D. Qiu, Y. Zhang, J. Wang, Angew.
Chem. 2010, 122, 1890–1893; Angew. Chem. Int. Ed.
2010, 49, 1846–1849.
[16] a) E. Yamamoto, K. Izumi, Y. Horita, S. Ukigai, H. Ito,
Top. Catal. 2014, 57, 940–945; b) E. Yamamoto, K.
Izumi, Y. Horita, H. Ito, J. Am. Chem. Soc. 2012, 134,
19997–20000.
ˇ
ˇ
Broutin, I. Cerna, M. Campaniello, F. Leroux, F. Colo-
bert, Org. Lett. 2004, 6, 4419–4422; t) O. Baudoin, M.
Cesario, D. GuØnard, F. GuØritte, J. Org. Chem. 2002,
67, 1199–1207; u) T. Ishiyama, K. Ishida, N. Miyaura,
Tetrahedron 2001, 57, 9813–9816; v) O. Baudoin, D.
GuØnard, F. GuØritte, J. Org. Chem. 2000, 65, 9268–
9271; w) M. Murata, T. Oyama, S. Watanabe, Y.
Masuda, J. Org. Chem. 2000, 65, 164–168; x) M.
Murata, S. Watanabe, Y. Masuda, J. Org. Chem. 1997,
62, 6458–6459; y) T. Ishiyama, Y. Itoh, T. Kitano, N.
Miyaura, Tetrahedron Lett. 1997, 38, 3447–3450; z) T.
Ishiyama, M. Murata, N. Miyaura, J. Org. Chem. 1995,
60, 7508–7510.
[17] a) L. Euzenat, D. Horhant, Y. Ribourdouille, C.
Duriez, G. Alcaraz, M. Vaultier, Chem. Commun. 2003,
2280–2281; b) M. Vaultier, G. Alcaraz, C. Duriez, L.
Euzenat, Y. Ribourdouille, WO Patent WO03053981;
c) L. EuzØnat, D. Horhant, C. Brielles, G. Alcaraz, M.
Vaultier, J. Organomet. Chem. 2005, 690, 2721–2724.
[18] L. Marciasini, N. Richy, M. Vaultier, M. Pucheault,
Chem. Commun. 2012, 48, 1553–1555.
[7] a) G. A. Molander, L. N. Cavalcanti, C. García-García,
J. Org. Chem. 2013, 78, 6427–6439; b) Y. Sogabe, T. Na-
mikoshi, S. Watanabe, M. Murata, Synthesis 2012, 44,
1233–1236; c) T. Yamamoto, T. Morita, J. Takagi, T. Ya-
makawa, Org. Lett. 2011, 13, 5766–5769; d) C. Moldo-
veanu, D. A. Wilson, C. J. Wilson, P. Leowanawat,
Adv. Synth. Catal. 2015, 357, 1167 – 1174
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
1173

COMMUNICATIONS
HØl›ne D. S. Guerrand et al.
[19] a) H. D. S. Guerrand, L. D. Marciasini, M. Jousseaume,
M. Vaultier, M. Pucheault, Chem. Eur. J. 2014, 20,
5573–5579; b) M. Pucheault, H. Guerrand, L. Marciasi-
ni, M. Vaultier, (CNRS, UB1, IPB), European Patent
EP 13306667.0, 2013.
[20] a) L. D. Marciasini, M. Vaultier, M. Pucheault, Tetrahe-
dron Lett. 2014, 55, 1702–1705; b) M. Pucheault, L.
Marciasini, M. Vaultier, WO Patent WO2014009169,
2014; c) L. D. Marciasini, N. Richy, M. Vaultier, M. Pu-
cheault, Adv. Synth. Catal. 2013, 355, 1083–1088.
[21] J. L. Wood, L. Marciasini, M. Vaultier, M. Pucheault,
Synlett 2014, 25, 551–555.
[22] a) D. Haddenham, C. L. Bailey, C. Vu, G. Nepomuceno,
S. Eagon, L. Pasumansky, B. Singaram, Tetrahedron
2011, 67, 576–583; b) L. Pasumansky, D. Haddenham,
J. W. Clary, G. B. Fisher, C. T. Goralski, B. Singaram, J.
Org. Chem. 2008, 73, 1898–1905.
[23] a) J. R. Vance, A. P. M. Robertson, K. Lee, I. Manners,
Chem. Eur. J. 2011, 17, 4099–4103; b) M. S. Hill, M.
Hodgson, D. J. Liptrot, M. F. Mahon, Dalton Trans.
2011, 40, 7783–7790; c) M. E. Sloan, A. Staubitz, T. J.
Clark, C. A. Russell, G. C. Lloyd-Jones, I. Manners, J.
Am. Chem. Soc. 2010, 132, 3831–3841; d) T. J. Clark, I.
Manners, J. Organomet. Chem. 2007, 692, 2849–2853;
e) T. J. Clark, C. A. Russell, I. Manners, J. Am. Chem.
Soc. 2006, 128, 9582–9583; f) C. A. Jaska, K. Temple,
A. J. Lough, I. Manners, J. Am. Chem. Soc. 2003, 125,
9424–9434.
[24] H. D. S. Guerrand, L. D. Marciasini, T. Gendrineau, O.
Pascu, S. Marre, S. Pinet, M. Vaultier, C. Aymonier, M.
Pucheault, Tetrahedron 2014, 70, 6156–6161.
[25] Commercially available, CAS# 55124-35-1.
[26] a) F. H. Stephens, R. T. Baker, U.S. Patent 7,645,902
B2, 2010; b) F. H. Stephens, R. T. Baker, M. H. Matus,
D. J. Grant, D. A. Dixon, Angew. Chem. 2007, 119,
760–763; Angew. Chem. Int. Ed. 2007, 46, 746–749;
c) F. Stephens, R. Baker, U.S. Patent 0292068A1, 2006.
[27] H. K. Lingam, C. Wang, J. C. Gallucci, X. Chen, S. G.
Shore, Inorg. Chem. 2012, 51, 13430–13436.
[28] O. J. Metters, A. M. Chapman, A. P. M. Robertson,
C. H. Woodall, P. J. Gates, D. F. Wass, I. Manners,
Chem. Commun. 2014, 50, 12146–12149.
[29] a) O. Pascu, L. Marciasini, S. Marre, M. Vaultier, M.
Pucheault, C. Aymonier, Nanoscale 2013, 5, 12425–
12431; b) T. Gendrineau, S. Marre, M. Vaultier, M. Pu-
cheault, C. Aymonier, Angew. Chem. 2012, 124, 8653–
8656; Angew. Chem. Int. Ed. 2012, 51, 8525–8528.
[30] a) H. Noguchi, K. Hojo, M. Suginome, J. Am. Chem.
Soc. 2007, 129, 758–759; b) H. Noguchi, T. Shioda, C.-
M. Chou, M. Suginome, Org. Lett. 2008, 10, 377–380.
[31] CuCl2 was found to help in elimination of the slight
excess of pinacol added during work-up. CuCl2 has
been found to be the best salt among MgCl2, CaCl2,
CuCl, CuBr, CuBr2, CuSO4, ZnCl2 and FeCl3.
1174
asc.wiley-vch.de
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2015, 357, 1167 – 1174