Palladium-Catalysed Carboborylation for the Synthesis of Borylated Indanes

Article abstract of DOI:10.1002/ejoc.202100309

A palladium-catalysed carboborylation reaction for the synthesis of borylated indanes has been investigated. This reaction proceeds in good yields with an achiral catalyst, and is tolerant of substitution on the aryl ring, although sensitivity to the subs

Full text of DOI:10.1002/ejoc.202100309

European Journal of Organic Chemistry
Accepted Article
Accepted Article
Title: Palladium-catalysed carboborylation for the synthesis of
borylated indanes
Authors: Andrzej Zieba and Joel Francis Hooper
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.202100309
Link to VoR: https://doi.org/10.1002/ejoc.202100309
0
1/2020

European Journal of Organic Chemistry
10.1002/ejoc.202100309
COMMUNICATION
DOI: 10.1002/adsc.202((will be filled in by the editorial staff))
Palladium-catalysed carboborylation for the synthesis of
borylated indanes
a
a
Andrzej Zieba and Joel F. Hooper *
a
School of Chemistry, Monash University, Clayton 3800, Victoria, Australia
*
joel.hooper@monash.edu
Received: ((will be filled in by the editorial staff))
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######.((Please
delete if not appropriate))
Abstract. A palladium catalysed carboborylation reaction employed hydride as a nucleophile in a Pd-catalysed
6
for the synthesis of borylated indanes has been investigated. reductive cyclisation reaction. This chemistry has
This reaction proceeds in good yields with an achiral since proven to be quite robust and tolerable of many
7
8
catalyst, and is tolerant of substitution on the aryl ring, cross coupling partners including cyanide, iodine as
9
10
although sensitivity to the substitution of the alkene was well as boronates and carbon-based nucleophiles
observed. Initial studies towards an enantioselective version
of this reactions were undertaken, identifying
phosphoramidites as a promising ligand class. This allowed
for the synthesis of chiral indane and indolone products with
moderate levels of enantioselectivity.
(
Figure 1b).
Despite such progress, the majority of
enantioselective palladium-catalysed anion capture
cascades have utilised hydride reduction,
functionalisation of heteroarenes, Heck coupling,
Suzuki-type coupling or Sonagashira coupling in the
final step. A number of dearomative Heck-type
couplings have been reported, including Lautens’
4, 11
C-H
12
13
14
Keywords: Borylation, cascade cyclisation, palladium
catalysis, anion capture
15
enantioselective
dearomatization/borylation
of
1
5c
indoles,
highlighting the potential of borylation
The rapid and efficient generation of molecular
complexity is a major goal of organic chemistry and
catalysis. To this end, identifying processes which
allow for the formation of new carbon-carbon bonds
while also controlling the formation of stereochemistry
is highly desirable. One fundamental process that
meets this need is the catalytic carbopalladation of
reactions in enantioselective anion capture cascades.
a) Pd catalysed anion capture cascades
R
R
[
Pd],
Ligand,
X
Y
R
[Pd]
Nu
Nu
Y
Y
1
b) Previous Work
alkenes. This process forms a new C-C bond,
H3C
R
R
X
R
generates up to two new stereocentres and generates a
H
CN
I
BPin
new σ-alkyl-palladium complex in one step.
O
O
n
2
N
H
N
N
In the Mizoroki-Heck reaction, the prototypical
Pg
Pg
example
of
catalytic carbopalladation,
the
Larock (1987)
R
Zhu (2007)
Lautens (2011)
Vachhani (2015)
stereochemical information formed during this step is
subsequently lost through a -hydride elimination
process. Thus, a number of groups have looked at
strategies to intercept the σ-alkyl-palladium complex
formed by alkene carbopalladation with nucleophiles,
allowing for the difunctionalisation of alkenes and the
formation of new stereocentres. These processes have
R
R
H
alkyl/aryl/
alkynyl or
alkenyl
R
O
n
X
X
O
Diaz (1998), Jia (2015),
Zhu (2017), Zhang (2018)
Zhu (2015), Zhang (2019)
Kong (2019), Zhang (2020)
Kong, (2019)
O
BPin
R
X
3
been termed “anion capture cascades” (Figure 1a).
In these cascade processes, -hydride elimination
can be avoided by utilising 1,1-disubstituded alkenes,
which lack a hydrogen at the -position following
carbopalladation. Alternatively, -hydride elimination
can be suppressed through stereoelectronic control of
R
N
Pg
R
Zhao (2015)
c) This Work
Lautens (2019)
Hong and Jia (2020)
R
R
Pd(OAc)2,
PPh3,
OTf
Pd (dba) ,
BPin
BPin
2
3
4
5
L*
the reactive intermediates or through ligand control.
R
B2Pin2
B2Pin2
The σ-alkyl-palladium complex is a versatile
intermediate for palladium catalysed cascade reactions.
The σ-alkyl-palladium complex was utilised
successfully in the seminal work by Larock, who
Figure 1. Pd catalysed anion capture cascades
1
This article is protected by copyright. All rights reserved.

European Journal of Organic Chemistry
10.1002/ejoc.202100309
Alkyl organoboronates are valuable compounds in bulkier iPr group (2d) gave a considerably reduced
organic chemistry, due to their flexible use in cross- yield of 35%. Substitution of the aryl ring with both
coupling
chemistry
The
and
functional
practical use
group electron-withdrawing (2e,f,i) and electron-donating
of groups (2g,h) was well tolerated under these
interconversion.16
organoboronates has increased with advancements in conditions.
1
7
Pd and Pt catalysis, with di-borylation, silyl-
1
8
borylation and carbo-borylation methods becoming
1
9
available. The synthetic advantages of boronates
includes their stability to air and moisture as well as the
vast array of transformations which enable their use as
synthons in the synthesis of drugs and natural products.
In 2015, Vachhani and Van der Eycken demonstrated
9
a borylative cascade cyclisation to form oxindoles. To
our knowledge, the only enantioselective carbo-
borylation reactions of intercepted σ-alkyl-palladium
complexes have been reported by Tong for the
2
0
synthesis of 3,3-disubstituted tetrahydropyridines
and Lautens for the dearomative cyclisation of
1
5c
indoles. Herein, we report a palladium catalysed
carboborylation reaction for the synthesis of borylated
indanes, providing rapid access to these valuable
synthons (Figure 1, c).
Scheme 1. Examples of alkene carboborylation
We began our study by examining the cascade
cyclisation/borylation of aryl bromide 1a. We were
We next investigated the cascade cyclisation/
borylation of substrates with an aryl-substituted alkene
initially pleased to see that treatment of 1a with PdCl
2
(
10 mol%) in the presence of B
2
Pin and KOAc in
2
(
Scheme 2). Unfortunately, when the aryltriflate 4 was
dioxane at 80 °C provided a 25% yield of the desired
subjected to the standard conditions the cyclised
product 5 was not observed; only the direct borylation
product 6 was isolated in 36% yield. In addition, the
trisubstituted alkene substrate 7 also delivered the
direct borylation product 9, rather than the indane 8.
The use of an alternative borylating agent was
attempted, using bis(neopentyl glycolato)diboron with
the standard substrate 1b. Under these conditions, the
cyclised product 8 was not observed, with the
arylboronate 9 isolated in 17% yield.
cyclised product 2a (Table 1; Entry 1).
While the use of a bis-phosphine ligand with PdCl
2
or Pd
and 3) the combination of dppf or PPh
gave the desired product in good yields (Entries 4 and
). Given the ready availability of PPh we chose to
2
(dba)
3
gave no improvement in yield (Entries 2
3
and Pd(OAc)
2
5
3
proceed with this ligand for further studies. The
reaction was also found to proceed just as well when
the aryl triflate 1b was used (Entry 6). Further studies
were conducted with this psuedohalide due to easy
access to the starting materials.
Ph
BPin
standard
conditions
OTf
BPin
Table 1. Optimisation of the carboborylation of 1.
Ph
Ph
4
5, <5%
6, 36%
H3C
Ph
OTf
BPin
standard
conditions
BPin
Ph
Ph
Entry Pd sourcea
Substrate Liganda Yieldd
7
CH3
8, <5%
9, 70%
CH3
1
2
3
4
5
6
PdCl
PdCl
2
2
1a
1a
1a
1a
1a
1b
-
25%
18%
<5%
77%
74%
74%
dppf
dppf
dppf
PPh
PPh
10 mol% Pd(OAc)2,
20 mol% PPh3,
B2Neo2 (1.1 equiv.),
b
H C
BNeo
Pd
2
(dba)
3
3
BNeo
Pd(OAc)
Pd(OAc)
2
CH3
1b
c
c
KOAc (3 equiv.),
dioxane, 80°C, 18 h
2
3
10, <5%
11, 17%
Pd(OAc)
2
3
a10 mol%. 5 mol%. 20 mol%. Isolated yield.
b
c
d
Scheme 2. Attempted carboborylation of aryl alkenes
With optimised conditions in hand, we investigated
the scope of this reaction by varying the substituents at Studies into the enantioselective synthesis of 3,3-
the aryl and olefinic positions. The reaction was found
to be tolerant to substitution of the olefin methyl group
for ethyl and butyl groups (Scheme 1, 2b,c) while the
disubstituted indanes by carboborylation were
also conducted. (See SI for full optimisation
table.) Initially, the bromide 1a was treated with
2
This article is protected by copyright. All rights reserved.

European Journal of Organic Chemistry
10.1002/ejoc.202100309
substituted 12b gave comparable yields to the parent
Pd(OAc)
2
, (R)-BINAP (A), B
2
Pin and KOAc in
2
reaction (58%, 82:18 e.r), the electron-donating p-CH
3
dioxane. This provided the product 12a in low
yield and poor enantioselectivity (Table 2, Entry
substrate 12c performed much worse (35%, 81:19 e.r)
and p-OCH (12d) did not react at all. The Et
substituted alkene substrate 12e gave a comparable
in no reaction, while the monodentate ligands (R)- yield and enantioselectivity (55%, 78:22 e.r), while the
3
1
). The use of (S)-tBu-PHOX ligand (B) resulted
iPr substituted gave reduced yield of 21% (12g). The
naphthyl substrate 12f and the trisubstituted olefin 12h
resulted in no reaction. Finally, enantioselective
carbo-borylation was attempted for the synthesis of
chiral oxindoles. Although oxindoles 12f and 12g were
SITCP (C) and (R)-SIPHOS (D) gave the indane
1
2a with negligible enantioselectivity (Entries 2-
4
). The addition of silver salts to this reaction was
attempted, as formation of the cationic palladium
intermediate has been associated with higher synthesised successfully under the conditions, the
2
1
enantioselectivities of the products were reduced
slightly when compared to the parent reaction.
enantioselectivity in Heck reactions (Entry 5).
This resulted in reduced yield and poor
enantioselectivity. Switching the substrate to
1
2
0 mol% Pd(OAc)2,
0 mol% F,
H3C
triflate 1b gave
a
modest increase in
OTf
BPin
B2Pin2 (1.1 equiv.),
enantioselectivity (Entry 6), which could be
further increased through the use of the
CH3
KOAc (3 equiv.),
dioxane, 80°C, 18-48 h
12a, 74%,
1
b
80:20 e.r
phosphoramidite
(R,S,S)-PE-Monophos,
H3C
H3C
H3C
providing indane 12a in 58% yield and 80:20 e.r.
BPin
BPin
BPin
Table 2. Optimisation of enantioselective carboborylation.
F
H3C
H3CO
12b, 57%
12c, 35%
12d
82:18 e.r
81:19 e.r
no reaction
X
Pd source (10 mol%),
ligand (20 mol%),
B2Pin2 (1.1 equiv.),
H3C
CH3
H3C
BPin
H3C
CH3
Et
BPin
BPin
BPin
KOAc (3 equiv.),
dioxane, 80°C, 18 h
1
a, X = Br
12a
1b, X = OTf
12e, 55%
12g, 21%
12f
78:22 e.r
62:38 e.r
no reaction
O
CH3
H C
3
H C
PPh2
PPh2
O
O
Ph
3
PPh
P
N
H3C
BPin
BPin
PPh2
N
CH3
BPin
O
O
tBu
N
N
B
CH3
Bn
A
C
D
1
2h
12i, 48%
12j, 39%
28:72 e.r
no reaction
26:74 e.r
Ph
N
Ph
N
O
O
CH3
CH3
O
O
CH3
CH3
P
P
Scheme 3. Examples of enantioselective carboborylation
Ph
Ph
E
F
The absolute configuration of the major enantiomer
of compounds 12a-j was assigned by oxidation of the
borylated oxindole 12i to the known alcohol (R)-13
Substrate Ligand Yield (e.r)b
a
Entry Pd source
1
2
3
4
5
6
7
8
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
1a
1a
1a
1a
1a
1b
1b
1b
A
B
C
D
D
D
E
F
32%(52:48)
N/R
(
Scheme 4). Comparison of the optical rotation of (R)-
3 ([α] = -4.0, lit [α] = -8.5, >99:1 e.r) and the chiral
2
2
2
2
2
1
D
D
68%(45:55)
69%(45:55)
49%(54:46)
62%(70:30)
53%(66:34)
58%(80:20)
22
HPLC data (see SI) with the reported values
confirmed the (R)- configuration of this product. The
alcohol (R)-13 has been previously reported as an
c
intermediate in the synthesis of natural products (-)-
esermethole and (-)-phytostigmine,
potential new route to this class of alkaloids.
d
d
Pd
Pd
2
(dba)
(dba)
3
23
offering a
2
3
a
b
Isolated yield. e.r determined by chiral HPCL; N/R = no
reaction. 1 equiv. of Ag CO added 5 mol% cat. loading.
2 3
c
d
Having determined reasonable reaction conditions
for the enantioselective carbo-borylation reaction, a
small scope was investigated (Scheme 3). With these
enantioselective conditions, the reaction was found to
be much more sensitive to the electronic nature of the
aryl group. Whilst the electron-withdrawing p-F
3
This article is protected by copyright. All rights reserved.

European Journal of Organic Chemistry
10.1002/ejoc.202100309
1
2
3
. a) Y. Ping, Y. Li, J. Zhu, W. Kong, Angew. Chem., Int.
Ed., 2019, 58, 1562-1573; b) D. B. Werz, Targets
Heterocycl. Syst., 2016, 20, 393-408.
. a) R. F. Heck, J. P. Nolley, Jr., J. Org. Chem., 1972, 37,
2
320-2322; b) T. Mizoroki, K. Mori, A. Ozaki, Bull.
Chem. Soc. Jap., 1971, 44, 581.
. a) R. Grigg, V. Sridharan, Tetrahedron Lett., 1993, 34,
7
471-7474; b) R. Grigg, V. Sridharan, J. Organomet.
Chem., 1999, 576, 65-87.
4
5
. A. Minatti, X. Zheng, S. L. Buchwald, J. Org. Chem.,
2
007, 72, 9253-9258.
. a) C. Skoeld, J. Kleimark, A. Trejos, L. R. Odell, S. O.
Nilsson Lill, P.-O. Norrby, M. Larhed, Chem. - Eur. J.,
Scheme 4. Oxidation and assignment of configuration
2
012, 18, 4714-4722,; b) C.-W. Lee, K. S. Oh, K. S. Kim,
K. H. Ahn, Org. Lett., 2000, 2, 1213-1216; c) Z. Huo, N.
T. Patil, T. Jin, N. K. Pahadi, Y. Yamamoto, Adv. Synth.
Catal., 2007, 349, 680-684.
In summary, we have reported the intramolecular
Pd-catalysed carboborylation cascade for the synthesis
of 3,3-disubstituted indanes using B
2
Pin . It was
2
observed that the reaction was tolerant of variable
electronics at the aryl substituent and sensitive to
6
7
8
9
. R. C. Larock, S. Babu, Tetrahedron Lett., 1987, 28,
5
291-5294.
substitution around the olefin. When the B
2
Neo dimer
2
. A. Pinto, Y. Jia, L. Neuville, J. Zhu, Chem. - Eur. J.,
was used, selectivity towards the non-cyclised Miyaura
borylation product was observed. Finally, the first
enantioselective Pd-catalysed carboborylation for the
synthesis of chiral indanes has been successfully
reported in moderate yields and enantioselectivity.
2
007, 13, 961-967.
. S. G. Newman, M. Lautens, J. Am. Chem. Soc., 2011,
1
33, 1778-1780.
. D. D. Vachhani, H. H. Butani, N. Sharma, U. C. Bhoya,
A. K. Shah, E. V. Van der Eycken, Chem. Commun.,
2
015, 51, 14862-14865.
Experimental Section
1
0. a) B. Burns, R. Grigg, P. Ratananukul, V. Sridharan, P.
Stevenson, S. Sukirthalingam, T. Worakun, Tetrahedron
Lett., 1988, 29, 5565-5568; b) B. Burns, R. Grigg, V.
Santhakumar, V. Sridharan, P. Stevenson, T. Worakun,
Tetrahedron, 1992, 48, 7297-7320; c) B. Burns, R. Grigg,
V. Sridharan, P. Stevenson, S. Sukirthalingam, T.
Worakun, Tetrahedron Lett., 1989, 30, 1135-1138; d) P.
Fretwell, R. Grigg, J. M. Sansano, V. Sridharan, S.
Sukirthalingam, D. Wilson, J. Redpath, Tetrahedron,
Experimental
procedure
for
enantioselective
(dba) (7.2 mg
carboborylation of 1b.
To a dry round-bottom flask was added Pd
2
3
0
.05 equiv.) and (R,S,S)-PE-Monophos (17 mg, 0.2 equiv.)
and the flask purged with N
2
gas for 10 minutes. The
contents of the flask were dissolved in 1 mL dry and
degassed dioxane and allowed to stir for 30 min until the
solution turned from purple to yellow. The solution was
transferred to a pre-purged 10 mL reaction vial containing
2 2
B Pin (46 mg, 1.1 equiv.) and dry KOAc (47 mg, 3 equiv.).
2
000, 56, 7525-7539; e) R. Grigg, J. M. Sandano, V.
Aryltriflate 1b (39 µL, 0.16 mmol) was then added to the
reaction mixture via micro syringe and the reaction was
warmed to 80°C for 16 hours. The reaction was then cooled,
diluted with EtOAc and filtered. The extract was
concentrated and purified via flash column chromatography
Santhakumar, V. Sridharan, R. Thangavelanthum, M.
Thornton-Pett, D. Wilson, Tetrahedron, 1997, 53,
1
Sukirthalingam, T. Worakun, Tetrahedron Lett., 1989,
30, 1139-1142.
1803-11826; f) R. Grigg, V. Sridharan, S.
(
40% CH
2 2
Cl /hexanes) to give the product (25 mg, 74%
yield) as a clear oil.
1
1. a) P. Diaz, F. Gendre, L. Stella, B. Charpentier,
Tetrahedron, 1998, 54, 4579-4590; b) W. Kong, Q.
Wang, J. Zhu, Angew. Chem., Int. Ed., 2017, 56, 3987-
R
f
= 0.17 (20% CH
2 2
Cl /hexanes); IR υmax (neat) 3070, 2977,
2
8
7
1
933, 2866, 1477, 1449, 1354, 1318, 1269, 1213, 1142, 968,
1
3
80, 847, 756, 727; H NMR (400 MHz, CDCl ): δ 7.19-
.09 (m, 4H), 2.93-2.84 (m, 2H), 2.12 (ddd, J = 7, 8, 12.5 Hz,
H), 1.94 (ddd, J = 6, 8, 12.5 Hz, 1H), 1.31 (s, 3H), 1.26 (d,
3
991; c) Z.-M. Zhang, B. Xu, Y. Qian, L. Wu, Y. Wu, L.
Zhou, Y. Liu, J. Zhang, Angew. Chem., Int. Ed., 2018,
57, 10373-10377; d) C. Shen, R.-R. Liu, R.-J. Fan, Y.-L.
Li, T.-F. Xu, J.-R. Gao, Y.-X. Jia, J. Am. Chem. Soc.,
J = 15 Hz, 1H), 1.20 (d, J = 7 Hz, 12H), 1.12 (d, J = 15 Hz,
13
1
1
H); C NMR (100 MHz, CDCl
31.1, 129.3, 125.2, 109.9, 83.5, 41.8, 35.0, 25.0, 22.6.
3
): δ 149.6, 146.4, 136.3,
2
015, 137, 4936-4939; e) G. Yue, K. Lei, H. Hirao, J.
Chiral HPLC was performed on a Chiralpak AD-H column,
eluted in 99.5:0.5 hexane:iPrOH at 1 ml/min, t = 4.49
major enantiomer), t = 4.92 (minor enantiomer); er = 80:20.
훼] = -10.9° (c = 1.30, CH Cl ).
Zhou, Angew. Chem., Int. Ed., 2015, 54, 6531-6535; f) S.
Mannathan, S. Raoufmoghaddam, J. N. H. Reek, J. G. de
Vries, A. J. Minnaard, ChemCatChem, 2017, 9, 551-554;
g) R.-R. Liu, Y. Xu, R.-X. Liang, B. Xiang, H.-J. Xie, J.-
R. Gao, Y.-X. Jia, Org. Biomol. Chem., 2017, 15, 2711-
1
(
[
2
2
3
퐷
2
2
References
2
2
715; h) L. Hou, Y. Yuan, X. Tong, Org. Biomol. Chem.,
017, 15, 4803-4806; i) R.-X. Liang, R.-Z. Yang, R.-R.
Liu, Y.-X. Jia, Org. Chem. Front., 2018, 5, 1840-1843;
4
This article is protected by copyright. All rights reserved.

European Journal of Organic Chemistry
10.1002/ejoc.202100309
j) Z. Yuan, Z. Feng, Y. Zeng, X. Zhao, A. Lin, H. Yao,
Angew. Chem., Int. Ed., 2019, 58, 2884-2888.
1
2.W. Kong, Q. Wang, J. Zhu, J. Am. Chem. Soc., 2015, 137,
6028-16031.
1
1
1
3.B. Ju, S. Chen, W. Kong, Org. Lett., 2019, 21, 9343-9347.
4. a) L. Zhou, S. Li, B. Xu, D. Ji, L. Wu, Y. Liu, Z.-M.
Zhang, J. Zhang, Angew. Chem., Int. Ed., 2020, 59,
2
2
769-2775; b) B. Ju, S. Chen, W. Kong, Chem. Commun.,
019, 55, 14311-14314.
1
5. a) B. Zhou, H. Wang, Z.-Y. Cao, J.-W. Zhu, R.-X. Liang,
X. Hong, Y.-X. Jia, Nature Communications, 2020, 11,
4
380; b) Z. Zuo, H. Wang, Y. Diao, Y. Ge, J. Liu, X.
Luan, ACS Catal., 2018, 8, 11029-11034; c) C. Shen, N.
Zeidan, Q. Wu, C. B. J. Breuers, R.-R. Liu, Y.-X. Jia, M.
Lautens, Chem. Sci., 2019, 10, 3118-3122; d) N. Zeidan,
M. Lautens, Synthesis, 2019, 51, 4137-4146.
1
1
6. J. W. B. Fyfe, A. J. B. Watson, Chem, 2017, 3, 31-55.
7. a) M. Shimizu, T. Hiyama, Proc. Jpn. Acad., Ser. B,
2
008, 84, 75-85; b) J. H. Docherty, K. Nicholson, A. P.
Dominey, S. P. Thomas, ACS Catal., 2020, 10, 4686-
691; c) L. Zhang, X. Si, F. Rominger, A. S. K. Hashmi,
4
J. Am. Chem. Soc., 2020, 142, 10485-10493.
1
1
8. a) J. Wang, Pure Appl. Chem., 2018, 90, 617-623; b) L.
Wang, T. Zhang, W. Sun, Z. He, C. Xia, Y. Lan, C. Liu,
J. Am. Chem. Soc., 2017, 139, 5257-5264.
9. a) S. Liu, X. Zeng, B. Xu, Adv. Synth. Catal., 2018, 360,
3
249-3253; b) D. Shi, L. Wang, C. Xia, C. Liu, Angew.
Chem., Int. Ed., 2018, 57, 10318-10322; c) C. Tsukano,
M. Nakajima, S. M. Hande, Y. Takemoto, Org. Biomol.
Chem., 2019, 17, 1731-1735.
2
2
0. Z. Jiang, L. Hou, C. Ni, J. Chen, D. Wang, X. Tong,
Chem. Commun., 2017, 53, 4270-4273.
1. a) F. Ozawa, A. Kubo, T. Hayashi, J. Am. Chem. Soc.,
1
991, 113, 1417-1419; b) A. B. Dounay, L. E. Overman,
Chemical Reviews, 2003, 103, 2945-2963.
2
2
2. S. Akai, T. Tsujino, E. Akiyama, K. Tanimoto, T. Naka,
Y. Kita, J. Org. Chem., 2004, 69, 2478-2486.
3. K. Asakawa, N. Noguchi, M. Nakada, Heterocycles,
2
008, 76, 183-190.
5
This article is protected by copyright. All rights reserved.

European Journal of Organic Chemistry
10.1002/ejoc.202100309
COMMUNICATION
Palladium-catalysed carboborylation for the
synthesis of borylated indanes
Andrzej Zieba and Joel F. Hooper
R
R
Pd(OAc)2,
PPh3,
OTf
Pd2(dba)3,
L*
BPin
BPin
The interception of σ-alkyl-palladium complexes in
catalysis is a powerful strategy for the generation of
molecular complexity. We have demonstrated a
palladium catalysed carboborylation reaction for the
synthesis of borylated indanes, which proceeds in
good yields and moderate enantioselectivity.
R
B Pin
2
2
B2Pin2
6
This article is protected by copyright. All rights reserved.