Rhodium-catalyzed addition-spirocyclization of arylboronic esters containing β-aryl α,β-unsaturated ester Moiety

Article abstract of DOI:10.1055/s-0034-1378691

Abstract In this study, we developed a rhodium(I)-catalyzed spiro-cyclization. The reaction includes 1,4-rhodium migration and provides a route for forming spirocyclic 1-indanones.

Full text of DOI:10.1055/s-0034-1378691

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© Georg Thieme Verlag Stuttgart · New York
2015, 26, 1233–1237
letter
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Letter
Synlett
Rhodium-Catalyzed Addition–Spirocyclization of Arylboronic
Esters Containing β-Aryl α,β-Unsaturated Ester Moiety
Takanori Matsuda*
Satoshi Yasuoka
Shoichi Watanuki
Keisuke Fukuhara
R2
[Rh(OH)(cod)]2 (2.5 mol%)
PPh2
R3
R1
(X)n
R3
R2
PPh2 (5 mol%)
xylene, reflux
R1
Department of Applied Chemistry, Tokyo University of Science,
1–3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan
mtd@rs.tus.ac.jp
(X)n
O
CO2Me
B
O
10 examples
up to 84%
O
Received: 17.01.2015
Accepted after revision: 22.02.2015
Published online: 19.03.2015
DOI: 10.1055/s-0034-1378691; Art ID: st-2015-u0033-l
Rh(I)
+
NaBPh4
Ph
CO2Me
Abstract In this study, we developed a rhodium(I)-catalyzed spiro-
cyclization. The reaction includes 1,4-rhodium migration and provides a
route for forming spirocyclic 1-indanones.
O
Key words addition, boron, cyclization, rhodium, spiro compounds
1,4-Rhodium migration is an effective intramolecular
C–H bond-activation process,1–5 which has been used in the
formation of carbo- and heterocyclic frameworks.3 Recent-
ly, we reported that 1,1′-spirobi[indan]-3-ones were syn-
thesized using the rhodium-catalyzed addition–ring-
expansion reaction of (3-arylcyclobutylidene)acetates in-
volving successive 1,4-rhodium migration tandem (Scheme
1).4 The second 1,4-rhodium migration in this reaction oc-
curred with (1-phenylindan-1-ylmethyl)rhodium(I) species
A to generate 2-(indan-1-yl)phenylrhodium(I) B, which
subsequently reacted with the ester group to provide a
spirocyclic structure.6
Rhodium(I)-catalyzed cyclization reactions of arylbo-
ronic acids and esters bearing electrophilic functionalities
have been extensively studied.7–9 In 2012, Sarpong et al. re-
ported rhodium(I)-catalyzed asymmetric cyclization of ar-
ylboronic esters bearing a pendant ketone group (Scheme 2,
a).9 The reaction produced tertiary 1-indanols in good
yields and enantioselectivities. We anticipated that the re-
placement of the ketone group with a β-aryl α,β-unsaturat-
ed ester group would cause spirocyclization through a
mechanism analogous to our previous addition–ring-
expansion of (3-arylcyclobutylidene)acetates (Scheme 2, b).
Herein, we report rhodium(I)-catalyzed addition–spirocy-
1,4-Rh migration
MeO2C
MeO2C
Rh
Rh
A
B
Scheme 1
clization of arylboronic esters containing a pendant β-aryl
α,β-unsaturated ester moiety that produces 1,1′-spirobi[in-
dan]-3-ones through 1,4-rhodium migration.
Phenylboronic pinacol ester 1a10 bearing a β-phenyl
α,β-unsaturated ester with E stereochemistry was heated in
refluxing toluene in the presence of 5 mol% [Rh(OH)(cod)]2
(cod = cycloocta-1,5-diene; Table 1, entry 1). Spirobiinda-
none 2a was formed, as expected, in 52% yield, with an ac-
companying 24% yield of indanylacetate 3a, derived from
the protonation of organorhodium(I) species C or D. The ad-
dition of base was subsequently investigated to facilitate
the conversion of the rather robust pinacol ester. After
screening several organic and inorganic bases, higher con-
version of (E)-1a was achieved when two equivalents of te-
tramethylethylenediamine (TMEDA) was added to the reac-
tion, albeit with a worse 2a/3a ratio (Table 1, entry 2). Fur-
ther, we examined the effects of phosphine ligands on the
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 1233–1237

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T. Matsuda et al.
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action of 4a proceeded efficiently with a reduced amount of
rhodium(I) catalyst without adding TMEDA, affording 78%
yield of 2a (2a/3a = 91:9, Table 1, entry 8). Gratifyingly, the
suppression of the indane byproduct formation was finally
possible when heated in refluxing xylene, providing 84%
yield of 2a, without any detectable formation of 3a (Table 1,
entry 9).12
(a) ref. 9
R
O
Rh(I)
O
B
R
HO
O
Next, we examined the spirocyclization of various aryl-
boronic neopentyl glycol esters 1 under the conditions with
or without DPPBZ (Table 2). Phenylboronic ester 4b–d con-
taining 4-methylphenyl, 4-chlorophenyl and 4-methoxy-
phenyl groups at the β position of the α,β-unsaturated ester
moiety produced spirobiindanones 2b–d in good yields (Ta-
ble 2, entries 1–3). The addition of DPPBZ as the ligand was
found to be harmful to substrate 4e having an aryl group
with strong electron-withdrawing CF3 substituent; trifluo-
romethyl-substituted products 2e was obtained in 69%
yield without using DPPBZ (Table 2, entry 4). For the reac-
tion of 2-naphthyl derivative 4f, 1,4-rhodium migration oc-
curred selectively at the more sterically accessible site of
the aromatic ring to provide the sole product 2f in 65% yield
(Table 2, entry 5), and 3-methoxyphenyl derivative 4g simi-
larly reacted to afford 6-methoxyspirobiindanone 2g (Table
2, entry 6). The reaction of the 4-methoxyphenylboronic
ester derivative 4h produced an isomeric 5′-methoxyspiro-
biindanone 2h in 74% yield (Table 2, entry 7). Substrates 4i
and 4j, with one atom longer tethers, also participated in
the spirocyclization, producing [5.6]-spirocyclic ketones 2i
and 2j in modest yields (Table 2, entries 8 and 9).
(b) this work
Ph
Rh(I)
CO2Me
B(OR)2
O
(a)
(e)
Ph
CO2Me
Rh
MeO
(d)
ORh
(b)
(c)
MeO2C
MeO2C
Rh
Rh
D
C
(a) transmetalation
With successful demonstration of this new spiroannula-
tion reaction, the asymmetric version of this process was
examined (Scheme 3). The reaction of 4a employing (R)-
BINAP as the ligand afforded 2a in 43% yield with 52% ee.13
In summary, a spirocyclization reaction synthesizing
spirocyclic 1-indanones from phenylboronic esters, con-
taining a pendant β-phenyl α,β-unsaturated ester moiety,
was developed. The rhodium(I)-catalyzed reaction in-
volved, in sequence, transmetalation, intramolecular addi-
tion to a C=C bond, 1,4-rhodium migration, intramolecular
addition to a C=O bond, and β-oxygen elimination. We are
currently focused on further exploration and exploitation
of the migration of rhodium in synthesis toward complex
cyclic structures.
(b) intramolecular addition to C=C bond
(c) 1,4-rhodium migration
(d) intramolecular addition to C=O bond
(e) β-oxygen elimination
Scheme 2
rhodium-catalyzed cyclization of (E)-1a. The addition of
DPPE [1,2-bis(diphenylphosphino)ethane] to the reaction
improved the 2a/3a ratio to 69:31 (Table 1, entry 3). The
use of 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP)
caused 76% total yield, with a 2a/3a ratio of 59:41 (Table 1,
entry 4). Among the diphosphine ligands investigated, 1,2-
bis(diphenylphosphino)benzene (DPPBZ) exhibited superi-
or activity in the reaction, producing 2a in 63% yield
(2a/3a = 70:30, Table 1, entry 5). In contrast, the reaction of
(Z)-1a was significantly sluggish under the reaction condi-
tions; 2a was observed only in trace amounts in the crude
reaction mixture (Table 1, entry 6). The unsatisfactory re-
sults with pinacol ester 1a led us to utilize neopentyl glycol
ester 4a, since neopentyl glycol esters exhibit a greater re-
activity relative to pinacol esters.11 Although almost identi-
cal results were obtained when 4a was subjected to the re-
action conditions optimized for 1a (Table 1, entry 7), the re-
[Rh(OH)(cod)]2 (2.5 mol%)
(R)-BINAP (5 mol%)
p-xylene, reflux
O
CO2Me
B
O
O
2a
43%, 52% ee
4a
Scheme 3
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 1233–1237

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Table 1 Optimization of the Reaction Conditions for Rhodium-Catalyzed Addition–Spirocyclizationa
Ph Ph
Ph
CO2Me
Rh(I) catalyst
reflux
+
CO2Me
O
O
O
CO2Me
B
B
Ph
B
CO2Me
O
O
O
O
3a
Yield of 2a (%)b Yield of 3a (%)c
(E)-1a
1 or 4
(Z)-1a
4a
2a
Entry
[Rh(OH)(cod)]2 (mol%) Phosphine ligand (mol%) Additive (equiv)
Solvent
1
2
3
4
5
6
7
8
9
(E)-1a
(E)-1a
(E)-1a
(E)-1a
(E)-1a
(Z)-1a
4a
5
none
none
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
xylene
52
24
50
27
31
27
–
5
none
TMEDA (2)
TMEDA (2)
TMEDA (2)
TMEDA (2)
TMEDA (2)
TMEDA (2)
none
46
5
DPPE (10)
BINAP (10)
DPPBZ (10)
DPPBZ (10)
DPPBZ (10)
DPPBZ (5)
DPPBZ (5)
60
5
45
5
63
5
trace
63
5
30
8
4a
2.5
2.5
78
4a
none
84
–
a Conditions: 1a or 4a (0.10 mmol) was heated in toluene or xylene (1.0 mL) for 1–8 h in the presence of Rh catalyst.
b Isolated yield.
c Determined by 1H NMR.
Table 2 Synthesis of Spirocyclic 1-Indanones through Rhodium-Catalyzed Addition–Spirocyclization of 4a
R
Entry
Yield (%)b with DPPBZ
Yield (%)b without DPPBZ
R
O
CO2Me
O
B
O
4
2
1
2
3
4
4b R = Me
4c R = Cl
2b
2c
2d
2e
76c
68d,e
73
70
63
4d R = OMe
4e R = CF3
71
(36)
69d,e
5
65
35
O
CO2Me
O
B
2f
O
4f
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 1233–1237

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Table 2 (continued)
R
Entry
Yield (%)b with DPPBZ
Yield (%)b without DPPBZ
R
O
CO2Me
O
B
O
4
2
6
MeO
OMe
(44)
42
O
CO2Me
B
O
2g
O
4g
7
Ph
MeO
MeO
f
74g
O
CO2Me
–
B
O
O
2h
4h
CO2Me
X
X
O
Ph
B
O
O
f
8
9
4i X = CH2
4jh X = O
2i
2j
–
42
f
–
(40)d
a Arylboronic ester 4 was reacted in the presence of 5 mol% Rh catalyst in xylene (0.1 M) at 140 °C.
b Isolated yield. Yields in parentheses indicate yields determined by 1H NMR spectroscopy.
c 44% yield with the corresponding pinacol ester {5 mol% [Rh(OH)(cod)]2, toluene, reflux}.
d The reaction produced mixtures of spirobiindanones 2 and indane byproducts 3 (2c/3c = 3:1, 2e/3e = 5:1, 2j/3j = 3:1).
e Pure products of 2 were obtained after the hydrolysis of esters 3 with a base.
f Not examined.
g 46% yield with the corresponding pinacol ester {5 mol% [Rh(OH)(cod)]2, toluene, reflux}.
h Used as a mixture of stereoisomers (E/Z = 78:22).
Acknowledgment
References and Notes
This work was supported by JSPS, Japan (Grant-in-Aid for Scientific
Research (C) No. 25410054) and the Sumitomo Foundation.
(1) For reviews, see: (a) Ma, S.; Gu, Z. Angew. Chem. Int. Ed. 2005, 44,
7512. (b) Shi, F.; Larock, R. Top. Curr. Chem. 2010, 292, 123.
(2) (a) Oguma, K.; Miura, M.; Satoh, T.; Nomura, M. J. Am. Chem. Soc.
2000, 122, 10464. (b) Matsuda, T.; Shigeno, M.; Murakami, M.
J. Am. Chem. Soc. 2007, 129, 12086. (c) Sasaki, K.; Nishimura, T.;
Shintani, R.; Kantchev, E. A. B.; Hayashi, T. Chem. Sci. 2012, 3,
1278. (d) Sasaki, K.; Hayashi, T. Tetrahedron: Asymmetry 2012,
23, 373. (e) Prakash, P.; Jijy, E.; Shimi, M.; Aparna, P. S.; Suresh,
E.; Radhakrishnan, K. V. RSC Adv. 2013, 3, 19933. (f) Shintani, R.;
Iino, R.; Nozaki, K. J. Am. Chem. Soc. 2014, 136, 7849.
Supporting Information
Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0034-1378691.
S
u
p
p
ortioInfgrmoaitn
S
u
p
p
ortiInfogrmoaitn
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Letter
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(3) (a) Hayashi, T.; Inoue, K.; Taniguchi, N.; Ogasawara, M. J. Am.
Chem. Soc. 2001, 123, 9918. (b) Miura, T.; Sasaki, T.; Nakazawa,
H.; Murakami, M. J. Am. Chem. Soc. 2005, 127, 1390. (c) Shintani,
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2005, 7, 2071. (f) Shintani, R.; Tsurusaki, A.; Okamoto, K.;
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Shimada, M.; Murakami, M. Chem. Asian J. 2006, 1, 868.
(h) Shintani, R.; Takatsu, K.; Hayashi, T. Angew. Chem. Int. Ed.
2007, 46, 3735. (i) Shintani, R.; Takatsu, K.; Katoh, T.; Nishimura,
T.; Hayashi, T. Angew. Chem. Int. Ed. 2008, 47, 1447. (j) Seiser, T.;
Roth, O. A.; Cramer, N. Angew. Chem. Int. Ed. 2009, 48, 6320.
(k) Shigeno, M.; Yamamoto, T.; Murakami, M. Chem. Eur. J. 2009,
15, 12929. (l) Seiser, T.; Cramer, N. Chem. Eur. J. 2010, 16, 3383.
(m) Shintani, R.; Isobe, S.; Takeda, M.; Hayashi, T. Angew. Chem.
Int. Ed. 2010, 49, 3795. (n) Seiser, T.; Cathomen, G.; Cramer, N.
Synlett 2010, 1699. (o) Shintani, R.; Hayashi, T. Org. Lett. 2011,
13, 350. (p) Ishida, N.; Nečas, D.; Shimamoto, Y.; Murakami, M.
Chem. Lett. 2013, 42, 1076. (q) Matsuda, T.; Watanuki, S. Org.
Biomol. Chem. 2015, 13, 702.
(9) Gallego, G. M.; Sarpong, R. Chem. Sci. 2012, 3, 1338.
(10) Substrates and were synthesized by the Horner–
1
4
Wadsworth–Emmons reaction of the corresponding ketones,
which were prepared according to the literature methods.
(11) (a) Zhang, N.; Hoffman, D. J.; Gutsche, N.; Gupta, J.; Percec, V.
J. Org. Chem. 2012, 77, 5956. (b) Lennox, A. J. J.; Lloyd-Jones, G.
C. Chem. Soc. Rev. 2014, 43, 412.
(12) (E)-Methyl 5-[2-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)phe-
nyl]-3-phenylpent-2-enoate (4a): White solid; mp 104–105
°C; 1H NMR (CDCl3, 301 MHz): δ = 0.98 (s, 6 H), 3.01–3.09 (m, 2
H), 3.31–3.40 (m, 2 H), 3.65 (s, 4 H), 3.78 (s, 3 H), 6.08 (s, 1 H),
7.15–7.22 (m, 1 H), 7.32–7.42 (m, 5 H), 7.51–7.57 (m, 2 H),
7.71–7.76 (m, 1 H). 13C NMR (CDCl3, 75.6 MHz): δ = 21.8, 31.5,
34.8, 35.2, 51.1, 72.0, 116.9, 125.1, 126.9, 128.4, 128.7, 129.9,
130.3, 134.8, 141.6, 147.6, 160.8, 166.7. HRMS (ESI) calcd for
C
23H27BNaO4 [M + Na]+ 401.1895; found: 401.1895. IR: 2960,
1712, 1301, 1161, 766 cm−1
.
General Procedure for Rhodium-Catalyzed Spirocyclization
of Arylboronic Esters: To a Schlenk tube under nitrogen were
added [Rh(OH)(cod)]2 (1.2 mg, 2.6 μmol, 5 mol% Rh), 1,2-
bis(diphenylphosphino)benzene (DPPBZ, 2.3 mg, 5.2 μmol),
arylboronic ester 4 (0.100 mmol), and xylene (1.0 mL). The
solution was stirred for 5 min. at rt, and the mixture was heated
at 140 °C for 2 h. After cooling to r.t., the reaction mixture was
filtered through a plug of Florisil® washing with hexane–EtOAc
(3:1), and the filtrate was concentrated. The residue was puri-
fied by preparative TLC on silica gel (hexane–EtOAc) to afford 2.
1,1′-Spirobi[indan]-3-one (2a): According to the general pro-
cedure, 4a (37.9 mg, 0.100 mmol), [Rh(OH)(cod)]2 (1.2 mg, 2.6
μmol), and DPPBZ (2.3 mg, 5.2 μmol) were treated in xylene (1.0
mL). Purification by preparative TLC on silica gel afforded 2a
(19.7 mg, 0.084 mmol, 84%) as a colorless oil. 1H NMR (CDCl3,
300 MHz): δ = 2.37 (ddd, J = 12.7, 7.0, 5.5 Hz, 1 H), 2.52 (dt, J =
12.8, 8.2 Hz, 1 H), 2.85 (d, J = 18.9 Hz, 1 H), 3.00 (d, J = 18.9 Hz, 1
H), 3.10–3.20 (m, 2 H), 6.78 (d, J = 7.2 Hz, 1 H), 7.14 (dt, J = 0.8,
7.4 Hz, 1 H), 7.21 (dd, J = 7.3, 1.0 Hz, 1 H), 7.23–7.29 (m, 1 H),
7.32 (d, J = 7.2 Hz, 1 H), 7.37–7.46 (m, 1 H), 7.54– 7.62 (m, 1 H),
7.75–7.82 (m, 1 H); 13C NMR (CDCl3, 75.5 MHz): δ = 31.3, 42.9,
52.4, 54.5, 122.8, 123.1, 124.6, 125.1, 127.2, 127.3, 127.9, 135.4,
136.1, 143.3, 148.9, 161.5, 205.7. HRMS (ESI) calcd for
(4) Matsuda, T.; Suda, Y.; Takahashi, A. Chem. Commun. 2012, 48,
2988.
(5) For analogous 1,3- and 1,5-rhodium migrations, see: (a) Tobisu,
M.; Hasegawa, J.; Kita, Y.; Kinuta, H.; Chatani, N. Chem. Commun.
2012, 48, 11437. (b) Zhang, J.; Zhao, P.; Liu, J.-F.; Ugrinov, A.;
Pillai, A. F. X.; Sun, Z.-M. J. Am. Chem. Soc. 2013, 135, 17270.
(c) Ishida, N.; Shimamoto, Y.; Yano, T.; Murakami, M. J. Am.
Chem. Soc. 2013, 135, 19103.
(6) The corresponding intermolecular reaction was reported, see
ref. 3o.
(7) For general reviews on rhodium(I)-catalyzed addition reactions
of arylboronic acids, see: (a) Hayashi, T.; Yamasaki, K. Chem. Rev.
2003, 103, 2829. (b) Miura, T.; Murakami, M. Chem. Commun.
2007, 217. (c) Youn, S. W. Eur. J. Org. Chem. 2009, 2597.
(d) Edwards, H. J.; Hargrave, J. D.; Penrose, S. D.; Frost, C. G.
Chem. Soc. Rev. 2010, 39, 2093. (e) Tian, P.; Dong, H.-Q.; Lin,
G.-Q. ACS Catal. 2012, 2, 95.
(8) (a) Lautens, M.; Mancuso, J. Org. Lett. 2002, 4, 2105. (b) Lautens,
M.; Mancuso, J. J. Org. Chem. 2004, 69, 3478. (c) Shintani, R.;
Okamoto, K.; Hayashi, T. Chem. Lett. 2005, 34, 1294. (d) Miura,
T.; Murakami, M. Org. Lett. 2005, 7, 3339. (e) Matsuda, T.;
Makino, M.; Murakami, M. Chem. Lett. 2005, 34, 1416.
(f) Matsuda, T.; Shigeno, M.; Makino, M.; Murakami, M. Org.
Lett. 2006, 8, 3379. (g) Tseng, N.-W.; Lautens, M. J. Org. Chem.
2009, 74, 1809. (h) Shimizu, H.; Igarashi, T.; Murakami, M. Bull.
Korean Chem. Soc. 2010, 31, 1461. (i) Gourdet, B.; Rudkin, M. E.;
Lam, H. W. Org. Lett. 2010, 12, 2554. (j) Low, D. W.; Pattison, G.;
Wieczysty, M. D.; Churchill, G. H. Org. Lett. 2012, 14, 2548.
(k) Yu, Y.-N.; Xu, M.-H. J. Org. Chem. 2013, 78, 2736.
C
17H14NaO [M + Na]+ 257.0937; found: 257.0937. IR: 2948,
1716, 1602, 1236, 758 cm–1
.
(13) Asymmetric reaction: 4a (37.8 mg, 0.100 mmol),
[Rh(OH)(cod)]2 (1.1 mg, 2.4 μmol), and (R)-BINAP (3.1 mg, 5.0
μmol) were reacted in xylene (1.0 mL) at 140 °C. Purification by
preparative TLC on silica gel yielded 2a (10.1 mg, 0.043 mmol,
43%); 52% ee determined by HPLC analysis (CHIRALCEL® OJ-H
column, hexane–i-PrOH (90:10), 1.0 mL/min, tminor = 7.7 min,
tmajor = 10.0 min).
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 1233–1237

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