Regioselective synthesis of naphthalenes from modified Baylis-Hillman adducts via a Pd-catalyzed cyclization: 5-exo-carbopalladation, C(sp 3)-H activation to cyclopropane, ring-opening, and aromatization cascade

Article abstract of DOI:10.1016/j.tetlet.2010.06.046

Modified Baylis-Hillman adducts having 2-bromophenyl acetonitrile moiety at the primary position underwent a Pd-catalyzed cascade reaction to provide poly-substituted naphthalene derivatives in reasonable yields. The reaction involved a sequential 5-exo-carbopalladation, C(sp³)-H activation to cyclopropane, ring-opening and concomitant aromatization processes.

Full text of DOI:10.1016/j.tetlet.2010.06.046

Tetrahedron Letters 51 (2010) 4267–4271
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Regioselective synthesis of naphthalenes from modified Baylis–Hillman
adducts via a Pd-catalyzed cyclization: 5-exo-carbopalladation, C(sp3)–H
activation to cyclopropane, ring-opening, and aromatization cascade
*
Se Hee Kim, Hyun Seung Lee, Ko Hoon Kim, Jae Nyoung Kim
Department of Chemistry and Institute of Basic Science, Chonnam National University, Gwangju 500-757, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
Modified Baylis–Hillman adducts having 2-bromophenyl acetonitrile moiety at the primary position
underwent a Pd-catalyzed cascade reaction to provide poly-substituted naphthalene derivatives in rea-
sonable yields. The reaction involved a sequential 5-exo-carbopalladation, C(sp3)–H activation to cyclo-
propane, ring-opening and concomitant aromatization processes.
Received 31 May 2010
Accepted 7 June 2010
Available online 15 June 2010
Ó 2010 Elsevier Ltd. All rights reserved.
Chemical transformations of Baylis–Hillman adducts have
received much attention during the last two decades.1–3 Various
cyclic and acyclic compounds have been prepared from Baylis–Hill-
man adducts and their derivatives.1–3 Although Pd-catalyzed
chemical transformations of Baylis–Hillman adducts started very
recently, they have provided many interesting heterocyclic
compounds.1h,2,3,4a,b
Recently we reported the synthesis of cyclopropane-fused dihy-
drobenzofuran derivatives from the modified Baylis–Hillman ad-
ducts having 2-bromophenol moiety as shown in Scheme 1.4a
The formation of cyclopropane derivative involved a C(sp3)–H
bond activation process of the palladium intermediate.4a,5 In addi-
tion, a trace amount of benzylidene compound was formed to-
gether via a d-carbon elimination process.4a During the studies
we reasoned out that if we replace the oxygen atom to a carbon
linkage accompanying an electron-withdrawing substituent such
as a nitrile group, then the corresponding cyclopropane ring could
be opened to a dihydronaphthalene derivative, and eventually
made to form the naphthalene 4 via an aerobic oxidation process
(Scheme 1). Literature survey stated that Liron and Knochel also
observed such a ring-expansion of cyclopropane into a dihydro-
naphthalene derivative.5a In these contexts, we decided to examine
the synthesis of poly-substituted naphthalenes6,7 from the starting
materials 3.
The starting materials 3a–g were prepared by the reactions of
cinnamyl bromides 1a–d, prepared from the corresponding Bay-
lis–Hillman adducts,8 and 2-bromobenzyl derivatives 2a–d under
the influence of K2CO3 in DMF at room temperature (Scheme 2).
COOMe
Ph
Ph
Ph
MeOOC
COOMe
Ph
Pd0
BrPd
O
+
H
H
Ref. 4a
H
O
Br
O
O
(via δ-carbon
elimination)
OH
(via C-H activation)
COOMe
Ph
COOMe
COOMe
COOMe
B-H adduct
COOMe
EWG
Ph
Ph
Ph
Pd0
EWG
C H
Br
Ph
this work
H
EWG
EWG
4
3
Scheme 1.
* Corresponding author. Tel.: +82 62 530 3381; fax: +82 62 530 3389.
E-mail address: kimjn@chonnam.ac.kr (J.N. Kim).
0040-4039/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2010.06.046

4268
S. H. Kim et al. / Tetrahedron Letters 51 (2010) 4267–4271
2a-d (1.4 equiv)
K2CO3 (2.0 equiv)
DMF, rt, 2-5 h
HBr (for 1a-c)
PBr3 (for 1d)
EWG1
COOMe
CN
Br
EWG1
Br
R1
OH
R1
EWG1
EWG2
Br
Br
Br
R1
2a
2c
(For 3e)
Cs2CO3 (2.0 equiv)
CH3CN, rt, 6 h
O
O
CN
COPh
Ar
3a-g
1a-d (80-93%)
2d
2b
1a: R1 = Ph, EWG1 = COOMe
1b: R1 = Ph, EWG1 = COOEt
1c: R1 = p-tolyl, EWG1 = COOMe
1d: R1 = Me, EWG1 = COOMe
3a: 84% (1a + 2a)
3b: 86% (1b + 2a)
3c: 83% (1c + 2a)
3d: 80% (1a + 2b)
3e: 49% (1d + 2a)
3f: 94% (1a + 2c)
3g: 79% (1a + 2d)
For the structure of 3a-g,
see Table 2 and Scheme 5
Scheme 2.
Table 1
6 h). With these compounds 3a–g we examined the Pd(0)-cata-
lyzed synthesis of naphthalene derivatives.
Optimization reaction conditions of 3aa
The reaction of 3a was examined under various Pd-catalyzed
conditions, and we observed the formation of three compounds
4a, 5a and 6a, in variable yields, as shown in Table 1 and in
Scheme 3.8,9 The reaction of 3a was effective at around 80–90 °C,
and the use of DMF as a solvent was better than CH3CN (entries
1–3). The reactions at higher temperature (entries 4 and 6) or
the use of Cs2CO3 (entry 5) were not fruitful. It is interesting to note
that compound 6a was isolated as the sole product when we used
Et3N (entry 7), albeit in low yield, via the d-carbon elimination and
concomitant decarboxylation process,4 as shown in Scheme 3. Fur-
ther oxidation of 6a at the benzylic position to the corresponding
indanone derivative was not observed under the influence of a
weak base Et3N (vide infra).
The formation of naphthalene 4a could be explained as in our
previous Letter4a involving the sequential oxidative addition of
Pd(0) to form (I), 5-exo-carbopalladation to form (II), C(sp3)–H acti-
vation to give cyclopropane (III),4a,5a base-mediated ring-opening
to dihydronaphthalene (IV), and an aerobic oxidation. The aerobic
oxidation of dihydronaphthalene occurred during the reaction con-
comitantly as in our previous synthesis of quinolines.3e The forma-
tion of trace amounts of indanone 5a must be the result of a
reductive Heck type reaction caused by the solvent DMF10 to pro-
Entry Conditions
4a (%)/ 5a (%)/
6a (%)b
1
2
3
4
5
TBAB (1.0 equiv), K2CO3 (2.0. equiv),
CH3CN, reflux, 24 h
TBAB (1.0 equiv), K2CO3 (2.0. equiv),
DMF, 60 °C, 2 h
TBAB (1.0 equiv), K2CO3 (2.0 equiv),
DMF, 80–90 °C, 30 min
TBAB (1.0 equiv), K2CO3 (2.0 equiv),
DMF, 110 °C, 30 min
TBAB (1.0 equiv), Cs2CO3 (2.0 equiv), DMF,
39/8/0
c
54/7/0
24/9/0
d
80–90 °C, 30 min
d
6
7
PPh3 (20 mol %), K2CO3 (2.0 equiv), DMF, 110 °C, 1 h
PPh3 (20 mol %), Et3N (5.0 equiv), DMF, 110 °C, 1 h
0/0/34
a
b
c
Conditions: Pd(OAc)2 (10 mol %) is common.
Isolated yields.
Sluggish reaction.
d
Severe decomposition was observed.
The yields of 3a–g were good (79–94%) except 3e. The yield of 3e
was low due to the formation of many intractable side products
under the same conditions. However, a reasonable yield of 3e
(49%) was obtained under the influence of Cs2CO3 in CH3CN (rt,
COOMe
CN
Ph
COOMe
Ph
COOMe
Ph
Ph
Conditions
+
+
Br
NC
O
CN
5a
6a
4a
3a
O
COOMe
C(sp3)-H
ring
expansion
OMe
Ph
aerobic
Ph
oxidation
Pd0
activation
4a
H
(IV)
(III)
NC
Ph
CN
PdBr
COOMe
Ph
COOMe
CN
COOMe
reductive
quenching
aerobic
Ph
5-exo-trig
oxidation
5a
DMF/base
PdBr
(V)
NC
Pd
NC
(II)
Me
O
O
Br
Ph
(I)
δ-carbon
elimination
6a
NC
Scheme 3.

S. H. Kim et al. / Tetrahedron Letters 51 (2010) 4267–4271
4269
Table 2
Synthesis of poly-substituted naphthalenes 4a–fa
Entry
Substrate
Products (%)
COOMe
CN
COOMe
Ph
MeOOC
EtOOC
1
Br
O
O
CN
5a (7)
4a (54)
3a
COOEt
CN
COOEt
Ph
2
Br
CN
5b (9)
4b (53)
3b
COOMe
CN
COOMe
Ar
MeOOC
Ar
Ar
3b
Br
O
CN
5c (7)
4c (44)
3c
3d
COOMe
CN
COOMe
O
Ph
MeOOC
O
O
O
Br
4
CN
O
4d (36)
O
5d (6)
O
COOMe
COOMe
Me
MeOOC
Me
CN
5
6
Br
O
CN
5e (23)
4e (21)
3e
3f
COOMe
COOMe
Ph
MeOOC
COOMe
Br
COOMe
5f (-)
COOMe
4f (41)
a
Conditions: substrate 3 (1.0 equiv), Pd(OAc)2 (10 mol %), TBAB (1.0 equiv), K2CO3 (2.0 equiv), DMF, 80–90 °C, 30 min.
Ar is 4-tolyl.
b
EtO
O
Ph
δ = 7.42-7.48 (m)
Ph
H
H
Ph
(i) β-H elimination
(ii) air oxidation
δ = 7.71 (t)
δ = 7.75 (t)
δ = 8.03 (d)
δ = 8.31 (d)
BrPd
MeOOC
MeOOC
H
H
H
6-endo-trig
3b
nOe 2%
H
CN
δ = 7.97 (s)
CN
CN
7 (not formed)
4b
Scheme 4.
COOMe
COPh
Br
Ph
Pd(OAc)2 (10 mol%)
TBAB (1.0 equiv)
Pd(OAc)2 (5 mol%)
PPh3 (10 mol%)
decomposition
K2CO3 (2.0 equiv)
DMF, 80-90oC, 1 h
Et3N (2.0 equiv)
DMF, 110 oC, 40 min
Ph
8 (67%)
O
3g
Scheme 5.
duce (V), and the following base-mediated aerobic oxidation to 5a.
Similar aerobic oxidation of benzylic cyanides under basic condi-
tions has been reported.11
We chose the conditions in entry 3 (Table 1) and carried out the
synthesis of naphthalenes 4a–f, as shown in Table 2. Naphthalene
derivatives 4a–f were obtained in reasonable yields (21–54%)

4270
S. H. Kim et al. / Tetrahedron Letters 51 (2010) 4267–4271
along with trace amounts of indanone derivatives 5a–d (6–9%).9 It is
interesting to note that vinyl compound 5e was isolated in 23% yield
for the ethylidene compound 3e via the usual b-H elimination pro-
cess of the palladium intermediate (entry 5). Ester derivative 3f (en-
try 6) also produced naphthalene 4f in a reasonable yield (41%);
however, we failed to isolate the corresponding indane derivative 5f.
The structure of naphthalene was confirmed unequivocally by
NOE experiments, as shown in Scheme 4, using compound 4b as
an example. Irradiation of the singlet of naphthalene 4b at
7.97 ppm showed a NOE increment of the aromatic protons of
the phenyl group (7.42–7.48 ppm). As shown in Scheme 4, naph-
thalene 7 has to be formed if the carbopalladation occurred in a
6-endo mode. From the NOE results, the possibility of 6-endo-car-
bopalladation could be ruled out.
The benzoyl derivative 3g showed the formation of many
intractable compounds under the optimized conditions (entry 3
in Table 1), and we failed to obtain the corresponding naphthalene
derivative 4g. However, the reaction under the conditions using
Et3N (entry 7 in Table 1) afforded compound 8 in 67% yield via
the d-carbon elimination process,4,9 as shown in Scheme 5.
In summary, we disclosed a new synthesis of poly-substituted
naphthalenes starting from the Baylis–Hillman adducts having 2-
bromophenyl acetonitrile moiety at the primary position via a
Pd-catalyzed cascade reaction involving a sequential 5-exo-carbo-
palladation, C(sp3)–H activation to cyclopropane, ring-opening
and aromatization processes.
2006, 45, 3462–3465; (d) Dyker, G. Angew. Chem., Int. Ed. 1994, 33, 103–105; (e)
Dyker, G. J. Org. Chem. 1993, 58, 6426–6428; (f) Dyker, G. Angew. Chem., Int. Ed.
1992, 31, 1023–1025; (g) Hitce, J.; Retailleau, P.; Baudoin, O. Chem. Eur. J. 2007,
13, 792–799; (h) Baudoin, O.; Herrbach, A.; Gueritte, F. Angew. Chem., Int. Ed.
2003, 42, 5736–5740.
6. For some leading references to naphthalene synthesis, see: (a) Asao, N.;
Takahashi, K.; Lee, S.; Kasahara, T.; Yamamoto, Y. J. Am. Chem. Soc. 2002, 124,
12650–12651; (b) Asao, N.; Nogami, T.; Lee, S.; Yamamoto, Y. J. Am. Chem. Soc.
2003, 125, 10921–10925; (c) Barluenga, J.; Vazquez-Villa, H.; Ballesteros, A.;
Gonzalez, J. M. Org. Lett. 2003, 5, 4121–4123; (d) Barluenga, J.; Vazquez-Villa,
H.; Merino, I.; Ballesteros, A.; Gonzalez, J. M. Chem. Eur. J. 2006, 12, 5790–5805;
(e) Patil, N. T.; Konala, A.; Singh, V.; Reddy, V. V. N. Eur. J. Org. Chem. 2009,
5178–5184; (f) Shi, M.; Lu, J.-M. J. Org. Chem. 2006, 71, 1920–1923; (g) Jiang, X.;
Kong, W.; Chen, J.; Ma, S. Org. Biomol. Chem. 2008, 6, 3606–3610; (h) Dudnik, A.
S.; Schwier, T.; Gevorgyan, V. Tetrahedron 2009, 65, 1859–1870; (i)
Balamurugan, R.; Gudla, V. Org. Lett. 2009, 11, 3116–3119.
7. For our recent synthesis of naphthalene derivatives, see: (a) Kim, S. H.; Kim, Y.
M.; Lee, H. S.; Kim, J. N. Tetrahedron Lett. 2010, 51, 1592–1595; (b) Lee, K. Y.;
Kim, S. C.; Kim, J. N. Tetrahedron Lett. 2006, 47, 977–980; (c) Gowrisankar, S.;
Kim, K. H.; Kim, J. N. Bull. Korean Chem. Soc. 2008, 29, 2537–2539; (d) Im, Y. J.;
Lee, K. Y.; Kim, T. H.; Kim, J. N. Tetrahedron Lett. 2002, 43, 4675–4678; (e)
Gowrisankar, S.; Lee, H. S.; Kim, J. N. Tetrahedron Lett. 2007, 48, 3105–3108.
8. For the synthesis of cinnamyl bromide derivatives in a stereoselective manner
from Baylis–Hillman adducts, see: (a) Gowrisankar, S.; Kim, S. H.; Kim, J. N. Bull.
Korean Chem. Soc. 2009, 30, 726–728. and further references cited therein; (b)
Basavaiah, D.; Reddy, K. R.; Kumaragurubaran, N. Nat. Protoc. 2007, 2, 2665–
2676; (c) Das, B.; Banerjee, J.; Ravindranath, N. Tetrahedron 2004, 60, 8357–
8361; (d) Fernandes, L.; Bortoluzzi, A. J.; Sa, M. M. Tetrahedron 2004, 60, 9983–
9989; (e) Sa, M. M.; Ramos, M. D.; Fernandes, L. Tetrahedron 2006, 62, 11652–
11656; (f) Deng, J.; Hu, X.-P.; Huang, J.-D.; Yu, S.-B.; Wang, D.-Y.; Duan, Z.-C.;
Zheng, Z. J. Org. Chem. 2008, 73, 2015–2017; (g) Lee, K. Y.; Lee, Y. J.; Kim, J. N.
Bull. Korean Chem. Soc. 2007, 28, 143–146; (h) Lee, K. Y.; Park, D. Y.; Kim, J. N.
Bull. Korean Chem. Soc. 2006, 27, 1489–1492.
9. Typical procedure for the preparation of starting material 3a: A mixture of 1a
(255 mg, 1.0 mmol), 2a (275 mg, 1.4 mmol), and K2CO3 (277 mg, 2.0 mmol) in
DMF (3 mL) was stirred at room temperature for 2 h. The usual aqueous
workup and column chromatographic purification process (hexanes/diethyl
ether, 15:1) afforded compound 3a as a colorless oil, 312 mg (84%). Other
compounds were prepared similarly and the selected spectroscopic data of 3a,
3b, and 3g are as follows.
Acknowledgments
This research was supported by Basic Science Research Program
through the National Research Foundation of Korea (NRF) funded
by the Ministry of Education, Science and Technology (2009-
0070633). Spectroscopic data was obtained from the Korea Basic
Science Institute, Gwangju branch.
Compound 3a: 84%; colorless oil; IR (film) 2242, 1713, 1436, 1263 cmÀ1 1H NMR
;
(CDCl3, 300 MHz) d 3.07–3.20 (m, 2H), 3.87 (s, 3H), 4.77 (t, J = 8.1 Hz, 1H), 7.10–
7.53 (m, 9H), 7.93 (s, 1H); 13C NMR (CDCl3, 75 MHz) d 31.72, 35.91, 52.30, 119.77,
123.13, 127.54, 128.20, 128.55, 128.63 (2C), 129.30, 129.78, 133.24, 134.71,
134.85, 144.15, 167.59; ESIMS m/z 392 (M++Na), 394 (M++2+Na). Anal. Calcd for
C
19H16BrNO2: C, 61.64; H, 4.36; N, 3.78. Found: C, 61.95; H, 4.45; N, 3.56.
Compound 3b: 86%; colorless oil; IR (film) 2242, 1705, 1472, 1260 cmÀ1 1H NMR
;
References and notes
(CDCl3, 300 MHz) d 1.39 (t, J = 7.2 Hz, 3H), 3.07–3.20 (m, 2H), 4.32 (q, J = 7.2 Hz,
2H), 4.78 (t, J = 8.1 Hz, 1H), 7.10–7.52 (m, 9H), 7.93 (s, 1H); 13C NMR (CDCl3,
75 MHz) d 14.31, 31.69, 35.93, 61.33, 119.81, 123.15, 127.84, 128.21, 128.54,
128.56, 128.63, 129.30, 129.77, 133.23, 134.81, 134.91, 143.89, 167.12; ESIMS m/
z 406 (M++Na), 408 (M++2+Na). Anal. Calcd for C20H18BrNO2: C, 62.51; H, 4.72; N,
3.65. Found: C, 62.76; H, 4.69; N, 3.51.
1. For the general review on Baylis–Hillman reaction, see: (a) Basavaiah, D.; Rao,
A. J.; Satyanarayana, T. Chem. Rev. 2003, 103, 811–891; (b) Singh, V.; Batra, S.
Tetrahedron 2008, 64, 4511–4574; (c) Kim, J. N.; Lee, K. Y. Curr. Org. Chem. 2002,
6, 627–645; (d) Lee, K. Y.; Gowrisankar, S.; Kim, J. N. Bull. Korean Chem. Soc.
2005, 26, 1481–1490; (e) Langer, P. Angew. Chem., Int. Ed. 2000, 39, 3049–3052;
(f) Radha Krishna, P.; Sachwani, R.; Reddy, P. S. Synlett 2008, 2897–2912; (g)
Declerck, V.; Martinez, J.; Lamaty, F. Chem. Rev. 2009, 109, 1–48; (h)
Gowrisankar, S.; Lee, H. S.; Kim, S. H.; Lee, K. Y.; Kim, J. N. Tetrahedron 2009,
65, 8769–8780.
2. For the recent Pd-catalyzed reactions of modified Baylis–Hillman adducts, see:
(a) Vasudevan, A.; Tseng, P.-S.; Djuric, S. W. Tetrahedron Lett. 2006, 47, 8591–
8593; (b) Coelho, F.; Veronese, D.; Pavam, C. H.; de Paula, V. I.; Buffon, R.
Tetrahedron 2006, 62, 4563–4572; (c) Kohn, L. K.; Pavam, C. H.; Veronese, D.;
Coelho, F.; De Carvalho, J. E.; Almeida, W. P. Eur. J. Med. Chem. 2006, 41, 738–
744; (d) Liu, H.; Yu, J.; Wang, L.; Tong, X. Tetrahedron Lett. 2008, 49, 6924–6928;
(e) Szlosek-Pinaud, M.; Diaz, P.; Martinez, J.; Lamaty, F. Tetrahedron 2007, 63,
3340–3349; (f) Jellerichs, B. G.; Kong, J.-R.; Krische, M. J. J. Am. Chem. Soc. 2003,
125, 7758–7759. further references were compiled in Ref. 1h.
3. For our contributions on Pd-catalyzed reactions of modified Baylis–Hillman
adducts, see: (a) Kim, K. H.; Lee, H. S.; Kim, S. H.; Kim, S. H.; Kim, J. N. Chem. Eur.
J. 2010, 16, 2375–2380; (b) Kim, J. M.; Kim, S. H.; Lee, H. S.; Kim, J. N.
Tetrahedron Lett. 2009, 50, 1734–1737; (c) Kim, K. H.; Kim, E. S.; Kim, J. N.
Tetrahedron Lett. 2009, 50, 5322–5325; (d) Lee, H. S.; Kim, S. H.; Kim, T. H.; Kim,
J. N. Tetrahedron Lett. 2008, 49, 1773–1776; (e) Gowrisankar, S.; Lee, H. S.; Kim,
J. M.; Kim, J. N. Tetrahedron Lett. 2008, 49, 1670–1673; (f) Gowrisankar, S.; Lee,
H. S.; Lee, K. Y.; Lee, J.-E.; Kim, J. N. Tetrahedron Lett. 2007, 48, 8619–8622; (g)
Kim, J. M.; Kim, K. H.; Kim, T. H.; Kim, J. N. Tetrahedron Lett. 2008, 49, 3248–
3251; (h) Lee, H. S.; Kim, S. H.; Gowrisankar, S.; Kim, J. N. Tetrahedron 2008, 64,
7183–7190; (i) Gowrisankar, S.; Kim, K. H.; Kim, S. H.; Kim, J. N. Tetrahedron
Lett. 2008, 49, 6241–6244.
Compound 3g: 79%; white solid, mp 62–64 °C, IR (KBr) 1710, 1683, 1445, 1436,
1252, 1208 cmÀ1 1H NMR (CDCl3, 300 MHz) d 3.19–3.34 (m, 2H), 3.80 (s, 3H),
;
5.43 (dd, J = 9.9 and 4.5 Hz, 1H), 6.83–6.96 (m, 5H), 7.19–7.22 (m, 3H), 7.33–7.38
(m, 2H), 7.44–7.49 (m, 2H), 7.69 (s, 1H), 7.92–7.95 (m, 2H); 13C NMR (CDCl3,
75 MHz) d 30.54, 50.21, 52.09, 125.05, 127.67, 127.83, 128.17, 128.48, 128.50,
128.55, 128.68, 129.57, 129.65, 132.87, 133.03, 135.40, 136.03, 137.67, 141.99,
168.49, 199.10; ESIMS m/z 471 (M++Na), 473 (M++2+Na). Anal. Calcd for
C
25H21BrO3: C, 66.82; H, 4.71. Found: C, 66.97; H, 4.93.
Typical procedure for the preparation of 4a: A stirred mixture of 3a (185 mg,
0.5 mmol), Pd(OAc)2 (12 mg, 10 mol %), TBAB (162 mg, 0.5 mmol), and K2CO3
(139 mg, 1.0 mmol) in DMF (1 mL) was heated to 80–90 °C under nitrogen
atmosphere for 30 min. After the usual aqueous workup and column
chromatographic purification process (hexanes/EtOAc, 20:1), compounds 4a
(78 mg, 54%) and 5a (10 mg, 7%) were obtained. Other compounds were
prepared similarly and the selected spectroscopic data of 4a, 5a, 4b, 5b, 5e, 6a,
and 8 are as follows.
Compound 4a: 54%; white solid, mp 136–138 °C; IR (KBr) 2226, 1732,
1236 cmÀ1 1H NMR (CDCl3, 300 MHz) d 3.73 (s, 3H), 7.40–7.78 (m, 5H), 7.68–
;
7.78 (m, 2H), 7.98 (s, 1H), 7.98–8.01 (m, 1H), 8.30–8.33 (m, 1H); 13C NMR (CDCl3,
75 MHz) d 52.60, 112.08, 117.07, 125.43, 125.91, 128.37, 128.47, 128.79, 128.89,
128.97, 129.77, 131.21, 133.93, 134.70, 137.19, 138.65, 168.56; ESIMS m/z 310
(M++Na). Anal. Calcd for C19H13NO2: C, 79.43; H, 4.56; N, 4.88. Found: C, 79.71; H,
4.66; N, 4.54.
Compound 5a: 7%; colorless oil; IR (film) 1720, 1241, 1207 cmÀ1 1H NMR (CDCl3,
;
300 MHz) d 2.76 (d, J = 18.9 Hz, 1H), 3.19 (d, J = 13.8 Hz, 1H), 3.26 (d, J = 18.9 Hz,
1H), 3.57 (d, J = 13.8 Hz, 1H), 3.74 (s, 3H), 6.91–6.94 (m, 2H), 7.17–7.21 (m, 2H),
7.42–7.48 (m, 2H), 7.65–7.70 (m, 2H), 7.80–7.82 (m, 1H); 13C NMR (CDCl3,
75 MHz) d 44.61, 44.81, 52.79, 54.18, 123.60, 125.96, 127.12, 128.34, 128.93,
129.85, 134.81, 136.10, 136.23, 154.86, 173.76, 203.47; ESIMS m/z 303 (M++Na).
Anal. Calcd for C18H16O3: C, 77.12; H, 5.75. Found: C, 77.43; H, 5.98.
4. For the similar examples on d-carbon elimination, see: (a) Kim, H. S.;
Gowrisankar, S.; Kim, S. H.; Kim, J. N. Tetrahedron Lett. 2008, 49, 3858–3861;
(b) Kim, H. S.; Lee, H. S.; Kim, S. H.; Kim, J. N. Tetrahedron Lett. 2009, 50, 3154–
3157; (c) Kim, H. S.; Gowrisankar, S.; Kim, E. S.; Kim, J. N. Tetrahedron Lett. 2008,
49, 6569–6572. and further references were cited therein.
Compound 4b: 53%; white solid, mp 83–85 °C; IR (KBr) 2226, 1728, 1235 cmÀ1
;
5. For the similar examples on C(sp3)–H bond activation, see: (a) Liron, F.;
Knochel, P. Tetrahedron Lett. 2007, 48, 4943–4946; (b) Ren, H.; Li, Z.; Knochel, P.
Chem. Asian J. 2007, 2, 416–433; (c) Ren, H.; Knochel, P. Angew. Chem., Int. Ed.
1H NMR (CDCl3, 300 MHz) d 1.01 (t, J = 7.2 Hz, 3H), 4.19 (q, J = 7.2 Hz, 2H), 7.42–
7.48 (m, 5H), 7.71 (t, J = 7.8 Hz, 1H), 7.75 (t, J = 7.8 Hz, 1H), 7.97 (s, 1H), 8.03 (d,

S. H. Kim et al. / Tetrahedron Letters 51 (2010) 4267–4271
4271
J = 8.1 Hz, 1H), 8.31 (d, J = 8.4 Hz, 1H); 13C NMR (CDCl3, 75 MHz) d 13.63, 61.88,
111.88, 117.10, 125.39, 125.89, 128.39, 128.53, 128.67, 128.83, 128.92, 129.72,
131.22, 133.92, 134.97, 137.21, 138.73, 167.95; ESIMS m/z 324 (M++Na).
(CDCl3, 75 MHz) d 32.72, 36.00, 120.72, 120.77, 121.57, 125.04, 127.23, 128.53,
128.63, 129.10, 129.17, 136.89, 138.30, 138.47, 141.72; ESIMS m/z 254 (M++Na).
Anal. Calcd for C17H13N: C, 88.28; H, 5.67; N, 6.06. Found: C, 88.13; H, 5.78; N,
5.95.
Compound 5b: 9%; colorless oil; IR (film) 1720, 1234, 1195 cmÀ1 1HNMR (CDCl3,
;
300 MHz) d 1.25 (t, J = 7.2 Hz, 3H), 2.75 (d, J = 18.9 Hz, 1H), 3.19 (d, J = 13.5 Hz,
1H), 3.28 (d, J = 18.9 Hz, 1H), 3.56 (d, J = 13.5 Hz, 1H), 4.19 (q, J = 7.2 Hz, 2H),
6.92–6.97 (m, 2H), 7.15–7.20 (m, 3H), 7.43–7.48 (m, 1H), 7.65–7.70 (m, 2H),
7.80–7.83 (m, 1H); 13C NMR (CDCl3, 75 MHz) d 14.04, 44.59, 44.81, 54.17, 61.81,
123.57, 125.93, 127.08, 128.31, 128.87, 129.89, 134.75, 136.21, 136.25, 155.06,
173.23, 203.62; ESIMS m/z 317 (M++Na).
Compound 8: 67%; yellow solid; mp 106–108 °C; IR (KBr) 1682, 1596, 1447,
1225 cmÀ1 1H NMR (CDCl3, 300 MHz) d 3.36–3.60 (m, 2H), 5.17 (dd, J = 8.4 and
;
5.1 Hz, 1H), 7.02 (t, J = 2.1 Hz, 1H), 7.09–7.67 (m, 13H), 8.03–8.06 (m, 1H); 13C
NMR (CDCl3, 75 MHz) d 34.98, 50.86, 120.11, 120.59, 125.58, 126.59, 127.88,
128.34, 128.44, 128.59, 128.84, 129.04, 133.34, 136.77, 137.73, 141.35, 142.84,
142.91, 199.27; ESIMS m/z 333 (M++Na). Anal. Calcd for C23H18O: C, 89.00; H,
5.85. Found: C, 88.85; H, 5.92.
Compound 5e: 23%; colorless oil; IR (film) 1732, 1721, 1248, 1236 cmÀ1 1H NMR
;
(CDCl3, 300 MHz) d 2.82 (d, J = 18.9 Hz, 1H), 3.49 (d, J = 18.9 Hz, 1H), 3.75 (s, 3H),
4.98 (d, J = 17.1 Hz, 1H), 5.21 (d, J = 10.5 Hz, 1H), 6.39 (dd, J = 17.1 and 10.5 Hz,
1H), 7.46–7.51 (m, 1H), 7.64–7.72 (m, 2H), 7.75–7.79 (m, 1H); 13C NMR (CDCl3,
75 MHz) d 47.21, 53.03, 55.73, 115.45, 123.74, 126.96, 129.00, 134.87, 135.98,
139.08, 153.49, 172.85, 203.18; ESIMS m/z 239 (M++Na). Anal. Calcd for
10. For the reductive Heck type quenching caused by DMF, see: (a) Zawisza, A. M.;
Muzart, J. Tetrahedron Lett. 2007, 48, 6738–6742; (b) Li, J.; Hua, R.; Liu, T. J. Org.
Chem. 2010, 75, 2966–2970; (c) Legros, J.-Y.; Primault, G.; Toffano, M.; Riviere,
M.-A.; Fiaud, J.-C. Org. Lett. 2000, 2, 433–436; (d) Brenda, M.; Knebelkamp, A.;
Greiner, A.; Heitz, W. Synlett 1991, 809–810.
C
13H12O3: C, 72.21; H, 5.59. Found: C, 72.38; H, 5.77.
11. For the similar oxidative decyanation of secondary nitriles to ketones, see: (a)
Kulp, S. S.; McGee, M. J. J. Org. Chem. 1983, 48, 4097–4098; (b) Freerksen, R. W.;
Selikson, S. J.; Wroble, R. R. J. Org. Chem. 1983, 48, 4087–4096.
Compound 6a: 34%; yellow oil; IR (film) 2240, 1491, 1459, 1261 cmÀ1
;
1H NMR
(CDCl3, 300 MHz) d 3.35–3.61 (m, 2H), 4.26 (dd, J = 8.7 and 6.0 Hz, 1H), 7.01 (t,
J = 2.4 Hz, 1H), 7.23–7.41 (m, 7H), 7.48–7.52 (m, 1H), 7.62–7.65 (m, 1H); 13C NMR