Palladacycle as highly efficient catalyst for ring opening of oxabicyclic alkenes with organozinc halides

Article abstract of DOI:10.1016/j.jorganchem.2006.12.039

Ring opening reaction of oxabicylic alkenes 4 with in situ prepared organozinc halides 5 was catalyzed by palladacycle 3 with high efficiency. Good yields of the corresponding 1,2-dihydronaphth-1-ols (6) were provided when as low as 0.05 mol% of palladacycle 3 was used. ³¹P NMR study showed that the skeleton of 3 remained intact in the reaction, which implied that palladacycle 3 did not serve as a catalyst precursor but a catalyst in the reaction.

Full text of DOI:10.1016/j.jorganchem.2006.12.039

Journal of Organometallic Chemistry 692 (2007) 1912–1919
www.elsevier.com/locate/jorganchem
Palladacycle as highly efficient catalyst for ring opening of oxabicyclic
alkenes with organozinc halides
b
a
a,b,
*
Ting-Ke Zhang , Ke Yuan , Xue-Long Hou
a
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
354 Feng Lin Road, Shanghai 200032, China
b
Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
354 Feng Lin Road, Shanghai 200032, China
Received 6 November 2006; received in revised form 15 December 2006; accepted 22 December 2006
Available online 11 January 2007
Abstract
Ring opening reaction of oxabicylic alkenes 4 with in situ prepared organozinc halides 5 was catalyzed by palladacycle 3 with high
efficiency. Good yields of the corresponding 1,2-dihydronaphth-1-ols (6) were provided when as low as 0.05 mol% of palladacycle 3 was
used. 31P NMR study showed that the skeleton of 3 remained intact in the reaction, which implied that palladacycle 3 did not serve as a
catalyst precursor but a catalyst in the reaction.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Ring opening reaction; Palladium; Palladacycle; Oxabicyclic alkene; Organozinc halides; C–C bond formation
1. Introduction
lyst precursors [2d,4m,7] and are mainly used in Heck-type
reactions and coupling reactions [2–6], though there have
been some reports using palladacycle as transition metal
catalyst [5]. To explore the applications of palladacycles
as real transition metal catalyst in other C–C bond forma-
tion is still highly demanded.
Organopalladium complexes play an important role in
carbon–carbon bond forming reactions because of their
versatility, compatibility with most of functional groups
and relative low toxicity [1]. Among them, palladacycles
have attracted more attentions as their enormous superior-
ity in many aspects [2]. Palladacycles are readily prepared,
air and moisture stable. Since Hermann and Beller demon-
strated the extremely high catalytic activity of cyclopalla-
dated tri-o-tolylphosphine in Heck reaction [3], many
palladacycles have been synthesized and used as highly effi-
cient catalysts in carbon–carbon bond forming reactions
[2–6]. Some of them achieved extremely high TONs (up
to 1010 TON) [6]. In spite of palladacycles have showed
many advantages in catalysis, they usually served as cata-
The ring opening of oxabicyclic compounds is an useful
protocol in the synthesis of cyclic compounds with multiple
stereocenters [8]. Many metal complexes are suitable
catalysts for regio- and enantioselective nucleophilic ring
opening of oxabicylic alkenes using dialkylzinc reagents,
Grignard reagents and many others as nucleophile [9].
Usually 1 mol% or more amount of catalysts are needed
[10]. However, no report using palladacycle as catalyst
appeared in this reaction. During the course of studies on
the synthesis and application of ligands in asymmetric
catalysis [11], we found that the palladacycle dimer 2 with
an oxazoline moiety and two methyl groups situated at the
benzylic position was highly efficient catalyst in the hydro-
arylation of a variety of bicyclic alkenes [12]. Further stud-
ies showed that palladacycle monomer 3 is a more excellent
catalyst for the ring-opening of oxabicyclic alkenes with
*
Corresponding author. Address: State Key Laboratory of Organome-
tallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese
Academy of Sciences, 354 Feng Lin Road, Shanghai 200032, China.
Tel.: +86 21 5492 5144; fax: +86 21 5492 5100.
E-mail address: xlhou@mail.sioc.ac.cn (X.-L. Hou).
0022-328X/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.12.039

T.-K. Zhang et al. / Journal of Organometallic Chemistry 692 (2007) 1912–1919
1913
in situ prepared organozinc halides [11d]. High yields of
products were afforded using as low as 0.05 mol% amount
of palladacycle 3 as catalyst. 31P NMR study showed that
palladacycle 3 served as a real catalyst, not the catalyst pre-
cursor. Herein we would like to report our results with
these aspects.
2. Results and discussion
Previously, we reported the synthesis of palladacycle
dimer 2 from bromophenyl acetic acid derivative 1 in high
yield [12] which reacted with triphenylphosphine provided
palladacycle monomer 3 in high yield (Scheme 1). Its struc-
ture was determined by X-ray diffraction (Fig. 1).
Reaction of 7-oxabenzonorbornadiene (4a) with in situ
prepared benzylzinc bromide 5a in dichloromethane at
room temperature afforded ring-opening product 6aa in
95% yield in 15 min when 5 mol% of palladacycle mono-
mer 3 was used as catalyst (Eq. (1)). However, only 10%
yield of 6aa was provided accompanied the formation of
palladium black when palladacycle dimer 2 was used.
The yield of 6aa did not increase even the reaction time
prolonged to 10 h. To test the efficiency of the catalyst,
the reaction was carried out using different amount of cat-
alyst 3 in different solvents. The results are summarized in
Table 1.
Fig. 1. ORTEP drawing of palladacycle monomer 3. Hydrogens are
omitted for clarity. Selected bond distances (A) and angles (ꢁ): Pd–C (1)
2.011 (3); Pd–N (1) 2.070 (2); Pd–P (1) 2.2525 (7); Pd–Br 2.5413 (4); C (1)–
Pd–N (1) 84.68 (11); C (1)–Pd–P (1) 92.79 (8); N (1)–Pd–P (1) 170.04 (7); C
(1)–Pd–Br 169.87 (8); N (1)– Pd–Br 92.32 (7); P (1)–Pd–Br 91.47 (2).
˚
OH
Palladacycle
(5 mol%)
toluene is the best one among the solvents tested. High
yield of product 6aa was provided when the reaction pro-
ceeded at 45 ꢁC in toluene (entry 4), only moderate yield
of 6aa was given while that in THF (entry 7), and that in
CHCl3 and CH3CN delivered the product 6aa with con-
comitance of a-naphthol 7, though the yields were high (en-
tries 5 and 6). A complex mixture was given when the
reaction proceeded in DMF and DMSO (not showed in
Table 1). Catalytic activity was even higher when the reac-
tion run in toluene at 80 ꢁC. If the amount of catalyst de-
creased to 0.05 mol%, ring opening product 6aa was
provided in 77% yield (entry 9). Further decrease of the
catalyst loading to 0.005 mol% led to the incomplete of
the reaction, giving 36% yield of 6aa (entry 10). Raise the
reaction temperature made the substrate decomposition
[9k]. However, the [a]D values of the products were almost
zero in all cases.
Ph
O
+
Ph
ZnBr
CH2Cl2
r.t.
6aa
4a
5a
Palladacycle 2 10% yield
Palladacycle 3 95% yield
ð1Þ
From Table 1, it can be seen that the temperature has great
impact on the reaction. Higher temperature is favorable.
Using 0.5 mol% of 3 in CH2Cl2, the reaction gave the prod-
uct in 87% yield in 2 h at room temperature while the yield
increased to 91% in 25 min when the reaction proceeded at
reflux (entry 1 vs. entry 3). Solvent effect study showed that
O
Using 0.05 mol% of palladacycle 3 in toluene at 80 ꢁC,
reactions of a variety of bicyclic alkenes 4 with different
benzylzinc bromide derivatives 5 were carried out (Eq.
(2)), the results were summarized in Table 2.
COOH
4 steps
N
90%
Pd
Br
Br
2
1
2
R1
R3
O
R1
R3 OH
O
palladacycle 3
R2
R2
R2
R2
PPh3
98%
(0.05 mol%)
Ar
Ar
+
ZnBr
N
toluene
80 °C
Pd
R1
R3
R1
R3
Ph3P
Br
4
5
6
3
ð2Þ
Scheme 1. Synthesis of palladacycle monomer 3.

1914
T.-K. Zhang et al. / Journal of Organometallic Chemistry 692 (2007) 1912–1919
Table 1
alkene 4e as starting material (entry 14). Ring opening
products 6da and 6ea were afforded in 82% and 65% yields
respectively if 0.5 mol% of catalyst was used (entries 13 and
15).
Ring-opening reaction of oxabicyclic alkene 4a with BnZnBr catalyzed by
palladacycle 3a
Entry
3
Solvent Temperature
Time
Yield (%)b
(mol%)
(ꢁC)
OH
OH
1
2
3
4
5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
CH2Cl2 r.t.
2 h
10 h
87
34
Br
Br
CH2Cl2
0
CH2Cl2 Reflux
Toluene 45
25 min 91
30 min 95
30 min 93c
30 min 90c
30 min 42
CHCl3
CH3CN 45
THF 45
45
7
6
7
8
8
9
10
11
a
0.05
0.05
0.005
0.005
CH2Cl2 Reflux
Toluene 80
Toluene 80
22 h
1 h
20 h
15 h
22
77
36
Ring opening product 10 was delivered in 43% yield
when oxabicyclic alkene 9 reacted with BnZnBr 5a in the
presence of 0.5 mol% of catalyst 3 (Eq. (3)), but no prod-
ucts were given when azabicyclic alkenes were used, per-
haps due to their low reactivity [9b].
Toluene 100
Decomposition
Oxabicyclic alkene 4a (0.5 mmol), BnZnBr 5a (1 mmol) and catalyst in
solvent (2 mL).
b
Isolated yields.
a-Naphthol as byproduct (ꢀ1% determined by 1H NMR).
c
OH
BnZnBr 5a
MeOOC
MeOOC
MeOOC
MeOOC
3 (0.5 mol%)
Ph
O
ð3Þ
toluene
80 °C
Table 2
Palladacycle 3 catalyzed ring-opening of oxabicyclic alkenes 4 with
substituted benzyl zinc reagents 5a
9
10
43% yield
Entry 4, R1, R2, R3 5, Ar
Time
Product Yield (%)b
Not only benzylzinc bromides but also methylzinc iodide is
suitable reagent in this ring-opening reaction. 1,2-Dihydro-
2-methyl-1-naphthol (11) was afforded in 95% yield from
oxabicyclic alkene 4 using CH3ZnI as reagent in the pres-
ence of 0.5 mol% amount of 3 in toluene. However, only
16% yield of Et substituted dihydronaphthol 12 was pro-
vided when ethylzinc iodide was used under same condi-
tion. In addition, hydride attacked product 13 was
separated in 55% yield caused by b-H elimination reaction
(Eq. (4)) [13].
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
a
4a(H,H,H)
4a(H,H,H)
4a(H,H,H)
4a(H,H,H)
4a(H,H,H)
4a(H,H,H)
4a(H,H,H)
4a(H,H,H)
4a(H,H,H)
4b(CH3,H,H) a, Phenyl
4c(H,CH3,H) a, Phenyl
4d(H,H,CH3) a, Phenyl
4d(H,H,CH3) a, Phenyl
a, Phenyl
1 h
1 h
6aa
6ab
77
65
85
58
63
66
72
73
80
74
79
28
82c
b, 3-MeC6H4
c, 4-MeC6H4
d, 3-ClC6H4
e, 2-MeC6H4
25 min 6ac
40 min 6ad
45 min 6ae
f, 3,5-(Me)2C6H3 45 min 6af
g, 4-BrC6H4
h, 2-BrC6H4
i,4-MeOC6H4
1.5 h
2 h
30 min
30 min 6ba
45 min 6ca
8 h
30 min 6da
3 h
1.5 h
6ag
6ah
7
6da
CH3ZnI
OH
4e(H,Br,H)
4e(H,Br,H)
a, Phenyl
a, Phenyl
6ea + 8 68d
6ea
65c
palladacycle 3
(0.5 mol%)
toluene
Oxabicyclic alkene 4 (0.5 mmol), ArCH2ZnBr 5 (1 mmol) and 3
80 °C
(0.05 mol%) in toluene (2 mL).
11
O
b
Isolated yields.
0.5 mol% of 3 was used.
The products are 6ea and byproduct 8 with the ratio of 1:1 determined
95% yield
c
ð4Þ
EtZnI
OH
OH
d
palladacycle 3
4a
by 1H NMR.
(0.5 mol%)
+
toluene
80 °C
13
55% yield
12
16% yield
As showed in Table 2, all substituted benzylzinc bromides
5, in spite of different electronic property and steric
hindrance of substituents, reacted smoothly with 4a to pro-
vide corresponding products in good yields (entries 1–8),
except for 5i with methoxy group at para-position of ben-
zene ring, which afforded naphthol 7 as a sole product (en-
try 9). The presence of methyl group on phenyl ring of 4
did not influence the yield of the reaction (entries 10 and
11). However, the yield was only 28% if Me group was at
the position of oxo-bridge carbon of 4d (entry 12) while
the reaction provided the mixture of 6ea and 8 in 68% yield
with the ratio of 1:1 using bromo substituted oxabicyclic
In most case when the palladacycle served as a precatalyst,
the reaction proceeds at temperature higher than 120 ꢁC, at
which ‘‘active Pd species’’ is released [2d,2f,7b], however, in
our case the reaction run at 80 ꢁC or lower. In addition, no
visible palladium black was observed in the reaction. 31P
NMR spectrum of palladacycle 3 showed the signal at d
34.9 ppm (A of Fig. 2); when one equivalent of benzylzinc
bromide 5a was added, a new peak at d 34 ppm appeared
(B of Fig. 2); excess zinc reagent made the peak at d
34.9 ppm disappeared (C of Fig. 2), only the signal at d
34.9 ppm was found after quenching with aqueous NH4Cl

T.-K. Zhang et al. / Journal of Organometallic Chemistry 692 (2007) 1912–1919
1915
Fig. 2. 31P NMR spectrum of (a) palladacycle 3 in CDCl3; (b) palladacycle 3 with BnZnBr (1 equiv.) in CDCl3; (c) palladacycle 3 with BnZnBr (>1 equiv.)
in CDCl3; (d) mixture in c was quenched with aqueous NH4Cl. (e) after the completion of the reaction of 4a with BnZnBr catalyzed by 3 in CDCl3; (f)
mixture in e was quenched with aqueous NH4Cl.
(D of Fig. 2). Mixture of 4a with benzylzinc bromide 5a
and palladacycle 3, after the completion of the reaction,
showed also the peak at d 34 ppm from 31P NMR spectrum
(E of Fig. 2), which was shifted to d 34.9 ppm again when
the mixture was quenched with aqueous NH4Cl (F of
Fig. 2). We also found that the reaction of 4a with 5a
was catalyzed by 0.5 mol% of 14 to give 93% yield of
product 6aa. The phenomena are totally same when we
repeated the experiments above using 14. The only differ-
ence is that 31P NMR spectrum of palladacycle 14 showed
the signal at 42 ppm and that of mixture of 14 and 5a at d
35 ppm. These experimental results implied that the skele-
ton of 3 remained intact in the reaction, which means that
palladacycle 3 was a real catalyst in the reaction though the
products are racemic.
3. Conclusions
Palladacycle 3 is a highly active catalyst for the ring
opening reaction of oxabicylic alkenes with in situ pre-
pared organozinc halides, which shows a new application
of palladacycles in organic synthesis. NMR experiments
suggested that the palladacycle did not serve as a cata-
lyst precursor but a real catalyst in the process, although
it is unclear that why no asymmetric induction in the
reaction took place. Further studies on the reaction
mechanism in detail and other applications of palladacy-
cles in organic synthesis, especially in asymmetric cataly-
sis are in progress.
4. Experimental
4.1. General remarks
NMe2
All reactions were performed under an atmosphere of
either dry argon or nitrogen using oven-dried glassware.
Solvents were treated using standard procedures and were
distilled under an atmosphere of nitrogen before use.
Pd
Cl
Ph3P
14

1916
T.-K. Zhang et al. / Journal of Organometallic Chemistry 692 (2007) 1912–1919
Commercially available reagents were used without fur-
ther purification. The substrates 4a [14], 4b [16], 4c [15],
4d [17], 4e [15], 9 [18] and palladacycle 2, [12] 14, [21]
organozinc halides [11d,19] were prepared according to
1H), 5.80 (dd, J = 2.5 Hz, 9.6 Hz, 1H), 6.57 (dd,
J = 2.4 Hz, 9.6 Hz, 1H), 7.12–7.25 (m, 3H), 7.26–7.37 (m,
6H); MS (EI) m/z (rel) 236 (M+, 1), 145 (100.00), 218
(53.94), 91 (44.59), 127 (38.66), 115 (29.24), 128 (22.62),
116 (15.95).
1
reported procedures. H NMR spectra were recorded in
CDCl3 and the chemical shifts were referenced to CHCl3
(d 7.27) and that of 13C NMR and 31P NMR spectra
were referenced to CHCl3 (d 77.00) and to external
85% H3PO4 respectively. IR spectra were measured in
4.5. 2-(30-Methylbenzyl)-1,2-dihydronaphthalen-1-ol (6ab)
White solid, m.p. 67–68 ꢁC. 1H NMR (300 MHz,
CDCl3): d 2.35 (s, 3H), 2.78–2.90 (m, 2H), 3.08–3.18 (m,
1H), 4.50 (d, J = 2.1 Hz, 1H), 5.82 (d, J = 10.2 Hz, 1H),
6.57 (dd, J = 2.7 Hz, 9.3 Hz, 1H), 7.05–7.16 (m, 4H),
7.20–7.32 (m, 4H); 13C NMR (75 MHz, CDCl3): d
139.99, 137.96, 136.50, 132.57, 130.36, 130.04, 128.59,
128.28, 127.68, 127.63, 127.04, 126.87, 126.56, 126.27,
69.66, 42.48, 35.26, 21.43; MS (EI) m/z (rel) 232
(M+ꢁH2O), 145 (100.00), 127 (61.76), 232 (59.55), 128
(37.64), 115 (35.40), 117 (34.22), 144 (32.49), 105 (28.13);
IR (KBr): 3389, 3325 cmꢁ1; HRMS (M+ꢁH2O) for
C17H16: 232.1252; Found: 232.12606.
cmꢁ1
.
4.2. Synthesis of palladacycle 3
To a solution of palladacycle 2 (168 mg, 0.2 mmol) in
CH2Cl2 (10 mL) was added PPh3 (118 mg, 0.45 mmol) at
room temperature and the resulting mixture was stirred
for 5 min. The solvent was removed in vacuum, and the
crude product was purified by flash chromatography
(AcOEt/petroleum ether = 1/5) to give palladacycle 3 as
20
a white solid (266 mg, 98%): m.p. > 300ꢁC; ½aꢂD ¼ ꢁ18:8ꢃ
(c = 0.68, CHCl3). 1H NMR: 0.57 (d, J = 6.6 Hz, 3H),
0.80 (d, J = 6.6 Hz, 3H), 1.62 (s, 3H), 2.05–2.15 (m, 1H),
2.40 (s, 3H), 4.27 (dd, J = 5.7 Hz, 8.7 Hz, 1H), 4.46 (dd,
J = 8.7 Hz, 9.9 Hz, 1H), 5.10–5.18 (m, 1H), 6.18–6.24 (m,
1H), 6.64–6.78 (m, 2H), 6.88–6.94 (m, 1H), 7.25–7.40 (m,
9H), d 7.52–7.61 (m, 6H); 13C NMR: d 176.98, 153.52,
153.47, 144.91, 139.39, 139.28, 135.31, 135.17, 132.27,
131.62, 130.31, 130.28, 128.22, 128.07, 125.48, 125.41,
122.85, 122.77, 72.09, 68.42, 44.21, 34.90, 31.32, 23.45,
18.23, 16.22. 31P NMR: d 34.9 (s). MS (EI) m/z 598
(M+ꢁBr), 230 (100.00), 262 (46.07), 183 (36.96), 231
(18.16), 108 (14.04), 261 (13.19), 263 (9.59), 107 (9.13);
IR (KBr, cmꢁ1): 2963, 1637, 1436, 1096, 695 cmꢁ1; Anal.
Calcd. for C15H20BrNOPd: C, 58.38; H, 5.20; N, 2.06.
Found: C, 58.40; H, 5.24; N, 1.90%.
4.6. 2-(40-Methylbenzyl)-1,2-dihydronaphthalen-1-ol (6ac)
[11d]
Yellow oil. 1H NMR (300 MHz, CDCl3): d 2.35 (s, 3H),
2.74–2.81 (m, 1H), 2.85 (dd, J = 8.0 Hz, 12.8 Hz, 1H), 3.11
(dd, J = 8.0 Hz, 12.8 Hz, 1H), 4.47 (d, J = 3.6 Hz, 1H),
5.80 (dd, J = 2.6 Hz, 9.3 Hz, 1H), 6.56 (dd, J = 2.5 Hz,
9.3 Hz, 1H), 7.12–7.25 (m, 6H), 7.28–7.43 (m, 2H); MS
(EI) m/z (rel) 250 (M+, 1), 145 (100.00), 232 (91.87), 128
(70.84), 105 (57.41), 127 (47.35), 144 (43.09), 217 (36.95),
115 (24.29).
4.7. 2-(30-Chlorobenzyl)-1,2-dihydronaphthalen-1-ol (6ad)
1
Yellow oil. H NMR (300 MHz, CDCl3): d 2.64–2.82
4.3. General procedure for the reaction of oxabicyclic
alkenes 4 with organozinc halides 5 in the presence of
palladacycle 3
(m, 2H), 2.95–3.14 (m, 1H), 4.44 (d, J = 3.0 Hz, 1H),
5.72–5.76 (m, 1H), 6.54 (dd, J = 2.4 Hz, 9.6 Hz), 7.10–
7.30 (m, 8H); 13C NMR (75 MHz, CDCl3): d 142.24,
136.30, 134.15, 132.47, 129.80, 129.63, 129.34, 128.69,
127.78, 127.63, 127.54, 127.34, 126.64, 126.375, 69.41,
42.33, 35.02; MS (EI) m/z (rel) 252 (M+ꢁH2O), 145
(100), 115 (46.63), 127 (45.09), 144 (36.43), 252 (28.17),
117 (24.17), 116 (19.39), 89 (14.97); IR (KBr): 3556,
3385 cmꢁ1; HRMS (M+ꢁH2O) for C17H13Cl: 252.0706;
Found: 252.07043.
To a stirred solution of oxabicyclic alkenes 4 (0.5 mmol)
in toluene (2 mL) was added organozinc halides (1.5 mmol
in THF) and the appropriate amount of catalyst, obtained
by successive dilution of an initial catalyst solution. The
resulting mixture was stirred at 80 ꢁC and monitored by
TLC. After cooling, water (5 mL) was added and stirred
for 15 min. The mixture was extracted with CH2Cl2
(5 mL · 3). The combined organic phase was dried over
MgSO4, filtered, and concentrated in vacuum. The crude
product was purified by flash chromatography (ethyl ace-
tate/petroleum ether).
4.8. 2-(20-Methylbenzyl)-1,2-dihydronaphthalen-1-ol (6ae)
[11d]
1
Oil. H NMR (300 MHz, CDCl3): d 2.35 (s, 3H), 2.77–
2.81 (m, 1H), 2.89 (dd, J = 8.1, 13.2 Hz, 1H), 3.13 (dd,
J = 8.1, 13.5 Hz, 1H), 4.48 (s, 1H), 5.79–5.89 (m, 1H),
6.56 (dd, J = 2.1, 9.3 Hz, 1H), 7.12–7.30 (m, 8H); MS
(EI) m/z (rel) 250 (M+, 1), 232 (44.33), 145 (100.00), 127
(65.64), 115 (45.39), 105 (43.84), 77 (34.66), 65 (12.45),
51(17.25), 39 (20.33).
4.4. 2-Benzyl-1,2-dihydro-naphthalen-1-ol (6aa) [9k]
Yellow oil. 1H NMR (300 MHz, CDCl3): d 1.62 (s, 1H),
2.77–2.81 (m, 1H), 2.89 (dd, J = 8.0 Hz, 12.8 Hz, 1H), 3.15
(dd, J = 7.7 Hz, 12.8 Hz, 1H), 4.47 (dd, J = 4.1 Hz, 7.0 Hz,

T.-K. Zhang et al. / Journal of Organometallic Chemistry 692 (2007) 1912–1919
1917
4.9. 2-(30,50-Dimethylbenzyl)-1,2-dihydronaphthalen-1-ol
(6af)
4.13. 2-Benzyl-6,7-dimethyl-1,2-dihydronaphthalen-1-ol
(6ca)
White solid, m.p. 107–109 ꢁC. 1H NMR (300 MHz,
White solid, m.p. 101–103 ꢁC. 1H NMR (300 MHz,
CDCl3): d 1.55 (d, J = 4.5 Hz, 1H),2.23 (s, 6H), 2.70–2.80
(m, 1H), 2.88 (dd, J = 8.1Hz, 6.6 Hz, 1H), 3.15 (dd,
J = 8.1 Hz, 12.9 Hz, 1H), 4.38 (dd, J = 4.5 Hz, 8.2 Hz,
1H), 5.71 (d, J = 9.0 Hz, 1H), 6.50 (dd, J = 3.0 Hz,
9.9 Hz, 1H), 6.92 (s,1H), 7.04 (s,1H), 7.20–7.24 (m, 1H),
7.28–7.36 (m, 4H); 13C NMR (75 MHz, CDCl3): d
140.16, 136.77, 136.00, 134.02, 130.13, 129.22, 129.10,
129.08, 128.31, 127.87, 126.89, 126.00, 69.30, 42.70,
35.51, 19.50, 19.44; MS (EI) m/z 264 (M+), 173 (100),
158 (37.94), 172 (26.84), 91 (18.13), 145 (16.69), 174
(13.53), 155 (11.89), 128 (10.82); IR (KBr): 3372,
3034 cmꢁ1; Anal. Calcd. for C19H20O: C, 86.32; H, 7.63;
Found: C, 86.14; H, 7.48%.
CDCl3): 2.34 (m, 6H), 2.78–2.87 (m, 2H), 3.04–3.14 (m,
1H), 4.50 (dd, J = 3.3 Hz, 6.9 Hz, 1H), 5.83 (d, J =
9.9 Hz, 1H), 6.57 (dd, J = 2.7 Hz, 9.9 Hz, 1H), 6.88–6.96
(m, 3H), 7.12–7.18 (m, 1H), 7.22–7.34 (m, 3H); 13C
NMR (75 MHz, CDCl3):
d 140.02, 137.87, 136.58,
132.65, 130.54, 128.58, 127.79, 127.70, 127.63, 127.09,
127.02, 126.56, 6 9.75, 42.506, 35.18, 21.33; MS (EI) m/z
(rel) 364 (M+), 145 (100.00), 127 (54.80), 246 (48.35), 128
(35.84), 115 (33.54), 117 (32.00), 119 (26.83), 144 (23.64);
IR (KBr): 3365, 3290 cmꢁ1; HRMS (M+ꢁH2O) for
C19H18: 246.1409; Found: 246.14119.
4.10. 2-(40-Bromobenzyl)-1,2-dihydronaphthalen-1-ol (6ag)
[11d]
4.14. 2-Benzyl-1,4-dimethyl-1,2-dihydronaphthalen-1-ol
(6da)
White solid. 1H NMR (300 MHz, CDCl3): 2.72–2.78 (m,
1H), 2.83 (dd, J = 7.8 Hz, 13.0 Hz, 1H), 3.10 (dd,
J = 8.4 Hz, 12.8 Hz, 1H), 4.42 (d, J = 3.3 Hz, 1H), 5.75
(dd, J = 2.4 Hz, 9.5 Hz, 1H), 6.57 (dd, J = 2.5 Hz,
9.5 Hz, 1H), 7.11–7.32 (m, 6H), 7.39–7.46 (m, 2H); MS
(EI) m/z (rel) 314 (M+, 1), 145 (100.00), 127 (29.71), 128
(19.31), 115 (18.39), 117 (14.49), 144 (12.66), 146 (11.35),
90 (8.35).
Yellow oil. 1H NMR (300 MHz, CDCl3): d 1.55 (s,
3H), 2.04 (s, 3H), 1.95 (br, 1H), 2.38 (dd, J = 10.5 Hz,
23.1 Hz, 1H), 2.50–2.62 (m, 1H), 3.13 (dd, J = 5.2 Hz,
12.6 Hz, 1H), 5.59 (dd, J = 1.5 Hz, 5.7 Hz, 1H), 7.12–
7.16 (m, 2H), 7.20–7.23 (m, 1H), 7.28–7.38 (m, 5H),
7.60–7.66 (m, 1H); 13C NMR (75 MHz, CDCl3): d
141.46, 140.60, 133.72, 130.53, 129.19, 128.32, 128.09,
127.78, 127.18, 125.74, 123.40, 123.26, 74.40, 47.66,
34.81, 28.88, 19.07; MS (EI) m/z 264 (M+), 173
(100.00), 158 (31.65), 91 (19.78), 145 (18.04), 174
(13.79), 128 (11.27), 129 (10.10), 115 (9.80); IR (KBr):
4.11. 2-(20-Bromobenzyl)-1,2-dihydronaphthalen-1-ol (6ah)
[9k]
3464, 3062 cmꢁ1; HRMS (M+ + Na) for C19H20ONa+1
287.1420; Found: 287.14064.
:
1
Oil. H NMR (300 MHz, CDCl3): d 2.29–2.99 (m, 2H),
3.03 (dd, J = 7.5, 12.9 Hz, 1H), 3.11–3.3–21 (dd, J = 8.1,
12.9 Hz, 1H), 4.44–4.98 (m, 1H), 5.78–5.83 (m, 1H),
6.57 (dd, J = 2.1, 9.3 Hz, 1H), 7.08–7.58 (m, 8H); MS
(EI) m/z 314 (M+), 145 (100.00), 127 (52.85), 144
(28.47), 115 (25.58), 77 (25.41), 117 (22.94), 79 (18.59),
128 (15.99).
4.15. 2-Benzyl-6,7-dibromo-1,2-dihydronaphthalen-1-ol
(6ea)
White solid, m.p. 117–118 ꢁC. 1H NMR (300 MHz,
CDCl3): d 2.70–2.85 (m, 2H), 3.10 (dd, J = 6.6 Hz,
11.7 Hz, 1H), 4.47–4.52 (m, 1H), 5.90 (dd, J = 2.7 Hz,
9.9 Hz, 1H), 6.46 (d, J = 9.9 Hz, 1H), 7.24–7.35 (m,
5H), 7.38 (m, 1H), 7.56 (m, 1H); 13C NMR (75 MHz,
CDCl3): d 139.49, 137.03, 133.25, 132.46, 132.33, 131.09,
129.17, 128.48, 126.31, 125.26, 124.34, 122.90, 68.69,
42.22, 34.72; MS (EI) m/z 376 (M+ꢁH2O), 224 (100.00),
222 (94.21), 91 (90.97), 115 (59.29), 376 (38.26), 286
4.12. 2-Benzyl-5,8-dimethyl-1,2-dihydronaphthalen-1-ol
(6ba)
Oil. 1H NMR (300 MHz, CDCl3): d 1.57 (d, J = 7.5 Hz,
1H), 2.34 (s, 6H), 2.70–2.80 (m, 1H), 3.01 (dd, J = 8.1 Hz,
13.5 Hz, 1H), 3.21 (dd, J = 8.4 Hz, 13.5 Hz,1H), 4.67 (dd,
J = 4.8 Hz, 7.8 Hz 1H), 5.83 (m, 1H), 6.78 (dd,
J = 2.7 Hz, 9.6 Hz, 1H), 7.05 (dd, J = 8.4 Hz, 16.5 Hz,
2H), 7.22–7.30 (m, 1H), 7.38 (d, J = 5.1 Hz, 4H); 13C
(32.21), 65 (31.48), 303 (27.58). IR (KBr): 3306 cmꢁ1
;
Anal. Calcd. for C17H14Br2O: C, 51.81; H, 3.58; Found:
C, 52.08; H, 3.64.
NMR (75 MHz, CDCl3):
d 140.39, 134.73, 133.63,
131.91, 130.69, 130.29, 129.87, 129.53, 129.42, 128.70,
126.39, 124.68, 65.89, 42.39, 36.18, 19.24, 18.52; MS (EI)
m/z 264 (M+), 173 (100.00), 158 (36.87), 91 (21.74), 145
(19.86), 172 (19.25), 174 (13.50), 155 (13.37). IR (KBr):
4.16. 6-Benzyl-2,3-dimethyl ester-2,4-dienol (10)
White solid, m.p. 86–88 ꢁC. 1H NMR (300 MHz,
CDCl3): d 2.59–2.71 (m, 1H), 3.14 (d, J = 13.8 Hz, 1H),
3.41 (d, J = 13.8 Hz, 1H), 3.49 (m, 3H), 3.74 (m, 3H),
5.18–5.24 (m, 1H), 5.58–5.64 (m, 1H), 5.81–5.86 (m, 1H),
3557, 3436 cmꢁ1; HRMS (M+ + Na) for C21H19ONa+1
287.1416; Found: 287.14304.
:

1918
T.-K. Zhang et al. / Journal of Organometallic Chemistry 692 (2007) 1912–1919
7.01–7.05 (m, 1H), 7.10–7.15 (m, 3H), 7.17–7.24 (m, 2H);
13C NMR (75 MHz, CDCl3): d 176.24, 166.34, 137.91,
134.21, 131.22, 129.20, 127.10, 126.10, 121.24, 74.50,
56.35, 52.55, 51.71, 31.74; MS (EI) m/z 270 (M+ꢁOCH3),
91 (100.00), 179 (44.12), 163 (36.83), 65 (31.65), 270
(31.00), 77 (20.18), 59 (19.36), 210 (18.10); IR (KBr):
3487, 1745, 1716, 1269 cmꢁ1; Anal. Calcd. for C17H18O5:
C, 67.54; H, 6.00; Found: C, 67.17; H, 6.12%.
Acknowledgments
Financially supported by National Natural Sciences
Foundation of China, Chinese Academy of Science, Crou-
cher Foundation of Hong Kong and Shanghai Committee
of Science and Technology. T.K.Z. gratefully thanks the
Croucher Foundation of Hong Kong for a studentship.
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