Iridium-catalyzed asymmetric ring-opening of oxabicyclic alkenes with carboxylic acids

Article abstract of DOI:10.1007/s10562-013-1136-x

A novel iridium-catalyzed asymmetric ringopening of oxabicyclic alkenes with a variety of carboxylic acids was reported, which afforded the corresponding trans-carboxylic acids 1-hydroxy-1,2-dihydro-naphthalen-2-yl ester products in good yields with moderate enantioselectivities under mild conditions. The trans products are formed via the enantioselective cleavage of a bridgehead carbon-oxygen bond in 1 followed by S_N2' nucleophilic attack by carboxylic acids. The effects of various bisphosphine ligands, Ag(I) salts, ammonium halides, bases, and solvents on the yields and enantioselectivities of the reaction were also investigated. The theoretical analysis of stability and hydrogen bond for 1-hydroxy-1,2-dihydronaphthalen-2-yl 4-chlorobenzoate 2a were performed using the density functional theory B3LYP methods. The trans-configuration of the product 2a was confirmed by X-ray diffraction analysis. A possible mechanism for the present catalytic reaction was proposed. Springer Science+Business Media New York 2013.

Full text of DOI:10.1007/s10562-013-1136-x

Catal Lett (2014) 144:419–433
DOI 10.1007/s10562-013-1136-x
Iridium-Catalyzed Asymmetric Ring-Opening of Oxabicyclic
Alkenes with Carboxylic Acids
•
Yuhua Long Xiaolu Li Xuejing Pan
•
•
•
Dandan Ding Xuan Xu Xiongjun Zuo
•
•
•
Dingqiao Yang Sanyong Wang Chunrong Li
•
Received: 8 September 2013 / Accepted: 6 October 2013 / Published online: 6 November 2013
Ó Springer Science+Business Media New York 2013
Abstract A novel iridium-catalyzed asymmetric ring-
opening of oxabicyclic alkenes with a variety of carboxylic
acids was reported, which afforded the corresponding
trans-carboxylic acids 1-hydroxy-1,2-dihydro-naphthalen-
2-yl ester products in good yields with moderate enanti-
oselectivities under mild conditions. The trans products are
formed via the enantioselective cleavage of a bridgehead
carbon–oxygen bond in 1 followed by SN20 nucleophilic
attack by carboxylic acids. The effects of various bis-
phosphine ligands, Ag(I) salts, ammonium halides, bases,
and solvents on the yields and enantioselectivities of the
reaction were also investigated. The theoretical analysis of
stability and hydrogen bond for 1-hydroxy-1,2-di-
hydronaphthalen-2-yl 4-chlorobenzoate 2a were performed
using the density functional theory B3LYP methods. The
trans-configuration of the product 2a was confirmed by
X-ray diffraction analysis. A possible mechanism for the
present catalytic reaction was proposed.
1 Introduction
Asymmetric ring-opening (ARO) is one of the most
important methods of great utility in organic synthesis.
Recently, this area has been paid increasing attention and
extensively investigated [1]. Many parameters have been
examined for these reactions, including a variety of metal
catalysts such as Fe[2], Ni [3–6], Cu [7–10], Ru [11–17],
Rh [18–27], Pd [28–41], etc., and nucleophiles such as
alcohols [42], phenols [43], thiophenols [44], amines [45],
Grignard reagents [46–49], organozinc reagents [50],
organoboronic acids [51, 52], organozinc halides, alkynes
[53], and others [54, 55]. Iridium-catalyzed allylic substi-
tution is an efficient protocol for the construction of both
carbon–carbon bonds and carbon–heteroatom bonds, which
provides a feasible way to generate useful multifunctional
chiral building blocks [56–64].
Our group has demonstrated that iridium-catalyzed ARO
of strained bicyclic alkenes is a highly efficient and enantio-
selective process for generating a functionalized dihydro-
naphthalene core. Chiral iridium(I) complexes catalyze the
ring-opening reaction of oxa- and azabicyclic alkenes with a
variety of nucleophiles such as amines, alcohols and phenols
in high yield and enantioselectivity [65–72]. The products are
generated by an SN20 nucleophilic displacement of the
bridgehead leaving group with inversion to give the 1,2-trans
product. To expand the scope of this novel Ir-catalyzed
reaction, we are interested in studying the ARO of oxabicyclic
alkenes with oxygen-based nucleophiles in the presence of
iridium catalysis. ARO of oxabicyclic alkenes is a valuable
synthetic methodology to create highly functionalized ring
systems. These methods offer potentially useful routes to the
synthesis of enantioenriched trans-1,2-dihydronaphthalenes
products which are the scaffolds for total synthesis of bioac-
tive compounds [73].
Keywords Iridium catalysis ꢀ Asymmetric ring-
opening ꢀ Oxabicyclic alkenes ꢀ Chiral bisphosphine
ligand
Y. Long ꢀ X. Li ꢀ X. Pan ꢀ D. Ding ꢀ X. Xu ꢀ X. Zuo ꢀ
D. Yang (&)
Key Laboratory of Theoretical Chemistry of Environment,
Ministry of Education, School of Chemistry and Environment,
South China Normal University, Guangzhou 510006,
People’s Republic of China
e-mail: yangdq@scnu.edu.cn
S. Wang ꢀ C. Li
Guangdong Food Industry Institute, Guangzhou 510308,
People’s Republic of China
123

420
Y. Long et al.
To the best of our knowledge, there has been no
unfortunately, we did not obtain the desired the ring-
opening product 2a. When silver(I) triflate (AgOTf) and
ammonium halides as additives were employed in the
presence of iridium complex [Ir(COD)Cl]2, the silver
chloride (AgCl) was first precipitated by the addition of
AgOTf and followed by the addition of the (S)-p-Tol-
BINAP ligand and then the addition of tetrabutylammo-
nium iodide (Bu4NI). In this way, by a halide exchanging
protocol, cationic iridium complexes [Ir((S)-p-Tol-BIN-
AP)I]2 are formed. Under these conditions, the desired the
ring-opening product 2a was obtained. The results showed
that the addition of a base in conjunction with halide effect
together promoted to a more rapid conversion of 1a.
Based on our previous studies, we investigated the effect
of ammonium halides as additives on the ring opening
reaction (Table 2, entries 1–5). Employed by NH4Cl/Et3N,
NH4F/Et3N or NH4Br/Et3N as additives, unfortunately, the
ring-opening did not occur. In the presence of NH4I
and Et3N, the reaction proceeded smoothly and obtained
the corresponding product in 70 % yield, but with lower
enantioselectivity (18 % ee). If the reaction was in the
presence of 2 equiv of Bu4NI and 5 equiv of triethylamine,
we obtained the corresponding product 2a in 62 % yield
with 70 % ee (Table 2, entry 5). While the molar ratio of
Bu4NI to 1a changed to 1:1 or 3:1, the reaction gave a
lower enationselectivity (Table 1, entries 6 and 7). To
promote the ability of nucleophile reagent, several bases
were added to the reaction mixture, but the results
example of using carboxylic acids as the nucleophile in
iridium-catalyzed reactions, particularly in ARO for oxa-
bicyclic alkenes. The stereochemical outcome (trans/cis) of
the ring-opening product is unknown. Herein, we report
that iridium-catalyzed the ARO of oxabenzonorbornadiene
with various carboxylic acids afford the corresponding
trans-carboxylic acids 1-hydroxy-1,2-dihydro-naphthalen-
2-yl ester in moderate yields with enantioselectivities under
relatively mild conditions. The effects of various bisphos-
phine ligands, Ag(I) salts, ammonium halides, bases, and
solvents on the yields and enantioselectivities of the reac-
tion were also investigated. All geometry optimizations and
frequency calculations on cis and trans isomers of
1-hydroxy-1,2-dihydronaphthalen-2-yl 4-chlorobenzoate
2a were performed using the density functional theory
B3LYP methods [74, 75].
2 Results and Discussion
The oxabenzonorbornadienes 1a–1e were prepared
according to the literature procedures [76, 77]. An achiral
ligand 1,10-bis(diphenylphosphino)ferrocene (DPPF) was
also first chosen to validate the catalytic activity of the
iridium complex in the ring-opening reactions of oxa-
benzonorbornadiene 1a with p-chlorobenzoic acid in tet-
rahydropyran (THP) at 80 °C (not shown in Table 1),
Table 1 Screen for the iridium-catalyzed ARO of oxabenzonorbornadiene 1a with p-chlorobenzoic acid
Entry
Additive
Time (h)
Yield (%)
eea (%)
1
NH4F/Et3N
NH4Cl/Et3N
NH4Br/Et3N
NH4I/Et3N
36
36
36
24
20
20
20
22
23
nr
–
2
nr
–
3
Trace
70
–
4
18
70
16
58
54
52
5
Bu4NI/Et3N
Bu4NI/Et3N
Bu4NI/Et3N
Bu4NI/PMP
Bu4NI/TMEDA
62
6b
7c
8
55
63
52
9
48
Conditions: [Ir(COD)Cl]2 (2.5 mol%), ligand (5.0 mol%) added to flask and followed by adding AgOTf (5 mol%) then Bu4NI (5 mol%). To this
was added 1a and followed by heating to reflux in THP. At first sign of reflux, R4NX (2 equiv) was added and followed by the p-chlorobenzoic
acid (5 equiv) and Et3N (5 equiv)
a
Determined by HPLC with a Chiralcel OD-H column
b
Bu4NI (1 equiv) was added as additive
c
Bu4NI (3 equiv) was added as additive
123

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabicyclic Alkenes
421
were unsatisfactory. The yield and enantioselectivity
results showed that organic base N,N,N0,N0-tetra-
methylethylenediamine (TMEDA) and 1,2,2,6,6-pentame-
thylpiperidine (PMP) were both no better than
triethylamine and no reaction occurred when the inorganic
base Na2CO3 or Cs2CO3 was used. Among the bases tested,
it revealed that Et3N as an additive was more beneficial to
the ARO. These results showed that Bu4NI and Et3N as
additives were highly effective for promoting the ring
opening of 2a. The best result, therefore, was obtained
when 2 equiv of Bu4NI, 5 equiv of triethylamine and car-
boxylic acid were added to the reaction mixture (62 %
yield, 70 % ee) (Table 2, entry 5).
only (S)-p-Tol-BINAP offered better results (Table 2, entry
6). Other ligands such as (R)-(S)-PPF-PtBu2, (S)-Segphos,
(S)-Xyl-BINAP and (S)-BINAP gave unsatisfactory results
(Table 2, entries 2–5). Therefore, we decided to choose
(S)-p-Tol-BINAP as a ligand for the reaction. Then we
investigated the impact of catalyst loading on yields and
enantioselectivities (Table 2, entries 6–9). It was further
found that 2.5 mol% of [Ir(COD)Cl]2 and 5 mol% of (S)-p-
Tol-BINAP would be more suitable the amount of catalyst
loading in terms of the product yield and ee value. Slightly
higher yields but lower enantioselectivities were observed
when more amount of catalyst was loaded (Table 2, entry
9), and lower catalyst loading (1.5 mol%) resulted to get
lower ee value (Table 2, entry 7).
To asymmetric ring-opening, the choice of ligand was
very important; we then ran the asymmetric version of the
same reaction using different kinds of chiral bisphosphine
ligands. Among these chiral ligands has tested, we found
To obtain better yields and higher enantioselectivities, a
number of parameters including solvents and temperature
have therefore been investigated. Solvent effect study
Table 2 Effects of chrial ligand and catalyst loading
Entry
Ligand (mol%)
[Ir(COD)Cl]2 (mol%)
Time (h)
Yield (%)
eea (%)
1
2
3
4
5
6
7
8
9
a
5.0 DPPF
2.5
2.5
2.5
2.5
2.5
2.5
1.5
2.0
3.0
40
30
48
24
40
18
19
19
19
35
53
48
55
62
62
65
57
50
0
5.0 (S)-BINAP
5.0 (R)-(S)-PPF-PtBu2
18
42
23
39
70
30
35
36
5.0 (S)-Segphos
5.0 (S)-Xyl-BINAP
5.0 (S)-p-Tol-BINAP
3.0 (S)-p-Tol-BINAP
4.0 (S)-p-Tol-BINAP
6.0 (S)-p-Tol-BINAP
The reaction was carried out with 1a (0.2 mmol) and p-chlorobenzoic acid (1 mmol) in the presence of halide additive Bu4NI (0.4 mmol) and
Et3N (1.0 mmol) in THP at 80 °C (oil bath temperature), and the mole ratio of [Ir(COD)Cl]2/(S)-p-Tol-BINAP/AgOTf/Bu4NI = 1:2:2:2
b
Determined by HPLC with a Chiralcel OD-H column
123

422
Y. Long et al.
Table 3 Optimization of the solvent and temperature
Entry
Solvent
Tempa(°C)
Time (h)
Yield (%)
eeb (%)
1
THFc
THF
80
100
25
80
100
80
80
80
80
80
80
40
24
48
18
15
22
24
24
19
25
36
53
54
33
–
2
70
3
THP
nr
4
THP
62
70
43
47
–
5
THP
68
6
Toluene
CH2Cl2
DCE
48
7
trace
trace
50
8
–
9
dioxane
DME
CH3CN
50
41
–
10
11
55
nr
Conditions: [Ir(COD)Cl]2 (2.5 mol%), ligand (5.0 mol%) added to flask and followed by adding AgOTf (5 mol%) then Bu4NI (5 mol%). To this
mixture was added 1a and followed by heating to reflux in THP. At first sign of reflux, Bu4NI (2 equiv) was added and followed by the
p-chlorobenzoic acid (5 equiv) and Et3N (5 equiv)
a
Oil bath temperature
b
Determined by HPLC with a Chiralcel OD-H column
c
THF is tetrahydrofuran
showed that THP was the best one among the solvents
tested. Temperature also played a crucial role in the ring
opening reaction. At room temperature, there was no
reaction (Table 3, entry 3). By increasing the oil bath
temperature to 80 °C and running the reaction in THP, the
yield of 2a was increased to 62 % with 70 % ee (Table 3,
entry 4). At higher temperature such as 100 °C, it was
found that the reaction gave a better yield with low
enantioselectivity (Table 3, entry 5). Therefore, optimal
reaction temperature was identified as 80 °C in THP giving
the desired product 2a in moderate yield with moderate
enantioselectivity.
benzoic acid (Table 4, entries 1–11 and 13), meta-substi-
tuted benzoic acid were found to give better yields than
that of ortho- and para-substituted benzoic acid. It was
further found that para-substituted benzoic acid gave
higher ee than that of ortho- and meta-substituted. On the
other hand, the reaction afforded better yield and enanti-
oselectivity when 1a reacted with substituted carboxylic
acid bearing electron-withdrawing groups than those with
electron-donating groups. For instance, nucleophile such
as p-chlorobenzoic acid gave higher enantioselectivity than
p-methylbenzoic acid and p-methoxybenzoic acid
(Table 4, entries 1, 8 and 9).
On the basis of these studies, the ARO of 1a with a
variety of carboxylic acid was explored under the optimal
reaction conditions: 2.5 mol% of [Ir(COD)Cl]2 and
5 mol% of (S)-p-Tol-BINAP, 5 mol% AgOTf, 5 mol%
Bu4NI, Bu4NI/Et3N as additives and 5.0 equiv of nucleo-
phile in THP at 80 °C. When aliphatic carboxylic acids as
uncleophiles were employed, we found that the reaction
gave the corresponding products 2o in moderate yield with
low ee value (Table 4, entry 15). Using aromatic carbox-
ylic acids as nucleophiles, the corresponding product 2a–
2n was obtained in moderate yields but with good enanti-
oselectivities. As is shown in Table 4, the position of the
substituent on the benzene ring had a significant impact on
both yields and enantioselectivities. Among substituted
To further investigate the scope of this reaction to sub-
strate, ring-opening reactions of several substituted oxa-
benzonorbornadienes 1b–1e with carboxylic acids were
studied as shown in Table 5. The results were shown that the
nature of the substituent group in the oxabicyclic alkene
plays a significant role in the enantioselectivity of the reac-
tion. The substrate 1b containing methoxy groups on the 5-
and 8-positions, reacted with various substituted carboxylic
acids to form ring-opening products 3a–3e in moderate
yields with lower enantioselectivties (Table 5, entries 1–5).
No ring-opening product of substrates 1c, 1d, and 1e was
observed when halogen-substituted benzoic acid was used
(Table 5, entries 6–9). However, the substrate 1d gave
product 5aa in yield (90 %) because of elimination reaction.
123

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabicyclic Alkenes
423
functional theory B3LYP methods, Gaussian 03 package.
The 6-31G* basis sets were used for C, H and O atoms,
while 6-311G* basis sets were used for Cl atoms. The
optimized geometries were confirmed to be ground state
with frequency calculations that had no negative frequen-
cies. The natural bond orbital (NBO) were used to analyses
the hydrogen bonds involved in all the systems.
Table 4 Scope of ARO reactions of oxabenzonorbornadiene 1a with
various substituted carboxylic acids
O
[Ir(COD)Cl]2 (2.5 mol%)
O
(S)-p-Tol-BINAP (5 mol%)
RCOOH
+
O
R
AgOTf, Bu4NI, Et3N
THP, 80 oC
OH
2a-2o
1a
Entry
1
RCOOH
Product Time (h) Yield (%) eea(%)
2.1.1 Cis and Trans Isomers of 1-Hydroxy-1,2-
dihydronaphthalen-2-yl 4-chlorobenzoate (2a)
COOH
2a
2b
18
24
62
79
70
45
Cl
Cl
COOH
Figure 1 shows the structures of the two isomers. Some
selected bond lengths are listed in Table 6. There are
hydrogen bonds in two isomers. The distances of H28–O9
and H31–O10 in cis-configuration are 0.2063 nm and
0.1737 nm, respectively, indicating that there are two
hydrogen bonds, C11–H28ꢀꢀꢀO9 and O13–H31ꢀꢀꢀO10, in it.
However, the distances of H28–O9 and H31–O10 are
0.2058 and 0.2594 nm in trans-configuration, respectively.
Because the C11–O10 and C12–O13 bonds are located on
opposite of the benzene ring, the distance of H31–O10 is
very long. It results that only one hydrogen bond C11–
H28ꢀꢀꢀO9 can be formed in trans-configuration. Appar-
ently, there are two hydrogen bonds in cis-configuration
but only one in trans-configuration. Therefore, it can be
seen from Table 7, the molecular energy of the cis-con-
figuration is 1.24 kcal/mol (0.00200 a.u.) lower than trans-
configuration. Moreover, the HOMO–LUMO gap (Eg) in
the cis-configuration is 2.93 kcal/mol larger than that in the
trans-configuration. The lower molecular energy and larger
HOMO–LUMO gap all indicate the cis-configuration is
more stable than the trans-configuration.
2
3
Cl
COOH
COOH
COOH
2c
30
65
60
4
5
2d
2e
24
18
65
58
57
55
r
B
Cl
COOH
6
7
2f
30
22
61
70
61
30
Cl
CH3
COOH
2g
COOH
COOH
8
9
2h
2i
22
24
22
80
60
64
21
34
44
H3
C
H3CO
COOH
10
2j
F
3C
COOH
11
12
13
2k
2l
22
24
24
62
68
66
33
46
35
F
O
COOH
2.2 NBO Analysis
H3CO
COOH
2m
For better understanding the different contribution of each
hydrogen bond to the stability of the isomers, the NBO
analyses have been performed to reveal the nature of the
interaction. The second order perturbation stabilization
energy E(2) is listed in Table 8. The E(2) can be calculated
by Eq. (1), for a general donor NBO (i) and an acceptor
NBO (j):
COOH
14
15
2n
2o
24
28
63
75
43
25
COOH
Conditions: [Ir(COD)Cl]2 (2.5 mol%), (S)-p-Tol-BINAP(5.0 mol%),
AgOTf (5 mol%), Bu4NI (5 mol%), halide additive Bu4NI
(0.4 mmol), Et3N (1 mmol), and substituted carboxylic acid (1 mmol)
reacted with 1a (0.2 mmol) in THP (2.0 mL) at 80 °C (oil bath
temperature)
2
Fði; jÞ
Eð2Þ ¼ Eij ¼ qi
ð1Þ
ej ꢁ ei
a
Determined by HPLC with a Chiralcel OD-H or AD-H column
where qi is the donor orbital occupancy, ei and ej are
diagonal elements (orbital energies), and Fði; jÞ is the off-
diagonal element in NBO Fock matrix. The E(2) has been
proved efficient in illustrating the charge-transfer of
hydrogen bond. The larger E(2) means the stronger
hydrogen bond. As seen from Table 8, there is a C11–
H28ꢀꢀꢀO9 weak hydrogen bond resulted from the
2.1 Computational Method
All geometry optimizations and frequency calculations on
cis and trans isomers of 1-hydroxy-1,2-dihydronaphthalen-
2-yl 4-chlorobenzoate 2a were performed using the density
123

424
Y. Long et al.
Table 5 Scope of oxabicyclic alkenes
R2
O
R2
[Ir(COD)Cl]2 (2.5 mol%)
(S)-p-Tol-BINAP (5 mol%)
R1
R1
R1
H3C
H3C
O
R3COOH
+
AgOTf, Bu4NI, Et3N
R1
O
R3
°
C
THP, 80
R2
R2 OH
OH
5aa
yield 90%
1b: R1=H, R2=OCH3
1c: R1=OCH3, R2=H
1d: R1=CH3, R2=H
1e: R1=Br, R2=H
3a-3e
4a-4b
5a
6a
Entry Substrate R3COOH Product Time (h) Yield (%) eea(%)
COOH
1
2
1b
1b
3a
3b
24
26
62
65
11
10
Cl
COOH
r
B
Cl
COOH
COOH
3
1b
3c
18
64
28
Cl
4
5
6
7
8
9
1b
1b
1c
1c
1d
1e
3d
3e
4a
4b
5a
6a
24
30
48
48
48
48
60
66
nr
nr
nr
nr
20
17
–
H
3C
COOH
COOH
COOH
COOH
COOH
Cl
–
r
B
–
Cl
Cl
–
Conditions: [Ir(COD)Cl]2 (2.5 mol%), ligand (5.0 mol%), AgOTf (5 mol%), Bu4NI (5 mol%), substrate 1 (0.2 mmol), halide additive Bu4NI
(0.4 mmol), Et3N (1 mmol) and carboxylic acid (1 mmol) reacted in THP at 80 °C (oil bath temperature)
a
Determined by HPLC (Chiralcel AD-H or Chiralcel OD-H column)
Fig. 1 Optimized geometries for isomers of cis- and trans-2a
2px(O9)?r*(C11–H28) charge-transfer interaction, in
which the little E(2) values in cis-configuration (4.47 kcal/
mol) and trans-configuration (4.68 kcal/mol) are compa-
rable. However, the E(2) value with 17.24 kcal/mol of
2py(O10)?r*(O13–H31) charge-transfer in cis-configura-
tion is much larger than that in trans-configuration
(0.81 kcal/mol). Due to this strong O10 (2py)?O13–
H31(r*) delocalization, the cis-configuration is more sta-
ble than the trans-configuration.
In this work, the stability of the isomers of cis- and
trans-2a have been investigated by the density functional
theory B3LYP methods. The results show that cis and trans
isomers are both stable structures. The lower total molec-
ular energy, the shorter H31–O10 distance and the stronger
123

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabicyclic Alkenes
425
BINAP)I]2, is first formed through treatment of the pre-
catalyst, [Ir(COD)Cl]2, with AgOTf to remove the chloride
and followed by the addition of the (S)-p-Tol-BINAP
ligand, which replaces the 1.5-cyclooctadiene (COD)
ligand, and then the addition of Bu4NI. The oxygen atom
and the double bond of oxabenzonorbornadiene 1a are then
reversibly coordinated to the iridium center of the active
catalyst to give the intermediate B, followed by the oxi-
dative insertion of iridium catalyst into the C–O bond
forms C. Then carboxylic acid nucleophile attack with
configuration inversion is proposed to occur in an SN20
displacement of the iridium catalysis. Consequently, the
product 2 is subsequently released and the iridium complex
A is regenerated.
Table 6 Selected bond lengths (nm), bond angles (°) and dihedral
angles (°) of two isomers
cis-2a
trans-2a
C8–O9
0.1254
0.1444
0.1501
0.1594
0.1117
0.1474
0.1038
0.2063
0.1737
86.6130
112.0090
132.6460
26.9090
0.1256
C8–O10
0.1434
O10–C11
0.1492
C11–C12
0.1586
C11–H28
0.1119
C12–O13
0.1468
O13–H31
0.1029
O9–H28
0.2058
O10–H31
0.2594
C8–O9–H28
O9–H28–C11
O10–H31–O13
O10–C11–C12–O13
84.0410
111.9260
106.9920
-71.9220
3 Experimental
3.1 General
Table 7 The molecular energies, frontier orbital energy and the
energy difference (a.u.) between the two isomers
All flasks were flame-dried under a stream of nitrogen and
cooled before use. Solvents and solutions were transferred
with syringes and cannulae using standard inert atmosphere
techniques. Reagents were obtained from commercial
vendors and used without further purification. CH3CN and
DCE were distilled from calcium hydride. Toluene, DME,
dioxane, THF and THP were distilled from sodium ben-
zophenone ketyl immediately prior to use. Oxabenzonor-
bornadienes 1a–1e were prepared according to the
Coordination complex
cis-2a
trans-2a
Difference
E
-1325.3265
-0.1499
0.0282
-1325.3245
-0.1492
0.0242
0.00200
0.0007
EHOMO
ELUMO
Eg
-0.0040
-0.0047
0.1781
0.1734
Table 8 The second order perturbation stabilization energy E(2)
(kcal/mol) for OꢀꢀꢀH–O hydrogen bonds
1
literature procedures [1, 2]. All H and 13C NMR spectra
were recorded at 400 and 100 M NMR, respectively, using
1
Complex
Donor NBOs
Acceptor NBOs
E(2)(kcal/mol)
CDCl3 as solvent. The chemical shifts of all H and 13C
Cis
n(2px,O9)
n(2py,O10)
n(2px,O9)
n(2py,O10)
r*(C11–H28)
r*(O13–H31)
r*(C11–H28)
r*(O13–H31)
4.47
17.24
4.68
0.81
NMR spectra are referenced to the residual signal of CDCl3
1
(d 7.26 ppm) for the H NMR spectra) and (d 77.16 ppm)
for the 13C NMR spectra). Spectral features are tabulated in
the following order: Chemical shift (d, ppm); multiplicity
(s-singlet, d-doublet, t-triplet, m-multiplet); coupling con-
stants (J, Hz); number of protons. IR spectra were obtained
using a KBr pellet or using a neat film on a NaCl plate. MS
spectra were recorded on a Bruker esquire 6,000 mass
spectrometer (ESI). The melting points are uncorrected.
Crystal structure was determined by X-ray diffraction
apparatus.
Trans
n lone pair electron occupy orbital, r*, r anti-bonding orbital
2py(O10)?r*(O13–H31) charge-transfer in O13–H31ꢀꢀꢀO10
hydrogen bond indicate that the cis-configuration is more
stable than the trans-configuration.
The absolute configuration of ring-opened product 2a
was demonstrated by X-ray crystallography. The single
crystal was obtained by solvent evaporation from a solution
consisting of dichloromethane, petroleum ether, and ethyl
acetate. Its configuration was assigned as (1S,2S) and
confirmed as 1,2-trans-configuration by X-ray crystal
structure analysis, as shown in Fig. 2.
3.2 General Procedure
General procedure for the ARO reactions of oxabenzonor-
bornadienes 1a–1e with carboxylic acids. A 5.0 mL round-
bottomed flask fitted with a reflux condenser was flame-dried
under a stream of nitrogen and cooled to room temperature.
[Ir(COD)Cl]2 (3.3 mg, 2.5 mol%) and (S)-p-Tol-BINAP
(6.8 mg, 5 mol%) were simultaneously added and followed
by the addition of anhydrous THP (2.0 mL). After the mixture
Based on our findings and observations, a plausible
mechanism has been proposed for the formation of the
ring-opening products 2, as shown in Scheme 1. The active
catalyst of chiral dimeric iridium complex A, [Ir((S)-p-Tol-
123

426
Y. Long et al.
Fig. 2 ORTEP plot for 2a
(crystal data: C17H13ClO3,
M = 300.72; Orthorhombic
a = 5.6729(8), b = 8.3757(12),
c = 30.426(4), alpha = 90,
beta = 90, gamma = 90,
T = 296 K, space group, P21
21 21, Z = 4. wR2
(reflections) = 7241/2532.
CCDC-928839)
Scheme 1 Working hypothesis
for the ARO reaction of
oxabenzonorbornadiene 1a with
carboxylic acids
P
P
P(p-Tolyl)2
P(p-Tolyl)2
=
[Ir(COD)Cl]2
+
(S)-p-Tol-BINAP
Cl
Cl
P
P
P
P
Ir
Ir
Ir
AgOTf
Bu4NI
R
I
I
P
P
P
Ir
O
O
P
O
A
2
1a
OH
exo coordination
P
Ir
I
P
nucleophlic
displacement
O
O
P
P
Ir
I
COOH
C
B
R
oxidative insertion
was stirred for about 20 min, silver trifluoromethanesulfonate
(2.5 mg, 5 mol%) was added. After another 10 min, Bu4NI
(3.7 mg, 5 mol%) was added and the mixture was stirred for
10 min. To this mixture, substrate 1 (0.2 mmol) was added,
and then the mixture was heated. When the temperature of the
oil bath climbed to 80 °C, Bu4NI (147.7 mg, 2 equiv) and
Et3N (101.1 mg, 5 equiv) were added and followed by car-
boxylic acid (5 equiv). The reaction temperature was main-
tained at 80 °C until completion as judged by thin-layer
chromatography. The solvent was removed in vacuum, and
the crude mixture was then poured into dichloromethane and
washed three times with 5 % aqueous NaOH. The aqueous
layers were combined and back-extracted three times with
dichloromethane. The organic layers were combined, dried
over anhydrous Na2SO4, and then filtered. The filtrate was
concentratedinvacuum, and theresultingresiduewaspurified
by column chromatography on silica gel (silica gel: 200–300
mesh) to give the target product.
3.2.1 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
4-chlorobenzoat (2a)
Following general procedure I, 2a was obtained as a white
crystalline solid (37.2 mg, 62 %). The ee was determined to
123

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabicyclic Alkenes
427
be 70 % using HPLC analysis on a Chiralcel OD-H column
(hexane/2-propanol = 90/10, 1.0 mL/min, k = 254 nm).
Retention times were 10.1 min (minor) and 17.7 min
(major); Rf = 0.16 on silica gel (ethyl acetate/petroleum
ether = 1:10, v/v). mp 110–112 °C. [a]2D5 = ?151.99
(c = 1.00, CHCl3). IR (KBr, cm-1) 3425(br), 3059(w),
2958(m), 2926(m), 1718(s), 1595(m), 1456(m), 1394(m),
1269(s), 1103(s), 846(m), 790(m), 756(s); 1H NMR
(400 MHz, CDCl3) d 8.00 (d, J = 12.0 Hz, 2H), 7.59 (t,
J = 4.0 Hz, 1H), 7.42 (d, J = 6.0 Hz, 2H), 7.31 (t,
J = 4.0 Hz, 2H), 7.15 (t, J = 4.0 Hz, 1H), 6.58 (d,
J = 4.0 Hz, 1H), 5.97 (dd, J = 12.0, 8.0 Hz, 1H),
5.88–5.85 (m, 1H), 5.11 (d, J = 6.0 Hz, 1H), 2.54 (s, 1H);
13C NMR(100 MHz, CDCl3) d 165.9, 139.8, 135.2, 131.5,
131.2, 129.8, 128.8, 128.5, 128.5, 128.2, 126.9, 126.1, 125.1,
76.2, 71.9; MS (ESI) calcd for C17H13ClO3 (M?): 300.06;
Found: 301.34(M?H)?. Anal. Calcd for C17H13ClO3: C,
67.89; H, 4.36. Found: C, 67.92; H, 4.43.
Retention times were 11.9 min (minor) and 15.5 min
(major); Rf = 0.08 on silica gel (ethyl acetate/petroleum
ether = 1:10, v/v). [a]2D5 = ?146.10 (c = 1.00, CHCl3).
IR (KBr, cm-1) 3388(br), 3062(w), 2958(m), 2924(s),
2852(m), 1728(s), 1666(m), 1467(m), 1284(m), 1249(s),
1120(m), 1049(s), 978(m), 781(m), 750(s), 694(w),
1
644(w), 572(w); H NMR (400 MHz, CDCl3) d 7.78 (d,
J = 8.0 Hz, 1H), 7.52 (d, J = 4.0 Hz, 1H), 7.41–7.35 (m,
2H), 7.27–7.23 (m, 3H), 7.07 (d, J = 4.0 Hz, 1H), 6.51 (d,
J = 12.0 Hz, 1H), 5.96 (d, J = 8.0 Hz, 1H), 5.81 (d,
J = 8.0 Hz, 1H), 5.07 (d, J = 8.0 Hz, 1H), 2.44 (s, 1H);
13C NMR(100 MHz, CDCl3) d 165.9, 135.1, 133.7, 132.8,
131.6, 131.1, 129.9, 129.8, 128.4, 127.1, 126.8, 126.7,
126.0, 125.1, 121.2, 76.8, 71.7; MS (ESI) calcd for
C17H13ClO3 (M?): 300.06; Found: 323.08(M?Na)?. Anal.
Calcd for C17H13ClO3: C, 67.89; H, 4.36. Found: C, 67.77;
H, 4.39.
3.2.4 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
3.2.2 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
benzoate (2d)
3-chlorobenzoate (2b)
Following general procedure I, 2d was obtained as a white
crystalline solid (34.6 mg, 65 %). The ee was determined to
be 57 % using HPLC analysis on a Chiralcel OD-H column
(hexane/2-propanol = 90/10, 1.0 mL/min, k = 254 nm).
Retention times were 9.4 min (minor) and 12.0 min (major);
Rf = 0.09onsilicagel (ethylacetate/petroleum ether = 1:10,
v/v). mp 107–109 °C. [a]2D5 = ?74.46 (c = 1.00, CHCl3). IR
(KBr, cm-1) 3460(br), 3061(w), 2924(s), 1715(s), 1456(m),
1323(m), 1269(s), 1112(s), 975(w), 783(m), 709(m);1H NMR
(400 MHz, CDCl3) d 8.07 (d, J = 4.0 Hz, 2H), 7.61–7.56 (m,
2H), 7.45 (t, J = 8.0 Hz, 2H), 7.31 (t, 4.0 Hz, 2H), 7.15 (t,
J = 4.0 Hz, 1H), 6.58(d, J = 8.0 Hz, 1H), 6.00(dd, J = 8.0,
4.0 Hz, 1H), 5.89 (d, J = 8.0 Hz, 1H), 5.14 (d, J = 8.0 Hz,
1H), 2.64 (s, 1H); 13C NMR (100 MHz, CDCl3) d 166.8,
135.3, 133.3, 131.6, 129.8, 129.8, 129.7, 128.4, 128.4, 128.4,
126.8, 126.1, 125.4, 76.1, 72.0; MS (ESI) calcd for C17H14O3
(M?): 266.09; Found: 289.01(M?Na)?. Anal. Calcd for
C17H14O3: C, 76.68; H, 5.30. Found: C, 76.72; H, 5.34.
Following general procedure I, 2b was obtained as a white
crystalline solid (47.4 mg, 79 %). The ee was determined
to be 45 % using HPLC analysis on a Chiralcel OD-H
column (hexane/2-propanol = 90/10, 1.0 mL/min, k =
254 nm). Retention times were 18.4 min (minor) and
27.7 min (major); Rf = 0.10 on silica gel (ethyl acetate/
petroleum ether = 1:10, v/v). mp 124-126 °C. [a]D25
=
?107.27 (c = 1.00, CHCl3). IR (KBr, cm-1) 3502(br),
3032(w), 2924(s), 2854(m), 1722(s), 1460(m), 1284(m),
1255(s), 1130(m), 1078(m), 966(m), 813(w), 748(m),
1
644(w), 530(m); H NMR (400 MHz, CDCl3) d 8.04(s,
1H), 7.95 (d, J = 8.0 Hz, 1H), 7.60–7.54 (m, 2H), 7.39 (t,
J = 8.0 Hz, 1H), 7.31 (t, J = 4.0 Hz, 2H), 7.15 (t, J =
4.0 Hz, 1H), 6.59 (d, J = 4.0 Hz, 1H), 5.98 (dd, J = 8.0,
4.0 Hz, 1H), 5.88 (d, J = 8.0 Hz, 1H), 5.12 (d,
J = 8.0 Hz, 1H), 2.57 (s, 1H); 13C NMR (100 MHz,
CDCl3) d 165.6, 135.2, 134.6, 133.3, 129.9, 129.8, 129.7,
128.5, 128.4, 127.9, 126.9, 126.1, 125.0, 123.5, 117.8,
76.4, 71.9; MS (ESI) calcd for C17H13ClO3 (M?): 300.06;
Found: 323.17(M?Na)?. Anal. Calcd for C17H13ClO3: C,
67.89; H, 4.36. Found: C, 67.80; H, 4.40.
3.2.5 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
4-bromobenzoate (2e)
Following general procedure I, 2e was obtained as a white
crystalline solid (39.8 mg, 58 %). The ee was determined to
be 55 % using HPLC analysis on a Chiralcel OD-H column
(hexane/2-propanol = 90/10, 1.0 mL/min, k = 254 nm).
Retention times were 9.6 min (minor) and 16.4 min (major);
Rf = 0.11onsilicagel (ethylacetate/petroleum ether = 1:10,
v/v). mp 134–136 °C. [a]2D5 = ?92.59 (c = 1.00, CHCl3). IR
(KBr, cm-1) 3442(br), 3043(w), 2924(s), 2852(s), 1712(m),
3.2.3 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
2-chlorobenzoate (2c)
Following general procedure I, 2c was obtained as color-
less oil (39.1 mg, 65 %). The ee was determined to be
60 % using HPLC analysis on a Chiralcel OD-H column
(hexane/2-propanol = 90/10, 1.0 mL/min, k = 254 nm).
123

428
Y. Long et al.
1665(m), 1263(s), 1097(m), 1016(w), 980(w), 800(w),
754(m); 1H NMR (400 MHz, CDCl3) d 7.92 (d, J = 8.0 Hz,
2H), 7.59–7.57 (m, 3H), 7.32–7.30 (m, 2H), 7.15 (t,
J = 4.0 Hz, 1H), 6.58 (d, J = 12.0 Hz, 1H), 5.97 (dd,
J = 8.0,4.0 Hz, 1H),5.89–5.86(m, 1H), 5.11(d,J = 8.0 Hz,
1H), 2.53 (s, 1H); 13C NMR (100 MHz, CDCl3) d 166.1,
135.2, 131.8, 131.5, 131.4, 129.9, 128.7, 128.5, 128.5, 128.5,
126.9, 126.1, 125.1, 76.3, 71.9; MS (ESI) calcd for
C17H13BrO3 (M?): 344.00; Found: 369.26(M?Na)?. Anal.
Calcd for C17H13BrO3: C, 59.15; H, 3.80. Found: C, 59.07; H,
3.83.
J = 8.0 Hz, 1H), 6.02 (dd, J = 12.0, 4.0 Hz, 1H), 5.88 (d,
J = 8.0 Hz, 1H), 5.12 (d, J = 12.0 Hz, 1H), 2.67 (s, 3H),
2.60 (s, 1H); 13C NMR (100 MHz, CDCl3) d 167.8, 141.3,
135.3, 132.9, 131.9, 131.6, 130.8, 129.7, 129.2, 128.4, 126.8,
126.1, 125.9, 125.8, 125.5, 75.6, 72.0, 22.0; MS (ESI) calcd
for C18H16O3 (M?): 280.11; Found: 303.08(M?Na)?. Anal.
Calcd for C18H16O3: C, 77.12; H, 5.75. Found: C, 77.00; H,
5.78.
3.2.8 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
4-methylbenzoate (2h)
3.2.6 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl 2,4-
Following general procedure I, 2h was obtained as a white
crystalline solid (44.8 mg, 80 %). The ee was determined to
be 21 % using HPLC analysis on a Chiralcel OD-H column
(hexane/2-propanol = 90/10, 1.0 mL/min, k = 254 nm).
Retention times were 8.6 min (minor) and 13.2 min (major);
Rf = 0.18 on silica gel (ethyl acetate/petroleum ether = 1:8,
v/v). mp 106–108 °C. [a]2D5 = ?46.87(c = 1.00, CHCl3).
IR (KBr, cm-1) 3356(br), 3066(w), 2866(s), 1670(s),
1608(m), 1574(w), 1512(w), 1444(m), 1415(m), 1280(s),
1180(w), 1114(w), 956(w), 835(m), 752(m), 605(w),
542(w); 1H NMR(400 MHz, CDCl3) d 7.96 (d, J = 8.0 Hz,
2H), 7.60 (d, J = 4.0 Hz, 1H), 7.30 (t, J = 4.0 Hz, 2H),
7.26–7.23 (m, 2H), 7.15 (d, J = 4.0 Hz, 1H), 6.57 (d,
J = 8.0 Hz, 1H), 5.98 (dd, J = 12.0, 4.0 Hz, 1H), 5.87 (d,
J = 8.0 Hz, 1H), 5.13 (d, J = 8.0 Hz, 1H), 2.68 (s, 1H),
2.42 (s, 3H); 13C NMR (100 MHz, CDCl3) d 167.0, 144.1,
135.4, 131.6, 129.9, 129.6, 129.1, 128.4, 128.3, 127.0, 126.7,
126.0, 125.6, 76.1, 72.1, 21.7; MS (ESI) calcd for C18H16O3
(M?): 280.11; Found: 303.17(M?Na)?. Anal. Calcd for
C18H16O3: C, 77.12; H, 5.75. Found: C, 77.03; H, 5.79.
dichlorobenzoate (2f)
Following general procedure I, 2f was obtained as a white
crystalline solid (40.7 mg, 61 %). The ee was determined to
be 61 % using HPLC analysis on a Chiralcel OD-H column
(hexane/2-propanol = 90/10, 1.0 mL/min, k = 254 nm).
Retention times were 9.9 min (major) and 16.6 min (minor);
Rf = 0.12onsilicagel (ethylacetate/petroleum ether = 1:10,
v/v). mp 79–81 °C. [a]D25 = ?149.47 (c = 1.00, CHCl3). IR
(KBr, cm-1) 3356(br), 2926(s), 2854(s), 1730(s), 1666(s),
1539(m), 1555(w), 1462(m), 1276(m), 1188(m), 1101(w),
1051(m), 979(m), 867(w), 785(m), 690(w), 634(w); 1H NMR
(400 MHz, CDCl3) d 7.74 (d, J = 8.0 Hz, 1H), 7.49 (d,
J = 4.0 Hz, 1H), 7.40 (s, 1H), 7.22 (d, J = 4.0 Hz, 3H), 7.07
(d, J = 8.0 Hz, 1H), 6.51 (d, J = 8.0 Hz, 1H), 5.93 (d,
J = 8.0 Hz, 1H), 5.78 (d, J = 8.0 Hz, 1H), 5.04 (d,
J = 12.0 Hz, 1H), 2.48 (s, 1H);13C NMR (100 MHz, CDCl3)
d164.9,138.6,135.1,134.9,132.7,131.5,131.0,130.0,129.7,
128.5, 128.0, 127.1, 126.9, 126.0, 124.8, 76.7, 71.6; MS (ESI)
calcd for C17H12Cl2O3 (M?): 334.02; Found: 357.07
(M?Na)?. Anal. Calcd for C17H12Cl2O3: C, 60.92; H, 3.61.
Found: C, 60.83; H, 3.64.
3.2.9 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
4-methoxybenzoate (2i)
3.2.7 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
Following general procedure I, 2i was obtained as a white
crystalline solid (35.5 mg, 60 %). The ee was determined to
be 34 % using HPLC analysis on a Chiralcel OD-H column
(hexane/2- propanol = 90/10, 1.0 mL/min, k = 254 nm).
Retention times were 12.5 min (minor) and 21.8 min (major);
Rf = 0.07 on silica gel (ethyl acetate/petroleum ether = 1:8,
v/v). mp 118–120 °C. [a]2D5 = ?116.87 (c = 1.00, CHCl3).
IR (KBr, cm-1) 3469(br), 3001(w), 2958(m), 2926(s),
2853(m), 1711(s), 1605(s), 1458(m), 1419(m), 1325(w),
1259(s), 1168(s), 1103(s), 1028(s), 978(m), 960(m), 846(m),
772(m), 748(m), 696(m), 613(w), 572(w); 1H NMR
(400 MHz, CDCl3) d 8.02 (d, J = 12.0 Hz, 2H), 7.31–7.26
(m, 3H), 7.14 (t, J = 8.0 Hz, 1H), 6.92 (d, J = 8.0 Hz, 2H),
6.56 (d, J = 8.0 Hz, 1H), 5.98 (dd, J = 9.6 Hz, 2.8 Hz, 1H),
5.86 (tt, J = 9.2, 2.0 Hz, 1H), 5.12 (d, J = 8.0 Hz, 1H), 3.86
2-methylbenzoate (2g)
Following general procedure I, 2g was obtained as a white
crystalline solid (39.2 mg, 70 %). The ee was determined to
be 30 % using HPLC analysis on a Chiralcel OD-H column
(hexane/2-propanol = 90/10, 1.0 mL/min, k = 254 nm).
Retention times were 9.6 min (minor) and 12.4 min (major);
Rf = 0.21 on silica gel (ethyl acetate/petroleum ether = 1:8,
v/v). mp 88–90 °C. [a]D25 =?35.53(c = 1.00, CHCl3). IR
(KBr, cm-1) 3468(br), 3063(w), 2926(s), 2856(m), 1701(s),
1604(w), 1572(m), 1454(m), 1408(w), 1294(m), 1255(s),
1136(w), 1047(m), 922(m), 835(w), 741(s), 696(w), 657(w),
567(w); 1H NMR(400 MHz, CDCl3) d 8.07 (d, J = 4.0 Hz,
2H), 7.48–7.40 (m, 2H), 7.31–7.26 (m, 4H), 6.59 (d,
123

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabicyclic Alkenes
429
(s, 3H), 2.74 (s, 1H); 13C NMR (100 MHz, CDCl3) d 166.7,
163.6, 135.4, 131.9, 131.6, 129.5, 128.3, 128.2, 126.7, 126.0,
125.7, 122.1, 113.7, 76.0, 72.2, 55.5; MS (ESI) calcd for
C18H16O4 (M?): 296.10; Found: 319.13(M?Na)?. Anal.
Calcd for C18H16O4: C, 72.96; H, 5.44. Found: C, 72.84; H,
5.47.
284.08; Found: 283.57. Anal. Calcd for C17H13FO3: C,
71.82; H, 4.61. Found: C, 71.69; H, 4.64.
3.2.12 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
furan-2-carboxylate (2l)
Following general procedure I, 2l was obtained as a white
crystalline solid (34.8 mg, 68 %). The ee was determined
to be 46 % using HPLC analysis on a Chiralcel OD-H
column (hexane/2- propanol = 90/10, 1.0 mL/min,
k = 254 nm). Retention times were 11.8 min (minor) and
16.7 min (major); Rf = 0.29 on silica gel (ethyl acetate/
3.2.10 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
4-(trifluoromethyl)benzoate (2j)
Following general procedure I, 2j was obtained as a white
crystalline solid (42.7 mg, 64 %). The ee was determined
to be 44 % using HPLC analysis on a Chiralcel OD-H
column (hexane/2-propanol = 85/15, 1.0 mL/min, k =
254 nm). Retention times were 6.2 min (minor) and
8.5 min (major); Rf = 0.15 on silica gel (ethyl acetate/
petroleum ether = 1:5, v/v). mp 99–100 °C. [a]D25
=
?111.54(c = 1.00, CHCl3). IR (KBr, cm-1) 3452(br),
3034(w), 2924(s), 2854(m), 1716(s), 1575(m), 1473(m),
1394(m), 1292(m), 1178(s), 1118(s), 1016(w), 977(m),
855(w), 761(s), 696(w), 642(w), 602(w), 515(w); 1H NMR
(400 MHz, CDCl3) d 7.61–7.60 (m, 1H), 7.31–7.26 (m,
4H), 7.14 (d, J = 8.0 Hz, 1H), 6.56 (t, J = 8.0 Hz, 2H),
5.96 (d, J = 12.0 Hz, 1H), 5.86 (d, J = 8.0 Hz, 1H), 5.12
(d, J = 12.0 Hz, 1H), 2.51 (s, 1H); 13C NMR(100 MHz,
CDCl3) d 158.8, 146.7, 144.2, 135.2, 131.5, 129.8, 128.4,
128.3, 126.8, 125.9, 125.2, 118.8, 112.0, 76.3, 71.9; MS
(ESI) calcd for C15H12O4 (M?): 256.07; Found: 255.24.
Anal. Calcd for C15H12O4: C, 70.31; H, 4.72. Found: C,
70.20; H, 4.75.
petroleum ether = 1:8, v/v). mp 121–123 °C. [a]D25
=
?84.91 (c = 1.00, CHCl3). IR (KBr, cm-1) 3446(br),
2958(m), 2924(s), 2852(m), 1705(s), 1651(s), 1462(w),
1411(w), 1325(m), 1265(m), 1168(m), 1124(s), 1062(w),
1024(w), 858(m), 779(m), 700(m), 646(w); 1H
NMR(400 MHz, CDCl3) d 8.18 (d, J = 4.0 Hz, 2H), 7.72
(d, J = 8.0 Hz, 2H), 7.32–7.26 (m, 4H), 6.61 (d,
J = 8.0 Hz, 1H), 6.00 (d, J = 8.0 Hz, 1H), 5.91 (d,
J = 8.0 Hz, 1H), 5.13 (d, J = 8.0 Hz, 1H), 3.29 (s, 1H);
13C NMR(100 MHz, CDCl3) d 165.3, 135.1, 132.9, 131.5,
130.2, 130.1, 128.5, 126.9, 126.1, 125.5, 125.4, 124.9,
76.4, 71.8; MS (ESI) calcd for C18H13F3O3 (M?): 334.08;
Found: 333.68. Anal. Calcd for C18H13F3O3: C, 64.67; H,
3.92. Found; C, 64.52; H, 3.95.
3.2.13 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
3-methoxybenzoate (2m)
3.2.11 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
Following general procedure I, 2m was obtained as a white
crystalline solid (39.1 mg, 66 %). The ee was determined
to be 35 % using HPLC analysis on a Chiralcel OD-H
column (hexane/2- propanol = 95/5, 1.0 mL/min, k =
254 nm). Retention times were 19.5 min (minor) and
32.5 min (major); Rf = 0.09 on silica gel (ethyl acetate/
4-fluorobenzoate (2k)
Following general procedure I, 2k was obtained as a white
crystalline solid (35.2 mg, 62 %). The ee was determined
to be 33 % using HPLC analysis on a Chiralcel OD-H
column (hexane/2- propanol = 85/15, 1.0 mL/min,
k = 254 nm). Retention times were 6.5 min (minor) and
9.6 min (major); Rf = 0.25 on silica gel (ethyl acetate/
petroleum ether = 1:8, v/v). mp 111–113 °C. [a]D25
=
?185.01 (c = 1.00, CHCl3). IR (KBr, cm-1) 3433 (br),
3014(w), 2924(s), 2852(m), 1712(s), 1593(m), 1460(m),
1276(s), 1226(m), 1182(w), 1109(m), 1043(m), 979 (m),
906(w), 754(s), 578(w), 532(w); 1H NMR (400 MHz,
CDCl3) d 7.66 (d, J = 8.0 Hz, 1H), 7.61–7.58 (m, 2H),
7.37–7.29 (m, 3H), 7.13 (t, J = 8.0 Hz, 2H), 6.57 (d,
J = 8.0 Hz, 1H), 5.99 (dd, J = 9.6 Hz, 2.4 Hz, 1H), 5.88
(dd, J = 8.8 Hz,1.6 Hz, 1H), 5.14 (d, J = 8.0 Hz, 1H),
3.84 (s, 3H), 2.90 (s, 1H); 13C NMR(100 MHz, CDCl3) d
166.7, 159.5, 135.3, 131.6, 131.1, 129.7, 129.5, 128.4,
128.3, 126.8, 126.0, 125.4, 122.2, 119.7, 114.3, 76.3, 72.0,
55.5; MS (ESI) calcd for C18H16O4 (M?): 296.10; Found:
295.20. Anal. Calcd for C18H16O4: C, 72.96; H, 5.44.
Found; C, 72.82; H, 5.48.
petroleum ether = 1:8, v/v). mp 98–100 °C. [a]D25
=
?81.69 (c = 1.00, CHCl3). IR (KBr, cm-1) 3460(br),
3064(w), 2924(s), 2853(s), 1701(s), 1602(s), 1506(m),
1458(m), 1327(w), 1267(s), 1240(m), 1155(m), 1114(m),
1091(m), 979(w), 854(m), 767(m), 692(w); 1H NMR(400 MHz,
CDCl3) d 8.09 (t, J = 2.0 Hz, 2H), 7.60 (s, 1H), 7.31 (d,
J = 2.8 Hz, 2H), 7.12 (t, J = 8.0 Hz, 3H), 6.58
(d, J = 12.0 Hz, 1H), 5.98 (d, J = 12.0 Hz, 1H), 5.87 (d,
J = 8.0 Hz, 1H), 5.12 (d, J = 8.0 Hz, 1H), 2.55 (s, 1H);
13C NMR(100 MHz, CDCl3) d 167.2, 165.9, 135.2, 132.5,
132.4, 131.5, 129.8, 128.5, 126.8, 126.1, 125.2, 115.7,
115.5, 76.1, 72.0; MS (ESI) calcd for C17H13FO3 (M?):
123

430
Y. Long et al.
3.2.14 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
3.2.16 (1S,2S)-1-Hydroxy-5,8-dimethoxy-1,2-
1-naphthoate (2n)
dihydronaphthalen-2-yl 4-chlorobenzoate (3a)
Following general procedure I, 2n was obtained as a white
crystalline solid (39.8 mg, 63 %). The ee was determined
to be 43 % using HPLC analysis on a Chiralcel AD-H
Following general procedure I, 3a was obtained as yellow
oil (44.6 mg, 62 %). The ee was determined to be 11 %
using HPLC analysis on a Chiralcel OD-H column (hex-
column
(hexane/2-propanol = 90/10,
1.0 mL/min,
ane/2-propanol = 90/10,
1.0 mL/min,
k = 254 nm).
k = 254 nm). Retention times were 26.9 min (minor) and
31.2 min (major); Rf = 0.16 on silica gel (ethyl acetate/
Retention times were 20.4 min (major) and 25.0 min
(minor); Rf = 0.13 on silica gel (ethyl acetate/petroleum
ether = 1:5, v/v). [a]2D5 = ?7.22 (c = 1.00, CHCl3). IR
petroleum ether = 1:8, v/v). mp 87–88 °C. [a]D25
=
?90.54(c = 1.00, CHCl3). IR (KBr, cm-1) 3441(br),
3051(w), 2955(m), 2924(s), 2853(m), 1713(s), 1573(w),
1394(m), 1276(m), 1242(m), 1195(m), 1136(m), 1076(w),
999(w), 871(w), 781(s), 748(w), 696(w), 563(w); 1H NMR
(400 MHz, CDCl3) d 8.91 (d, J = 12.0 Hz, 1H), 8.22 (d,
J = 8.0 Hz, 1H), 8.05 (d, J = 8.0 Hz, 1H), 7.89 (d,
J = 8.0 Hz, 1H), 7.65–7.48 (m, 4H), 7.32 (t, J = 4.0 Hz,
2H), 7.17 (t, J = 4.0 Hz, 1H), 6.62 (d, J = 12.0 Hz, 1H),
6.10 (dd, J = 12.0, 4.0 Hz, 1H), 5.99 (d, J = 8.0 Hz, 1H),
5.19 (d, J = 8.0 Hz, 1H), 2.58 (s, 1H); 13C
NMR(100 MHz, CDCl3) d 167.7, 135.4, 133.8, 133.7,
131.6, 131.3, 130.5, 129.8, 128.6, 128.4, 128.0, 127.9,
126.8, 126.7, 126.3, 126.1, 125.7, 125.5, 124.5, 75.9, 72.0;
MS (ESI) calcd for C21H16O3 (M?): 316.11; Found:
339.15(M?Na)?. Anal. Calcd for C21H16O3: C, 79.73; H,
5.10. Found: C, 79.60; H, 5.14.
(KBr, cm-1
) 3466(br), 3057(w), 2999(s), 2837(m),
1716(s), 1593(m), 1485(s), 1460(w), 1400(m), 1313(w),
1263(s), 1170(w), 1093(m), 1035(w), 1018(w), 950(m),
850(w), 802(m), 758(m), 717(m), 528(w); 1H NMR
(400 MHz, CDCl3) d 7.88 (d, J = 8.0 Hz, 2H), 7.33 (d,
J = 8.0 Hz, 2H), 6.83 (s, 2H), 6.64 (d, J = 4.0 Hz, 1H),
6.14 (s, 1H), 5.73 (s, 1H), 5.26 (s, 1H), 3.83 (d,
J = 12.0 Hz, 6H), 3.56 (s, 1H); 13C NMR(100 MHz,
CDCl3) d 165.1, 151.4, 150.0, 139.4, 131.2, 128.6, 128.5,
125.1, 123.1, 121.9, 121.1, 111.6, 111.4, 71.1, 64.8, 56.1,
56.0; MS (ESI) calcd for C19H17ClO5 (M?): 360.08;
Found: 383.10(M?Na)?. Anal. Calcd for C19H17ClO5: C,
63.25; H, 4.75. Found: C, 63.13; H, 4.77.
3.2.17 (1S,2S)-1-Hydroxy-5,8-dimethoxy-1,2-
dihydronaphthalen-2-yl 4-bromobenzoate (3b)
Following general procedure I, 3b was obtained as yellow oil
(52.5 mg, 65 %). The ee was determined to be 10 % using
HPLC analysis on a Chiralcel OD-H column (hexane/2-pro-
panol = 90/10, 1.0 mL/min, k = 254 nm). Retention times
were 20.2 min (major) and 23.1 min (minor); Rf = 0.11 on
silica gel (ethyl acetate/petroleum ether = 1:5, v/v).
[a]2D5 = ?8.06 (c = 1.00, CHCl3). IR (KBr, cm-1) 3394(br),
2997(w), 2926(s), 2854(m), 1718(m), 1668(w), 1489(m),
1398(m), 1363(w), 1261(s), 1186(w), 1093(m), 966(w),
800(w), 715(m), 597(w); 1H NMR (400 MHz, CDCl3) d 7.81
(d, J = 8.0 Hz, 2H), 7.50 (d, J = 8.0 Hz, 2H), 7.15 (d,
J = 8.0 Hz, 1H), 6.84 (s, 2H), 6.16–6.12 (m, 1H), 5.74–5.72
(m, 1H), 5.26 (s, 1H), 3.83 (d, J = 12.0 Hz, 6H), 3.65 (s, 1H);
13C NMR(100 MHz, CDCl3) d 165.3, 151.4, 149.9, 131.6,
131.3, 129.0, 128.1, 125.1, 123.1, 121.9, 121.1, 111.6, 111.4,
71.1, 64.8, 56.1, 56.0; MS (ESI) calcd for C19H17BrO5 (M?):
404.03; Found: 429.01(M?Na)?. Anal. Calcd for
C19H17BrO5: C, 56.31; H, 4.23. Found: C, 56.22; H, 4.27.
3.2.15 (1S,2S)-1-Hydroxy-1,2-dihydronaphthalen-2-yl
pivalate (2o)
Following general procedure I, 2o was obtained as a white
crystalline solid (36.9 mg, 75 %). The ee was determined
to be 25 % using HPLC analysis on a Chiralcel OD-H
column (hexane/2-propanol = 90/10, 1.0 mL/min, k =
254 nm). Retention times were 5.2 min (minor) and
7.7 min (major); Rf = 0.33 on silica gel (ethyl acetate/
petroleum ether = 1:10, v/v). mp 110–112 °C. [a]D25
=
?59.09 (c = 1.00, CHCl3). IR (KBr, cm-1) 3356(br),
3049(w), 2964(m), 2924(s), 2854(m), 1718(s), 1577(w),
1479(m), 1456(m), 1394(m), 1276(s), 1151(s), 1024(m),
958(m), 935(w), 796(m), 771(s), 632(w), 559(m), 524(m),
451(m); 1H NMR (400 MHz, CDCl3)
d 7.57 (d,
J = 4.0 Hz, 1H), 7.29–7.26 (m, 2H), 7.11 (d, J = 8.0 Hz,
1H), 6.50 (d, J = 12.0 Hz, 1H), 5.83 (dd, J = 9.6, 2.0 Hz,
1H), 5.62 (d, J = 8.0 Hz, 1H), 4.97 (d, J = 8.0 Hz, 1H),
2.54 (s, 1H), 1.25 (s, 9H); 13C NMR(100 MHz, CDCl3) d
178.8, 135.5, 131.6, 129.3, 128.3, 128.2, 126.6, 125.7,
125.6, 75.6, 72.3, 38.9, 26.8; MS (ESI) calcd for C15H18O3
(M?): 246.13; Found: 269.20(M?Na)?. Anal. Calcd for
C15H18O3: C, 73.15; H, 7.37. Found: C, 73.02; H, 7.40.
3.2.18 (1S,2S)-1-Hydroxy-5,8-dimethoxy-1,2-
dihydronaphthalen-2-yl 2,4-dichlorobenzoate (3c)
Following general procedure I, 3c was obtained as yellow
oil (50.5 mg, 64 %). The ee was determined to be 28 %
123

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabicyclic Alkenes
using HPLC analysis on a Chiralcel AD-H column (hex-
431
(minor); Rf = 0.17 on silica gel (ethyl acetate/petroleum
ether = 1:5, v/v). [a]D25 = ?30.28 (c = 1.00, CHCl3). IR
ane/2-propanol = 90/10,
1.0 mL/min,
k = 254 nm).
Retention times were 32.4 min (major) and 49.3 min
(minor); Rf = 0.14 on silica gel (ethyl acetate/petroleum
ether = 1:5, v/v). [a]D25 = ?69.23 (c = 1.00, CHCl3). IR
(KBr, cm-1
) 3477(br), 3061(w), 2999(m), 2935(s),
2839(m), 1712(s), 1599(m), 1485(s), 1456(m), 1317(m),
1261(m), 1182(w), 1109(m), 1068(w), 1028(w), 948(m),
802(s), 752(m), 713(s), 590(w), 540(w); 1H NMR
(400 MHz, CDCl3) d 7.96 (d, J = 8.0 Hz, 2H), 7.51 (t,
J = 8.0 Hz, 1H), 7.37 (t, J = 8.0 Hz, 2H), 7.15 (d,
J = 8.0 Hz, 1H), 6.84 (s, 2H), 6.18–6.15 (m, 1H),
5.76–5.74 (m, 1H), 5.28 (s, 1H), 3.84 (dd, J = 12.0,
4.0 Hz, 6H), 3.78 (s, 1H); 13C NMR(100 MHz, CDCl3) d
166.0, 151.5, 150.0, 132.9, 130.1, 129.8, 128.2, 125.0,
123.2, 122.1, 121.2, 111.6, 111.4, 70.7, 64.7, 56.1, 56.0;
MS (ESI) calcd for C19H18O5 (M?): 326.12; Found:
349.13(M?Na)?. Anal. Calcd for C19H18O5: C, 69.93; H,
5.56. Found: C, 69.80; H, 5.61.
(KBr, cm-1
) 3387(br), 3072(w), 2999(m), 2926(s),
2846(m), 1707(s), 1612(m), 1587(m), 1460(m), 1400(s),
1300(w), 1259(s), 1141(w), 1095(s), 968(m), 835(m),
802(m), 761(w), 719(m), 673(m), 586(w); 1H NMR
(400 MHz, CDCl3) d 7.94 (d, J = 8.0 Hz, 1H), 7.50 (s,
2H), 7.25 (s, 2H), 6.82 (s, 1H), 6.18–6.15 (m, 1H), 5.73 (m,
1H), 5.27 (s, 1H), 4.01 (s, 6H), 3.76 (s, 1H); 13C
NMR(100 MHz, CDCl3) d 154.3, 150.0, 138.9, 135.6,
133.3, 131.3, 128.3, 127.3, 127.1, 119.4, 113.0, 111.3,
111.0, 103.2, 102.9, 81.9, 75.2, 56.3, 55.7; MS (ESI) calcd
for C19H16Cl2O5 (M?): 394.04; Found: 416.98(M?Na)?.
Anal. Calcd for C19H16Cl2O5: C, 57.74; H, 4.08. Found: C,
57.61; H, 4.11.
3.2.21 6,7-Dimethylnaphthalen-1-ol (5aa)
3.2.19 (1S,2S)-1-Hydroxy-5,8-dimethoxy-1,2-
5aa was obtained as a white solid following purification by
column chromatography (Rf = 0.21, ethyl acetate : petro-
leum ether = 1 : 10, v/v). m.p. 138–140 °C. 1H NMR
(400 MHz, CDCl3) d 7.90 (s, 1H), 7.56 (s, 1H), 7.32 (d,
J = 8.0 Hz, 1H), 7.20 (t, J = 8.0 Hz, 1H), 6.73 (d,
J = 8.0 Hz, 1H), 5.44 (s, 1H), 2.43 (d, J = 8.0 Hz, 6H);
13C NMR(100 MHz, CDCl3) d 150.9, 136.1, 134.9, 133.7,
127.3, 124.9, 123.0, 121.0, 119.6, 107.8, 20.4, 20.2.
Spectroscopic data for 5aa was in agreement with values
reported in the literature [76, 77].
dihydronaphthalen-2-yl 4-methylbenzoate (3d)
Following general procedure I, 3d was obtained as yellow
oil (40.8 mg, 60 %). The ee was determined to be 20 %
using HPLC analysis on a Chiralcel AD-H column (hex-
ane/2-propanol = 90/10,
1.0 mL/min,
k = 254 nm).
Retention times were 10.9 min (major) and 15.3 min
(minor); Rf = 0.16 on silica gel (ethyl acetate/petroleum
ether = 1:5, v/v). [a]D25 = ?33.46 (c = 1.00, CHCl3). IR
(KBr, cm-1
) 3468(br), 3049(w), 2999(m), 2926(s),
2852(m), 1712(s), 1610(m), 1498(s), 1485(s), 1462(m),
1298(w), 1261(s), 1718(w), 1095(m), 1066(m), 960(w),
800(m), 756(m), 713(m), 646(w), 594(w); 1H NMR
(400 MHz, CDCl3) d 7.85 (d, J = 8.0 Hz, 2H), 7.18–7.13
(m, 3H), 6.83 (d, J = 4.0 Hz, 2H), 6.18–6.14 (m, 1H), 5.74
(t, J = 4.0 Hz, 1H), 5.27 (s, 1H), 3.83 (dd, J = 10.4,
2.0 Hz, 6H), 3.77 (s, 1H), 2.37 (s, 3H); 13C
NMR(100 MHz, CDCl3) d 166.0, 151.5, 149.9, 143.6,
129.8, 128.9, 127.3, 124.8, 123.3, 122.3, 121.1, 111.6,
111.3, 70.5, 64.8, 56.1, 56.0, 21.7; MS (ESI) calcd for
C20H20O5 (M?): 340.13; Found: 363.18(M?Na)?. Anal.
Calcd for C20H20O5: C, 70.57; H, 5.92. Found: C, 70.42; H,
5.96.
4 Conclusions
In summary, we have first successfully developed a novel
iridium(I)-catalyzed ARO of oxabicyclic alkenes with
various carboxylic acids, which afforded the corresponding
substituted carboxylic acid 1-hydroxy-1,2-dihydronaphth-
alen-2-yl ester products in moderate yields with good
enantioselectivities under mild conditions. The utility of
these products has been demonstrated through their appli-
cation in the preparation of 1,4-dihydronaphthalenes. The
hydronaphthalene products of these reactions constitute an
important molecular scaffold in medicinal chemistry.
Future study will be focused on their activities of biological
and pharmaceutical.
3.2.20 (1S,2S)-1-Hydroxy-5,8-dimethoxy-1,2-
dihydronaphthalen-2-yl benzoate (3e)
Acknowledgments We are grateful to the National Natural Science
Foundation of China (21372090, 21172081), Produce and Learning
and Research Project of Education Department of Guangdong Prov-
ince (2011A090200039), the Natural Science Foundation of Guang-
dong Province (S2013020013091 and S2012010008763) and
Guangzhou Pearl River New Star Plan of Science and Technology
Program (2012J2200015) for financial support.
Following general procedure I, 3e was obtained as yellow
oil (43.1 mg, 66 %). The ee was determined to be 17 %
using HPLC analysis on a Chiralcel AD-H column (hex-
ane/2-propanol = 90/10,
1.0 mL/min,
k = 254 nm).
Retention times were 29.3 min (major) and 33.7 min
123

432
Y. Long et al.
37. Imamoto T, Saitoh Y, Koide A, Ogura T, Yoshida K (2007)
Angew Chem Int Ed 46:8636–8639
References
38. Zhang TK, Yuan K, Hou XL (2007) J Organomet Chem
692:1912–1919
39. Zhang TK, Mo DL, Dai LX, Hou XL (2008) Org Lett
10:3689–3692
40. Endo K, Tanaka K, Ogawa M, Shibata T (2011) Org Lett
13:868–871
41. Huang XJ, Mo DL, Ding CH, Hou XL (2011) Synlett 7:943–946
42. Lautens M, Fagnou K, Rovis T (2000) J Am Chem Soc
122:5650–5651
1. Rayabarapu DK, Cheng CH (2007) Acc Chem Res 40:971–983
2. Nakamura M, Matsuo K, Inoue T, Nakamura E (2003) Org Lett
5:1373–1375
3. Feng CC, Nandi M, Sambaiah T, Cheng CH (1999) J Org Chem
64:3538–3543
4. Rayabarapu DK, Chiou CF, Cheng CH (2002) Org Lett
4:1679–1682
5. Li LP, Rayabarapu DK, Nandi M, Cheng CH (2003) Org Lett
5:1621–1624
43. Lautens M, Fagnou K, Taylor M (2000) Org Lett 2:1677–1679
44. Leong P, Lautens M (2004) J Org Chem 69:2194–2196
45. Cho YH, Zunic V, Senboku H, Olsen M, Lautens M (2006) J Am
Chem Soc 128:6837–6846
46. Gomez Arrayas R, Cabrera S, Carretero JC (2003) Org Lett
5:1333–1336
47. Arrayas RG, Cabrera S, Carretero JC (2005) Org Lett 7:219–221
48. Zhang W, Wang LX, Shi WJ, Zhou QL (2005) J Org Chem
70:3734–3736
49. Arrayas RG, Cabrera S, Carretero JC (2006) Synthesis 7:1205–1219
50. Ogura T, Yoshida K, Yanagisawa A, Imamoto T (2009) Org Lett
11:2245–2248
51. Lautens M, Dockendorff C, Fagnou K, Malicki A (2002) Org Lett
4:1311–1314
52. Murakami M, Igawa H (2002) Chem Commun 390–391
53. Nishimura T, Tsurumaki E, Kawamoto T, Guo XX, Hayashi T
(2008) Org Lett 10:4057–4060
54. Wu MS, Jeganmohan M, Cheng CH (2005) J Org Chem
70:9545–9550
55. Cho YH, Tseng NW, Senboku H, Lautens M (2008) Synthesis
15:2467–2475
56. Ohmura T, Hartwig JF (2002) J Am Chem Soc 124:15164–15165
57. Yamashita Y, Gopalarathnam A, Hartwig JF (2007) J Am Chem
Soc 129:7508–7509
58. Weix DJ, Hartwig JF (2007) J Am Chem Soc 129:7720–7721
59. Nomura N, Komiyama S, Kasugai H, Saba M (2008) J Am Chem
Soc 130:812–814
60. Woodward S (2005) Angew Chem Int Ed 44:5560–5562
61. Hayashi T, Yamasaki K (2003) Chem Rev 103:2829–2844
62. Raskatov JA, Spiess S, Gnamm C, Broedner K, Rominger F,
Helmchen G (2010) Chem -Eur J 16:6601–6615
63. Spiess S, Welter C, Franck G, Taquet JP, Helmchen G (2008)
Angew Chem Int Ed 47:7652–7655
64. Helmchen G, Dahnz A, Duebon P, Schelwies M, Weihofen R
(2007) Chem Commun 7:675–691
65. Yang DQ, Long YH, Wang H, Zhang ZM (2008) Org Lett
10:4723–4726
66. Yang DQ, Hu P, Long YH, Wu YJ, Zeng HP, Wang H, Zuo XJ
(2009) Beilstein J Org Chem 5:30
67. Long YH, Yang DQ, Zhang ZM, Wu YJ, Zeng HP, Chen Y
(2010) J Org Chem 75:7291–7299
6. Rayabarapu DK, Cheng CH (2003) Chem –Eur J 9:3164–3169
7. Bertozzi F, Pineschi M, Macchia F, Arnold LA, Minnaard AJ,
Feringa BL (2002) Org Lett 4:2703–2705
8. Millet R, Bernardez T, Palais L, Alexakis A (2009) Tetrahedron
Lett 50:3474–3477
9. Millet R, Gremaud L, Bernardez T, Palais L, Alexakis A (2009)
Synthesis 12:2101–2112
10. Bos PH, Rudolph A, Perez M, Fananas-Mastral M, Harutyunyan
SR, Feringa BL (2012) Chem Commun 48:1748–1750
11. Villeneuve K, Tam W (20006) J Am Chem Soc 128:3514–3515
12. Burton RR, Tam W (2007) Org Lett 9:3287–3290
13. Carreras J, Avenoza A, Busto JH, Peregrina JM (2007) Org Lett
9:1235–1238
14. Cortez GA, Baxter CA, Schrock RR, Hoveyda AH (2007) Org
Lett 9:2871–2874
15. Ballantine M, Menard ML, Tam W (2009) J Org Chem
74:7570–7573
16. Machin BP, Howell J, Mandel J, Blanchard N, Tam W (2009)
Org Lett 11:2077–2080
17. Tenaglia A, Marc S, Giordano L, De Riggi I (2011) Angew Chem
Int Ed 50:9062–9065
18. Lautens M, Fagnou K (2001) J Am Chem Soc 123:7170–7171
19. Lautens M, Fagnou K (2001) Tetrahedron 57:5067–5072
20. Lautens M, Fagnou K, Taylor M, Rovis T (2001) J Organomet
Chem 624:259–270
21. Lautens M, Fagnou K, Zunic V (2002) Org Lett 4:3465–3468
22. Lautens M, Fagnou K, Yang DQ (2003) J Am Chem Soc
125:14884–14892
23. Allen A, Le Marquand P, Burton R, Villeneuve K, Tam W (2007)
J Org Chem 72:7849–7857
24. Long YH, Yang DQ, Zeng HP, Xie L, Wu LH, Mo HH, Zuo XJ
(2010) Chin J Chem 28:235–242
25. Long YH, Zhao SQ, Zeng HP, Yang DQ (2010) Catal Lett
138:124–133
26. Nguyen TD, Webster R, Lautens
13:1370–1373
M (2011) Org Lett
27. Wolthuis E (1961) J Org Chem 26:2215–2220
28. Lautens M, Renaud JL, Hiebert S (2000) J Am Chem Soc
122:1804–1805
29. Lautens M, Dockendorff C (2003) Org Lett 5:3695–3698
30. Cabrera S, Gomez Arrayas R, Carretero JC (2004) Angew Chem
Int Ed 43:3944–3947
31. Dotta P, Kumar PGA, Pregosin PS, Albinati A, Rizzato S (2004)
Organometallics 23:2295–2304
32. Lautens M, Hiebert S (2004) J Am Chem Soc 126:1437–1447
33. Li M, Yan XX, Hong W, Zhu XZ, Cao BX, Sun J, Hou XL
(2004) Org Lett 6:2833–2835
34. Cabrera S, Gomez Arrayas R, Alonso I, Carretero JC (2005) J Am
Chem Soc 127:17938–17947
35. Imamoto T, Sugita K, Yoshida K (2005) J Am Chem Soc
127:11934–11935
36. Chen CL, Martin SF (2006) J Org Chem 71:4810–4817
68. Yang DQ, Long YH, Zhang JF, Zeng HP, Wang SY, Li CR
(2010) Organometallics 29:3477–3480
69. Yang DQ, Long YH, Wu YJ, Zuo XJ, Tu QQ, Fang S, Jiang LS,
Wang SY, Li CR (2010) Organometallics 29:5936–5940
70. Fang S, Liang XL, Long YH, Li XL, Yang DQ, Wang SY, Li CR
(2012) Organometallics 31:3113–3118
71. Chen HC, Yang DQ (2012) J Org Chem 77:9756–9765
72. Yang DQ, Xia JY, Long YH, Zeng ZY, Zuo XJ, Wang SY, Li CR
(2013) Org Biomol Chem 11:4871–4881
73. Freeman JP, Michalson ET, D’Andrea SV, Baczynskyj L, Vo-
nVoigtlander PF, Lahti RA, Smith M W, Lawson CF, Scahill
123

Iridium-Catalyzed Asymmetric Ring-Opening of Oxabicyclic Alkenes
433
TA, Mizsak SA, Szmuszkovicz
34:1891–1896
74. Becke AD (1993) J Chem Phys 98:5648–5652
75. Nguyen HMT, Nguyen MT, Peeters J (2004) J Phys Chem A
108:11101–11108
J
(1991)
J
Med Chem
76. Hart H, Bashir-Hashemi A, Luo J, Meador MA (1986) Tetrahe-
dron 42:1641–1654
77. Hart H, Lai CY, Nwokogu GC, Shamouilian S (1987) Tetrahe-
dron 43:5203–5224
123