C.-H. Cheng et al.
140.51 (C), 135.56 (C), 134.59(CH), 129.64 (CH), 129.09 (CH), 127.93
(CH), 127.70 (CH), 127.36 (CH), 125.93 (CH), 123.13 (CH), 114.46 (CH),
82.72 ppm (CH); HRMS: m/z: calcd for C20H14O2: 286.0994; found:
286.0992.
potential of using cobalt as an inexpensive and efficient cat-
alyst for coupling of carbon–carbon bonds and for catalytic
asymmetric synthesis.
3-Benzo
(400 MHz, CDCl3): d=5.59 (s, 2H; CH2), 6.30 (s, 1H; CH), 6.58 (s, 1H;
HC=), 6.82–6.77 (m, 2H; aromatic H), 7.30 (d, 3J
(H,H)=7.6 Hz, 1H;
HC=), 7.54 (t, 3J(H,H)=7.2 Hz, 1H; HC=), 7.64 (t, 3J
(H,H)=7.2 Hz,
1H; HC=), 7.94 ppm (d, 3J(H,H)=7.2 Hz, 1H; HC=); 13C NMR
(100 MHz, CDCl3): d=170.31 (C=O), 149.51 (C), 148.52 (C), 148.21 (C),
134.27 (CH), 129.98 (C), 129.37 (CH), 125.77(C), 125.57 (CH), 122.87
(CH), 121.48 (CH), 108.39 (CH), 107.25 (CH), 101.40 (CH2), 82.70 ppm
(CH); HRMS: m/z: calcd for C15H10O4: 254.0579; found 254.0578.
A
(3j):
1H NMR
AHCTREUNG
Experimental Section
ACHTREUNG
All reactions were conducted under a nitrogen atmosphere on a dual-
manifold Schlenk line by using purified deoxygenated solvents and stan-
dard inert atmosphere techniques, unless otherwise stated. Reagents and
chemicals were used as purchased without further purification.
1H NMR
General procedure for the cyclization of 2-iodobenzoates1 with alde-
hydes2 : A sealed tube containing [CoI2CAHTRE(UNG dppe)] (0.050 mmol, 5.0 mol%)
4,5,6-Trimethoxy-3-phenylisobenzofuran-1(3H)one
(400 MHz, CDCl3): d=3.42 (s, 3H; OCH3), 3.87 (s, 3H; OCH3), 3.91 (s,
(3s):
and zinc powder (2.75 mmol) was evacuated and purged with nitrogen
gas three times. Freshly distilled THF (3.0 mL), o-iodobenzoate
(1.20 mmol), and aldehyde (1.00 mmol) were sequentially added to the
system and the reaction mixture was allowed to stir at 758C for 24 h. The
mixture was filtered through a short Celite and silica-gel pad and washed
with dichloromethane several times. The filtrate was concentrated and
the residue was purified on a silica-gel column by using hexanes/ethyl
acetate as the eluent to afford the cyclization product 3.
3H; OCH ), 6.32 (s, 1H; CH), 7.17 (s, 1H; HC=), 7.25–7.23 (m, 2H; aro-
3
matic H), 7.33–7.32 ppm (m, 3H; aromatic H); 13C NMR (100 MHz,
CDCl3): d=170.40 (C=O), 155.84 (C), 147.82 (C), 147.39 (C), 136.26 (C),
135.61 (C), 129.11 (CH), 128.59 (CH), 127.29 (CH), 120.72 (C), 102.53
(CH), 81.15 (CH), 60.97 (CH3), 60.24 (CH3), 56.38 ppm (CH3); HRMS:
m/z: calcd for C17H16O5: 300.0998; found: 300.0995.
3-(Benzofuran-2-yl)-4,5,6-trimethoxyisobenzofuran-1(3H)one
(3t):
1H NMR (400 MHz, CDCl3): d=3.63 (s, 3H; OCH3), 3.93 (s, 3H;
OCH3), 3.96 (s, 3H; OCH3), 6.50 (s, 1H; CH), 6.83 (s, 1H; HC=), 7.22 (t,
Spectral data for compounds 3a–c, 3h–j and 3s–u are listed bellow. Spec-
tral data of the remaining compounds 3d–g and 3k–r and a copy of the
1H and 13C NMR spectra of all compounds are given in the Supporting
Information.
3J
8.4 Hz, 1H; HC=), 7.40 (d, 3J
3J(H,H)=7.6 Hz, 1H; HC=); 13C NMR (100 MHz, CDCl3): d=169.66
(H,H)=7.6 Hz, 1H; HC=), 7.23 (s, 1H; HC=), 7.29 (t, 3J
ACHRTEUNG ACHTREUNG
AHCTREUNG
AHCTREUNG
3-Phenyl-3H-1-isobenzofuranone (3a): 1H NMR (400 MHz, CDCl3): d=
(C=O), 156.30 (C), 155.17 (C), 150.84 (C), 148.07 (C), 147.25 (C), 131.56
(C), 127.52 (C), 125.26 (CH), 123.10 (CH), 121.52 (CH), 121.44 (C),
111.54 (CH), 107.25 (CH), 102.85 (CH), 73.97 (CH), 61.13 (CH3), 60.58
(CH3), 56.48 ppm (CH3); HRMS: m/z: calcd for C19H16O6: 340.0947;
found: 340.0946.
6.40 (s, 1H; CH), 7.39–7.32 (m, 6H; aromatic H), 7.55 (t, 3J
ACHTREUNG
6.4 Hz, 1H; HC=), 7.65 (t, 3J
ACHTREUNG
ACHTREUNG
3J
(C=O), 149.65 (C), 136.40 (C), 134.29 (CH), 129.33 (CH), 129.27 (CH),
128.95 (CH), 128.44 (C), 126.94 (CH), 125.84 (CH), 122.83 (CH),
82.68 ppm (CH); HRMS: m/z: calcd for C14H10O2: 210.0681; found:
210.0683.
(E)-3-Styrylisobenzofuran-1(3H)one (3u): 1H NMR (400 MHz, CDCl3):
d=6.00 (d, 3J
3J
7.36–7.28 (m, 3H; aromatic H), 7.41–7.38 (m, 2H; aromatic H), 7.45 (d,
3J(H,H)=7.6 Hz, 1H; HC=), 7.55 (t, 3J
(H,H)=7.6 Hz, 1H; HC=), 7.68
(td, 3J(H,H)=8.0 Hz, 4J(H,H)=1.2 Hz, 1H), 7.93 ppm (d, 3J
(H,H)=
(H,H)=8.0 Hz, 1H; CH), 6.12 (dd, 3J
ACHRTEUNG ACHTREUNG
ACHRTEUGN ACHTREUNG
(H,H)=7.6 Hz, 1H; CH=), 6.90 (d, 3J
3-(4-Methylphenyl)-3H-1-isobenzofuranone (3b): 1H NMR (400 MHz,
CDCl3): d=2.35 (s, 3H; CH3), 6.38 (s, 1H; CH), 7.20–7.14 (m, 4H; aro-
A
ACHTREUNG
matic H), 7.31 (d, 3J
A
G
A
N
ACHTREUNG
1H; HC=), 7.63 (t, 3J
T
7.6 Hz, 1H; HC=); 13C NMR (100 MHz, CDCl3): d=170.27 (C=O),
148.78 (C), 135.38(C), 135.19 (CH), 134.20 (CH), 129.43(CH), 128.71
(CH), 128.68 (CH), 126.88 (CH), 125.79 (C), 125.76 (CH), 123.85 (CH),
122.66 (CH), 82.05 ppm (CH); HRMS: m/z: calcd for C16H12O2:
236.0837; found: 236.0838.
6.4 Hz, 1H; HC=); 13C NMR (100 MHz, CDCl3): d=170.54 (C=O),
149.77 (C), 139.28 (C), 134.23 (CH), 133.36 (C), 129.59 (CH), 129.24
(CH), 127.01 (CH), 125.66 (C), 125.52 (CH), 122.82 (CH), 82.73 (CH),
21.18 ppm (CH3); HRMS: m/z calcd for C15H12O2: 224.0837; found:
224.0831.
General procedure for the asymmetric cyclization of 2-iodobenzoate 1
with aldehydes2 : A sealed tube containing [CoI2ACHTRE{UNG (S,S)-dipamp}]
3-[4-(tert-Butyl)phenyl]-1,3-dihydro-1-isobenzofuranone (3c): 1H NMR
(400 MHz, CDCl3): d=1.27 (s, 9H; C
3J(H,H)=8.4 Hz, 2H; HC=), 7.35 (d, 3J
(d, 3J(H,H)=7.6 Hz, 2H; HC=), 7.54 (t, 3J
7.62 (t, 3J(H,H)=7.6 Hz, 1H; HC=), 7.94 ppm (d, 3J
ACHTREUNG
A
(0.050 mmol, 5.0 mol%) and zinc powder (2.75 mmol) was evacuated and
purged with nitrogen gas three times. Freshly distilled THF (3.0 mL), o-
iodobenzoate (1.20 mmol), and aldehyde (1.00 mmol) were sequentially
added to the system and the reaction mixture was allowed to stir at 758C
for 24 h. The mixture was filtered through a short Celite and silica-gel
pad and washed with dichloromethane several times. The filtrate was
concentrated and the residue was purified on a silica-gel column by using
hexanes/ethyl acetate as the eluent to afford the cyclization product 4.
G
ACHTREUNG
G
ACHTREUNG
U
HC=); 13C NMR (100 MHz, CDCl3): d=170.51 (C=O), 152.41 (C),
149.67 (C), 134.17 (CH), 133.25 (C), 129.20 (CH), 126.78 (CH), 125.85
(CH), 125.69 (C), 125.51 (CH), 122.91 (CH), 82.63 (CH), 34.61 (C),
31.16 ppm (CH3); HRMS: m/z: calcd for C18H18O2: 266.1307; found:
266.1312.
Characterization data and chiral HPLC conditions of the obtained opti-
4-(3-Oxo-1,3-dihydro-1-isobenzofuranyl)benzonitrile
(3h):
(H,H)=7.6 Hz, 1H;
(H,H)=7.2 Hz,
1H; HC=), 7.67–7.63 (m, 3H; aromatic H), 7.94 ppm (d, 3J
(H,H)=
1H NMR
cally active phthalides 4a–b are listed bellow. Spectral data of the re-
(400 MHz, CDCl3): d=6.41 (s, 1H; CH), 7.31 (d, 3J
A
maining compounds 4c–e and a copy of the H NMR spectra for all com-
1
HC=), 7.41 (d, 3J
A
G
pounds 4a–e are given in Supporting Information.
(S)-3-Phenylisobenzofuran-1(3H)one (4a): [a]2D7 =+40.3 (c=1.00 in
CH2Cl2) for 84% ee (lit.[15] [a]D20 =+49.5 (c=2.00 in CHCl3) for 98% ee
in the S isomer; lit.[15] [a]D20 =À48.6 (c=2.1 in CHCl3) for 96% ee in the R
AHCTREUNG
7.6 Hz, 1H; HC=); 13C NMR (100 MHz, CDCl3): d=170.00 (C=O),
148.47 (C), 141.62 (C), 134.67 (CH), 132.79 (CH), 129.86 (CH), 127.31
(CH), 125.98 (CH), 125.08 (C), 122.58 (CH), 118.07 (C), 113.13 (C),
81.18 ppm (CH); HRMS: m/z: calcd for C15H9O2N: 235.0633; found:
235.0633.
1
isomer); H NMR (400 MHz, CDCl3): d=6.38 (s, 1H; CH), 7.26–7.23 (m,
2H; aromatic H), 7.31 (d, 3J
N
3
3
3H; aromatic H), 7.53 (t, J
A
3-Biphenyl-4-yl-3H-isobenzofuran-1-one (3i): 1H NMR (400 MHz,
7.2 Hz, 1H; HC=), 7.94 ppm (d, JACHTREUNG
CDCl3): d=6.44 (s, 1H; CH), 7.38–7.32 (m, 4H; aromatic H), 7.42 (t,
ACHTREUNG
4a was isolated in 89% yield and with 84% ee, determined by using
HPLC analysis on a chiral OD-H column, detected at 254 nm. Retention
times in n-hexanes/iPrOH 9:1 were 10.5 min (major) and 13.3 min
(minor) (1.0 mLminÀ1).
3J
3J
A
ACHTREUNG
13C NMR (100 MHz, CDCl3): d=170.70 (C=O), 149.85 (C), 142.56 (C),
4362
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2007, 13, 4356 – 4363