Metal–(Pentadentate-Salen) Complexes
FULL PAPER
column chromatography on silica gel (pentane/Et2O, 20:1) to afford the
correspondingepoxide. The ee of the epoxide was determined by HPLC
analysis under the conditions described in the footnotes to Table 1.
trans-3,4-Epoxy-1-phenyl-1-pentyne (30c): 1H NMR (400 MHz, CDCl3):
d=1.39 (d, J=5.3 Hz, 3H), 3.23–3.30 (m, 2H), 7.27–7.34 (m, 3H), 7.42–
7.45 ppm (m, 2H).
3,4-Epoxy-2,2-dimethylchromene (21b): 98% ee, [a]2D7 =+0.62 (c=0.57 in
CHCl3) ([a]2D5 =À0.60 (c=0.93 in CHCl3) for the material of 99% ee[24]);
1H NMR (400 MHz, CDCl3): d=1.25 (s, 3H), 1.58 (s, 3H), 3.49 (d, J=
4.4 Hz, 1H), 3.90 (d, J=4.4 Hz, 1H), 6.81 (d, J=8.4 Hz, 1H), 6.93 (dt,
J=1.2, 7.6 Hz, 1H), 7.24 (dt, J=1.7, 8.1 Hz, 1H), 7.33 ppm (dd, J=1.7,
7.3 Hz, 1H); elemental analysis calcd (%) for C11H12O2 (176.21): C 74.98,
H 6.86; found: C 75.02, H 7.09.
6-Cyano-3,4-epoxy-2,2-dimethylchromene (22b): 99% ee, [a]2D6 =+71.3
(c=0.34 in CHCl3) ([a]2D0 =+53.8 (c=0.16 in CHCl3) for the material of
64% ee[16b]); 1H NMR (400 MHz, CDCl3): d=1.30 (s, 3H), 1.60 (s, 3H),
3.54 (d, J=4.4 Hz, 1H), 3.91 (d, J=4.4 Hz, 1H), 6.87 (d, J=8.4 Hz, 1H),
7.53 (dd, J=2.2, 8.6 Hz, 1H), 7.66 ppm (d, J=2.0 Hz, 1H); elemental
analysis calcd (%) for C12H11NO2 (201.22): C 71.63, H 5.51, N 6.96;
found: C 71.68, H 5.59, N 6.88.
trans-1,2-Epoxy-1-phenylpropane (31b): 31% ee, [a]2D7 =À16.6 (c=0.63 in
CHCl3) ([a]2D5 =À50.4 (c=0.42 in CHCl3) for the material of 86% ee[33]);
1H NMR (400 MHz, CDCl3): d=1.46 (d, J=5.1 Hz, 3H), 3.04 (dq, J=
2.2, 5.1 Hz, 1H), 3.58 (d, J=2.2 Hz, 1H), 7.25–7.36 ppm (m, 5H).
General procedure for asymmetric cyclopropanation: Styrene (115 mL,
1.0 mmol) was added to a solution of [Co(salen)] complex 33 (4.6 mg,
G
5.0 mmol) in toluene (1 mL). tert-Butyl a-diazoacetate (14 mL, 0.1 mmol)
was then added, and the mixture was stirred for 24 h at room tempera-
ture. The mixture was then concentrated in vacuo and the residue was
purified by means of column chromatography on silica gel (hexane/iPr2O,
1:0 to 4:1) to give a 99:1 mixture of the cis- and trans-products in 100%
yield. An aliquot of the mixture was submitted to preparative TLC (silica
gel, hexane/iPr2O, 4:1) to yield the cis-product, the enantiomeric excess
of which was determined by HPLC analysis (97% ee).
6-Bromo-3,4-epoxy-2,2-dimethylchromene (23b): 98% ee, [a]2D5 =+38.0
(c=0.96 in CHCl3); 1H NMR (400 MHz, CDCl3): d=1.17 (s, 3H), 1.49 (s,
3H), 3.41 (d, J=4.4 Hz, 1H), 3.77 (d, J=4.4 Hz, 1H), 6.62 (d, J=8.8 Hz,
1H), 7.25 (dd, J=2.6, 8.6 Hz, 1H), 7.38 ppm (d, J=2.4 Hz, 1H); elemen-
tal analysis calcd (%) for C11H11BrO2 (255.11): C 51.79, H 4.35; found: C
52.02, H 4.47.
3,4-Epoxy-2,2-dimethyl-6-nitrochromene (24b): 99% ee, [a]2D6 =+160.0
(c=0.55 in CHCl3); 1H NMR (400 MHz, CDCl3): d=1.33 (s, 3H), 1.62 (s,
3H), 3.57 (d, J=4.4 Hz, 1H), 3.99 (d, J=4.4 Hz, 1H), 6.89 (d, J=8.8 Hz,
1H), 8.15 (dd, J=3.0, 9.0 Hz, 1H), 8.30 ppm (d, J=2.8 Hz, 1H); elemen-
tal analysis calcd (%) for C11H11NO4 (221.21): C 59.73, H 5.01, N 6.33;
found: C 60.09, H 5.16, N 6.28.
3,4-Epoxy-2,2,6-trimethylchromene (25b): 97% ee, [a]2D6 =+13.2 (c=0.28
in CHCl3); 1H NMR (400 MHz, CDCl3): d=1.23 (s, 3H), 1.57 (s, 3H),
2.28 (s, 3H), 3.47 (d, J=4.4 Hz, 1H), 3.85 (d, J=4.4 Hz, 1H), 6.70 (d, J=
8.0 Hz, 1H), 7.03 (d, J=8.4 Hz, 1H), 7.13 ppm (d, J=2.0 Hz, 1H); ele-
mental analysis calcd (%) for C12H14O2 (190.24): C 75.76, H 7.42; found:
C 76.16, H 7.81.
3,4-Epoxy-6-methoxy-2,2-dimethylchromene (26b): 98% ee, [a]2D6 =+16.4
(c=0.48 in CHCl3); 1H NMR (400 MHz, CDCl3): d=1.22 (s, 3H), 1.56 (s,
3H), 3.46 (d, J=4.4 Hz, 1H), 3.78 (s, 3H), 3.86 (d, J=4.4 Hz, 1H), 6.74
(d, J=9.0 Hz, 1H), 6.80 (dd, J=2.9, 8.8 Hz, 1H), 6.89 ppm (d, J=2.7 Hz,
1H); elemental analysis calcd (%) for C12H14O3 (206.24): C 69.88, H
6.84; found: C 70.10, H 7.22.
G
[a]2D6 =À17.0 (c=0.19 in CHCl3) ([a]D24 =+18.0 (c=0.73 in CHCl3) for the
material of 98% ee[34]); 1H NMR (400 MHz, CDCl3): d=1.13 (s, 9H),
1.24 (ddd, J=5.0, 7.5, 8.5 Hz, 1H), 1.64 (ddd, J=5.0, 5.5, 7.5 Hz, 1H),
1.98 (ddd, J=5.5, 7.5, 8.0 Hz, 1H), 2.53 (ddd, J=7.5, 8.0, 8.5 Hz, 1H),
7.16–7.29 ppm (m, 5H).
tert-Butyl cis-2-(4-methoxyphenyl)cyclopropane-1-carboxylate (36a):
96% ee, [a]2D6 =+3.44 (c=0.18 in CHCl3) ([a]D26 =À3.2 (c=0.85 in CHCl3)
for the material of 96% ee[34]); 1H NMR (400 MHz, CDCl3): d=1.17 (s,
9H), 1.21 (ddd, J=5.0, 7.5, 8.5 Hz, 1H), 1.57 (ddd, J=5.0, 5.5, 7.0 Hz,
1H), 1.93 (ddd, J=5.5, 7.5, 9.0 Hz, 1H), 2.46 (ddd, J=7.0, 8.5, 9.0 Hz,
1H), 3.77 (s, 3H), 6.80 (d, J=8.5 Hz, 2H), 7.18 ppm (d, J=8.5 Hz, 2H).
tert-Butyl
94% ee, [a]2D6 =À6.84 (c=0.18 in CHCl3); 1H NMR (400 MHz, CDCl3):
d=1.16 (s, 9H), 1.20 (m, 1H), 1.59 (m, 1H), 1.94 (ddd, J=5.7, 7.6,
9.3 Hz, 1H), 2.27 (s, 3H), 2.47 (q, J=8.5 Hz, 1H), 7.05 (d, J=8.0 Hz,
2H), 7.15 ppm (d, J=8.0 Hz, 2H); elemental analysis calcd (%) for
C15H20O2 (232.32): C 77.55, H 8.68; found: C 77.27, H 8.69.
tert-Butyl cis-2-(4-nitrophenyl)cyclopropane-1-carboxylate (36c): 93% ee,
[a]2D6 =À35.5 (c=0.10 in CHCl3); H NMR (400 MHz, CDCl3): d=1.18 (s,
9H), 1.37 (ddd, J=5.3, 8.1, 8.2 Hz, 1H), 1.69 (ddd, J=5.5, 5.6, 7.3 Hz,
1H), 2.11 (ddd, J=6.0, 7.6, 9.3 Hz, 1H), 2.56 (q, J=8.5 Hz, 1H), 7.43 (d,
J=8.8 Hz, 2H), 8.13 ppm (d, J=8.8 Hz, 2H); elemental analysis calcd
(%) for C14H17NO4 (263.29): C 63.87, H 6.51, N 5.32; found: C 64.16, H
6.54, N 5.20.
3,4-Epoxyspiro(chroman-2,1’-cyclohexane)(27b)
:
98% ee, [a]2D6 =À11.0
(c=0.68 in CHCl3) ([a]2D4 =+11.2 (c=1.03 in CHCl3) for the material of
90% ee[13b]); 1H NMR (400 MHz, CDCl3): d=1.33–2.07 (m, 10H), 3.49
(d, J=4.4 Hz, 1H), 3.87 (d, J=4.4 Hz, 1H), 6.85 (d, J=8.0 Hz, 1H), 6.92
(dt, J=1.2, 7.4 Hz, 1H), 7.24 (dt, J=1.6, 7.7 Hz, 1H), 7.32 ppm (dd, J=
1.4, 7.4 Hz, 1H); elemental analysis calcd (%) for C14H16O2 (216.28): C
77.75, H 7.46; found: C 77.86, H 7.72.
tert-Butyl
96% ee, [a]2D6 =+4.43 (c=0.18 in CHCl3) ([a]2D0 =+4.4 (c=0.17 in
CHCl3) for the material of 95% ee[19b]); H NMR (400 MHz, CDCl3): d=
1.18 (s, 9H), 1.25 (ddd, J=5.1, 7.8, 8.6 Hz, 1H), 1.59 (ddd, J=5.1, 5.7,
7.3 Hz, 1H), 1.99 (ddd, J=5.7, 7.8, 9.3 Hz, 1H), 2.47 (ddd, J=7.3, 8.6,
9.3 Hz, 1H), 7.19–7.24 ppm (m, 4H).
3,4-Epoxy-2,2,3-trimethylchromene (28b): 97% ee, [a]2D6 =+56.4 (c=0.80
in CHCl3); 1H NMR (400 MHz, CDCl3): d=1.27 (s, 3H), 1.52 (s, 3H),
1.55 (s, 3H), 3.69 (s, 1H), 6.81 (d, J=8.1 Hz, 1H), 6.92 (dt, J=1.2,
7.5 Hz, 1H), 7.23 (dt, J=1.7, 7.6 Hz, 1H), 7.30 ppm (dd, J=1.7, 7.3 Hz,
1H); elemental analysis calcd (%) for C12H14O2 (190.24): C 75.76, H
7.42; found: C 75.81, H 7.54.
tert-Butyl
96% ee, [a]2D6 =À122.5 (c=0.63 in CHCl3); 1H NMR (400 MHz, CDCl3):
d=1.17 (s, 9H), 1.33 (ddd, J=4.9, 7.6, 8.2 Hz, 1H), 1.62 (ddd, J=5.2, 5.4,
7.6 Hz, 1H), 2.13 (ddd, J=5.6, 7.6, 9.1 Hz, 1H), 2.49 (q, J=8.4 Hz, 1H),
7.13–7.20 (m, 2H), 7.26–7.33 ppm (m, 2H); elemental analysis calcd (%)
for C14H17ClO2 (252.74): C 66.53, H 6.78; found: C 66.53, H 6.80.
5,6-Epoxy-6,7,8,9-tetrahydro-5H-benzocycloheptene
(29b):
90% ee,
[a]2D3 =À21.1 (c=0.18 in CHCl3) ([a]D20 =À23.4 (c=0.82 in CHCl3) for the
material of 91% ee[28]); 1H NMR (400 MHz, CDCl3): d=1.52–2.27 (m,
4H), 2.84 (m, 2H), 3.41 (m, 1H), 4.02 (d, J=4.4 Hz, 1H), 7.23–7.59 ppm
(m, 4H); elemental analysis calcd (%) for C11H12O (160.21): C 82.46, H
7.55; found: C 82.26, H 7.78.
tert-Butyl
cis-2-methyl-2-phenylcyclopropane-1-carboxylate
(36 f):
96% ee, [a]2D6 =À48.6 (c=0.10 in CHCl3) ([a]2D4 =À42.1 (c=0.43 in
CHCl3) for the material of 96% ee[34]); 1H NMR (400 MHz, CDCl3): d=
1.07 (dd, J=4.5, 7.5 Hz, 1H), 1.13 (s, 9H), 1.45 (s, 3H), 1.70 (dd, J=4.5,
5.5 Hz, 1H), 1.80 (dd, J=5.5, 7.5 Hz, 1H), 7.16–7.19 ppm (m, 5H).
cis-3,4-Epoxy-1-phenyl-1-pentyne (30b): 1H NMR (400 MHz, CDCl3):
d=1.51 (d, J=5.0 Hz, 3H), 3.25 (dq, J=3.9, 5.0 Hz, 1H), 3.64 (d, J=
3.9 Hz, 1H), 7.28–7.48 ppm (m, 5H); elemental analysis calcd (%) for
C11H10O (158.20): C 83.51, H 6.37; found: C 83.43, H 6.61 (mixture of cis
and trans isomers).
tert-Butyl trans-2-methyl-2-phenylcyclopropane-1-carboxylate (36 f):
97% ee, [a]2D6 =À130.5 (c=0.14 in CHCl3) ([a]2D0 =À133.9 (c=0.10 in
1
CHCl3) for the material of 99% ee[19b]); H NMR (400 MHz, CDCl3): d=
1.33 (dd, J=4.9, 8.3 Hz, 1H), 1.36 (dd, J=4.9, 5.9 Hz, 1H), 1.49 (s, 9H),
1.51 (s, 3H), 1.89 (dd, J=5.9, 8.3 Hz, 1H), 7.18–7.33 ppm (m, 5H).
Chem. Eur. J. 2007, 13, 4849 – 4858
ꢀ 2007 Wiley-VCH VerlagGmbH & Co. KGaA, Weinheim
4857