Photochemical studies on 5-methylbicyclo[1.1.1]pentane derivatives: P-orbital overlap controlled enantioselectivity

Article abstract of DOI:10.1002/cjoc.201100083

The first example of the p-orbital overlap controlled enantioselectivity of Norrish type II photocyclization reaction was described. Irradiation of 5-methyl bicyclo[1.1.1]pentanyl ketone with UV in the solid state as well as in the acetonitrile solution afforded the Norrish/Yang photocyclization compound as the sole product. Solid-state asymmetric photochemical studies using ionic chiral auxiliary technique led to the enantioselectivity as high as 60%. The results were rationalized by X-ray single crystal structure. Copyright

Full text of DOI:10.1002/cjoc.201100083

FULL PAPER
DOI: 10.1002/cjoc.201100083
Photochemical Studies on 5-Methylbicyclo[1.1.1]pentane
Derivatives: p-Orbital Overlap Controlled Enantioselectivity
Ma, Manlinga(马满玲) Yang, Chaoa,b(杨超)
Zhao, Guoleia(赵国磊)
Li, Binga(李冰)
Shao, Yutiana(邵玉田)
Xia, Wujiong*,a,b(夏吾炯)
a State Key Laboratory of Urban Water Resource and Environment, Academy of Fundamental and Interdisciplinary
Sciences, Harbin Institute of Technology, Harbin, Heilongjiang 150080
b State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000
The first example of the p-orbital overlap controlled enantioselectivity of Norrish type II photocyclization reac-
tion was described. Irradiation of 5-methyl bicyclo[1.1.1]pentanyl ketone with UV in the solid state as well as in the
acetonitrile solution afforded the Norrish/Yang photocyclization compound as the sole product. Solid-state asym-
metric photochemical studies using ionic chiral auxiliary technique led to the enantioselectivity as high as 60%. The
results were rationalized by X-ray single crystal structure.
Keywords enantioselectivity, p-orbital overlap, solid state, Norrish type II photoreaction, ionic chiral auxiliary
Introduction
what we have achieved in the asymmetric photochemi-
cal as well as the computational studies on 5-methyl
bicyclo[1.1.1]pentane 6.
In the past several years, the approaches for the
solid-state asymmetric synthesis had been well devel-
oped and successfully applied in a variety of photoreac-
tions.[1] Among the methods reported, the solid-state
ionic chiral auxiliary technique developed in Scheffer
group has attracted widespread interest and attention.[2]
In this procedure, the reactant is equipped with a car-
boxylic acid substituent to which an optically pure am-
monium ion (the ionic chiral auxiliary) is attached by
means of a salt bridge. Such salts are required to crys-
tallize in chiral space groups, which provide the asym-
metric environment responsible for chiral induction
when the compounds are photolyzed in the solid state. A
second requirement for the success of the solid-state
ionic chiral auxiliary method of asymmetric synthesis is
that the reactant must crystallize in a conformation fa-
vorable for reaction. For photochemical reactions in-
volving intramolecular hydrogen atom abstraction, this
requires a conformation in which the carbonyl oxygen is
within approximately (2.7±0.2) Å of a γ-hydrogen
atom.[3] In most cases, the differentia in the above dis-
tance between two γ-hydrogen atoms governs the high
enantioselectivity in the solid-state photoreaction.[4]
With our continuous studies on the photoreactions, we
found that 5-methylbicylco[1.1.1]pentane 6 smoothly
undergoes Norrish/Yang type II cyclization reaction
under the irradiation with UV lamp, and speculated that,
in this case, the enantioselectivity could also be con-
trolled by the p-orbital overlap as only one γ-hydrogen
atom existed in the structure. In this paper, we report
4
4
Ar
OH
OH
3'
3'
Ar
1
1
2
3
2
3
Me
Biradicals of ent-6
Me
Biradicals of 6
Results and discussion
The synthesis of 5-methylbicylco[1.1.1]pentane 6
was started from cyclobutyl phenyl ketone 1 as shown
in Scheme 1. According to the reported procedures,[5]
compound 2 was synthesized from starting material 1 in
several steps, which was then reacted with LDA/MeI,
and sequentially reduced with LiAlH4 in Et2O to give
the alcohol 3 in 54% yield (two steps). Alcohol 3 was
oxidized by PCC in CH2Cl2 to afford the aldehyde 4.
Treatment of 4 with the Grignard reagent as used in
previous work at －40 ℃ afforded the alcohol 5 in
48% yield (two steps from 3), which was oxidized by
PCC in CH2Cl2 to give the photoreactant 6 in 85% yield.
Irradiation of compound 6 in acetonitrile through Pyrex
using a 450 W medium-pressure mercury lamp led to
the cyclobutanol compound 7 as a sole photoproduct in
91% yield via an intramolecular Norrish/Yang cycliza-
tion reaction. The formation of 7 was the conversion of
achiral reactant to the chiral product, which is ideal for
asymmetric photochemical studies.
*
E-mail: xiawj@hit.edu.cn
Received June 30, 2011; accepted August 9, 2011.
Chin. J. Chem. 2012, 30, 91—95
© 2012 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
91

Ma et al.
FULL PAPER
Scheme 1 Synthesis of ketone reactants and their photoproducts
O
OH
b
c
a
d
COOCH3
CHO
CH3
OH
CH3
H
CH3
3
COOCH3
1
2
5
4
O
O
O
e
g
f
7
CH3
CH3
COOH
COOCH3
CH3
COO NH3R*
6
8
9
h
OH
a) LDA, MeI, DMPU, THF, -78 oC; LiAlH4, Et2O; b) PCC, CH2Cl2; c) i-PrMgCl, p-IC6H4COOCH3, THF,
- 40 oC; d) PCC, CH2Cl2; e) LiOH, THF/H2O; f) R*NH2; g) hν, solid state, CH2N2; h) hν, CH3CN
COOCH3
CH3
7
HO
H3C
H3C
H
NH2
CH3
NH2
Amines:
H3C
CH2OH
NH2
OH
NH2
H
H
H
NH2
H
NH2
S3
S2
S1
S6
S4
S5
Furthermore, Hyperchem MM3 (version 8.0.3) cal-
culations showed that the C＝O…Hγ distance is 2.60 Å,
which is within the (2.72±0.2) Å range established for
successful γ-hydrogen abstraction in the solid state.
Therefore, 5-methylbicylco[1.1.1]pentane 6 hydrolyzed
with LiOH in THF/H2O to give carboxylic acid 8 in
97% yield, which was then treated with a variety of op-
tically pure amines to form the corresponding ammo-
nium carboxylate salts 9 (Scheme 1). Such salts are re-
quired to crystallize in chiral space groups, which pro-
vide the asymmetric environment responsible for chiral
induction. Crystals of these salts (2—5 mg) were
crushed between two Pyrex microscope slides, sealed in
polyethylene bags under nitrogen, or suspended in 10
mL of hexane, and irradiated with a 450 W medium
pressure mercury lamp.[6] Following photolysis, the
photoproducts were treated with ethereal diazomethane,
and the resulting methyl esters were analyzed by chiral
HPLC to obtain the enantiomeric excess (ee) values and
GC for the conversions. The results of the enantiomeric
excess determinations are summarized in Table 1.
Table 1 Asymmetric studies on the irradiation of salts 9 in the
solid statea
Entry Amine Methodb
Conv.c/%
13
eed/%
60
53
23
10
7
αe
1
2
A
B
B
A
B
A
B
A
B
A
B
A
B
B
S1
S2
38
－
－
3
50
4
28
N.M.f
N.M.f
－
5
64
6
50
18
18
18
12
21
4
7
55
－
8
36
－
S3
S4
S5
S6
9
55
－
10
11
12
13
14
10
－
N.M.f
24
28
21
20
17
＋
32
＋
84
－
Unexpectedly, the photoreaction of salts 9 in the
solid state became rather slow and longer reaction time
had to be employed, which led to the crystals melted
and the breakdown in order of the crystal lattice, result-
ing in low enantioselectivity. Therefore, as shown in
Table 1, the enantiomeric excess values obtained for
photoproduct 7 ranged from low to moderate. Before we
begin to discuss the results observed in the solid state,
there are several geometric parameters for Norrish/Yang
photoreaction which should be introduced. The symbol
d represents the distance between the carbonyl oxygen
and the γ-hydrogen to be abstracted. Ideally these atoms
should lie within 2.72 Å of each other, the sum of their
van der Waals radii. The favorability of the cleavage
a Samples were irradiated through Pyrex using a 450-W Hanovia
medium-pressure mercury lamp. b A: The sample was sandwiched
between two microscope slides; B: the sample was suspended in
c
hexane. Conversion based on GC-MS. d ee analyzed on a Chiral
AS column with V(hexane)∶V(isopropanol)＝99.5∶0.5 as the
e
eluting solvent. Sign of rotation of major enantiomer at sodium
D line. f Not measured.
reaction is gauged through the dihedral angles φ1 and φ4.
The dihedral angle φ1 represents the overlap between
the p-orbital on C(1), the carbonyl carbon, with the
C(2)—C(3) σ-bond that would be fragmented in a
cleavage reaction. Dihedral angle φ4 represents the
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Chin. J. Chem. 2012, 30, 91—95

Photochemical Studies on 5-Methylbicyclo[1.1.1]pentane Derivatives
overlap between the p-orbital on C(4) with the same
C(2)—C(3) bond. For both cases an optimum value of
0° indicates maximum overlap and the ideal geometry
for cleavage. Cyclization reaction is dependent on two
factors. The symbol D is defined as the distance be-
tween the two reacting centres, C(1) and C(4), and
should be less than 3.4 Å, the sum of the van der Waals
radii for two carbon atoms. The second parameter of
interest is β, the dihedral angle formed between the
p-orbital on C(1) and the C(2)—C(4) vector. In the ideal
situation this will be 0°, meaning that the p-orbital is
pointed directly towards the p-orbital on the C(4) carbon,
allowing for closure of the cyclobutane ring. As shown
in Figure 1,[7] d and D are within the sum of the van der
Waals radii. The values of β (6°), φ1 (50°) and φ4 (45°)
suggested that the biradical from 6 has a better geome-
try for cyclization than cleavage. This prediction is in
accordance with the results observed in the solid state,
in which only the cyclization product 7 was obtained.
Although the abstraction distance and other geometric
parameters in this case are as good as or better than
those of dozens of compounds known to react in the
solid state,[8] the results of the solid-state photochemis-
try of salts 9 is puzzled, and intrigues us to do some
theoretical calculations. MM2 (ChemBio3D 11.0) cal-
culations showed that compound 7 has the higher strain
energy than 6 with the difference in strain energy of
131.9 kJ/mol. This might be the reason for unfavorable
formation of 7 in the solid state.
determined on a Fisher-Johns apparatus. High resolution
mass spectra (HRMS) were recorded on a Kratos MS 50
instrument using electron impact (EI) ionization at 70
eV, or chemical ionization (CI) with the ionizing gas
noted, or a Bruker Esquire LC mass spectrometer using
1
electrospray ionization (ESI). H NMR spectra were
obtained at 400 MHz on Bruker AV-400 instrument. 13C
NMR spectra were recorded at 100 MHz.
Synthesis of alcohol 3 To the solution of DIAP
(diisopropylamine, 2.2 mL, 15.7 mmol) in 60 mL of
dried THF precooled at －78 ℃, n-BuLi (n-butyl-
lithium 1.6 mol/L, 9.8 mL, 15.7 mmol) was added
dropwise with stirring. After addition, the mixture was
stirred for 1 h at this temperature. To this solution, 1.9
mL of N,N'-dimethylpropyleneurea (DMPU) was added,
then 1.32 g of 2 dissolved in dried THF (10 mL) was
added slowly. The mixture was stirred at －78 ℃ for 3
h and 3.25 mL of CH3I was added with dropwise. The
mixture was then left to stir overnight and warmed up to
room temperature. After that, saturated ammonium
chloride solution was added, and the solution was
extracted with diethyl ether. The organic layer was
washed with brine, and the solvent was removed in
vacuo after being dried over MgSO4. The residue was
directly used in next steps without further purification.
The residue prepared by the above procedure was
dissolved in anhydrous diethyl ether (50 mL) and added
780 mg (20.5 mmol) of LiAlH4. The mixture was
refluxed overnight. After that, water was added to
destroy the excess LiAlH4. The solution was extracted
with diethyl ether twice and the combined organic layer
was washed with saturated brine before it was dried
over MgSO4. The solvent was removed in vacuo and the
residue was purified by silica gel column chroma-
tography with petroleum ether and diethyl ether (V∶
V＝1∶1) as the eluting solvents to give 0.64 g of 3 as a
colorless oil (54% yield). 1H NMR (CDCl3, 400 MHz) δ:
3.82 (s, 2H), 2.41 (s, 2H), 2.38 (dd, J＝10.9, 3.1 Hz,
1H), 2.33 (dd, J＝10.9, 2.7 Hz, 1H), 1.65 (d, J＝3.1 Hz,
1H), 1.62 (d, J＝2.6 Hz, 1H), 1.32 (s, 3H); 13C NMR
(CDCl3, 100 MHz) δ: 65.2, 62.2, 45.2, 44.8, 38.1, 16.2;
IR (neat) νmax: 3334, 2921, 1473, 1286, 1009, 973, 677
－
＋
1
cm ; MS (70 eV) m/z (%): 113 [M ＋1], 97, 79 (100),
67, 53. HRMS (EI) calcd for C7H12O 112.0888, found
112.0887.
Synthesis of alcohol 5 Alcohol 3 (1.76 g, 15.7
mmol) dissolved in 120 mL of methylene chloride was
added pyridinium chlorochromate (PCC) (4.62 g, 0.02
mol) and Celite (10 g) ground homogeneously in a
mortar. The mixture was stirred at room temperature
overnight, filtered through a silica gel column and
rinsed with diethyl ether. The solvent was then removed
in vacuo, and the residue 4 was used for next step
d/Å
D/Å
β/(°)
ϕ1/(°)
ϕ4/(°)
2.73
2.69
6
50
45
Figure 1 Solid-state conformation of 1-p-tolylethylammonium
salt of keto acid 8.
Experimental
General methods
without purification (GC indicated
approximately 98%).
a purity of
Commercial spectral grade solvents were used for
photochemical experiments unless otherwise stated.
Infrared spectra were recorded on a Perkin-Elmer 1710
Fourier transform spectrometer. Melting points were
To a solution of methyl p-iodobenzoate (6.18 g, 23.5
mmol) in 40 mL of anhydrous THF precooled to －40
℃ was added dropwise isopropylmagnesium chloride
Chin. J. Chem. 2012, 30, 91—95
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93

Ma et al.
FULL PAPER
(2 mol/L, 11.8 mL). After addition, the mixture was
stirred for 1 h at this temperature. To this solution, the
aldehyde 4 dissolved in 10 mL of dry THF was added
slowly. The solution was stirred at －40 ℃ for 4 h.
Saturated ammonium chloride solution (30 mL) was
added quickly and the solution was extracted with
diethyl ether (50 mL×3), and the combined organic
layer washed with saturated brine solution (30 mL×2).
The solvent was removed in vacuo after being dried
over magnesium sulfate, and the residue was purified by
silica gel chromatography (20% petroleum ether/diethyl
ether) to give alcohol 5 as a colorless oil (1.85 g, 48%
126.8, 86.0, 65.7, 54.5, 52.1, 42.3, 39.4, 35.9, 7.8; IR
(neat) νmax: 3606, 2953, 1718, 1437, 1281, 1108, 1074,
－
＋
1
863, 777, 712 cm ; MS (70 eV) m/z (%): 244 [M ],
226, 215, 195 (100), 163, 128, 103, 91, 59; HRMS (EI)
calcd for C15H16O3 244.1099, found 244.1098.
Synthesis of keto-acid 8 To a solution of ketone 6
(730 mg, 3.00 mmol) in THF (20 mL) and H2O (10 mL)
was added LiOH (1.08 g, 45 mmol). The mixture was
stirred at room temperature for 4 h and then diethyl
ether (30 mL) was added. The organic layer was washed
with water (20 mL×3) and the aqueous layers were
combined and acidified with conc. HCl. The solution
was then extracted with diethyl ether (40 mL×4) and
the combined organic layer was washed with water (20
mL×3) and dried over MgSO4. Removal of solvent in
vacuo gave a white solid, which was recrystallized from
methanol to afford keto-acid 8 as a colorless solid (667
1
yield). H NMR (CDCl3, 400 MHz) δ: 7.97 (d, J＝8.3
Hz, 2H), 7.37 (d, J＝8.3 Hz, 2H), 5.62 (brs, 1H), 3.88 (s,
3H), 3.85 (s, 1H), 2.77 (dd, J＝10.9, 3.8 Hz, 1H), 2.64
(d, J＝18 Hz, 1H), 2.44 (d, J＝18 Hz, 1H), 2.30 (dd,
J＝10.9, 3.0 Hz, 1H), 1.83 (d, J＝3.8 Hz, 1H), 1.65 (d,
J＝3.0 Hz, 1H), 1.00 (s, 3H); 13C NMR (CDCl3, 100
MHz) δ: 167.2, 148.8, 131.8, 128.3, 125.7, 71.5, 65.3,
52.0, 44.9, 44.5, 39.8, 38.7, 10.8; IR (neat) νmax: 3606,
2953, 1722, 1702, 1610, 1283, 1018, 851, 774, 733
1
mg, 97% yield), m.p. 137—138 ℃; H NMR (CDCl3,
400 MHz) δ: 8.18 (d, J＝8.4 Hz, 2H), 8.02 (d, J＝8.4
Hz, 2H, CDCl3), 2.97 (s, 3H), 2.38 (dd, J＝10.3, 3.3 Hz,
1H), 1.80 (dd, J＝10.3, 3.5 Hz, 1H), 1.72 (d, J＝3.5 Hz,
1H), 1.70 (d, J＝3.5 Hz, 1H), 1.51 (s, 3H); 13C NMR
(CDCl3, 100 MHz) δ: 205.3, 171.3, 139.7, 132.7, 130.4,
128.7, 70.5, 46.9, 42.5, 41.4, 15.7; IR (KBr) νmax: 3328,
2966, 2552, 1689, 1431, 1234, 1199, 975, 872, 805, 737,
－
＋
1
cm ; MS (70 eV) m/z (%): 247 [M ＋1], 215, 205, 165,
151, 128, 105, 91, 77 (100), 59; HRMS (EI) calcd for
C15H18O3 246.1256, found 246.1254.
Synthesis of ketone 6 To a solution of alcohol 5
(866 mg, 3.52 mmol) in 30 mL of anhydrous methylene
chloride were added PCC (1.52 g, 7.0 mmol) and Celite
(3 g). The mixture was stirred at room temperature
overnight and diethyl ether (20 mL) was added. The
solution was then filtered through a silica gel column
and rinsed with diethyl ether. The solvent was removed
in vacuo and the residue purified by column chroma-
tography (10% petroleum ether/diethyl ether) to give
－
＋
1
704 cm ; MS (ESI) m/z: 229.0 [M －1]. Anal. calcd
for C14H14O3: C 73.03, H 6.13; found C 73.03, H 6.26.
General procedure of synthesis of ammonium
salts 9 To a solution of keto-acid 8 (80 mg, 0.35 mmol)
in diethyl ether (5 mL) was added one equivalent of
optically pure amine. Upon addition, a precipitate
formed immediately. The resulting suspension was
suction filtered to give the salt, which was then
recrystallized from methanol.
1
ketone 6 as a colorless oil (730 mg, 85% yield). H
NMR (CDCl3, 400 MHz) δ: 8.08 (d, J＝8.4 Hz, 2H),
7.96 (d, J＝8.4 Hz, 2H), 3.91 (s, 3H), 2.95 (s, 2H), 2.36
(dd, J＝10.3, 3.4 Hz, 1H), 1.78 (dd, J＝10.3, 3.4 Hz,
1H), 1.70 (d, J＝3.6 Hz, 1H), 1.68 (d, J＝3.4 Hz, 1H),
1.49 (s, 3H); 13C NMR (CDCl3, 100 MHz) δ: 205.2,
166.2, 139.0, 133.5, 129.7, 128.6, 70.5, 52.4, 46.8, 42.5,
41.4, 15.7; IR (neat) νmax: 2979, 2900, 1727, 1437, 1277,
1107, 975, 816, 733 cm ; MS (70 eV) m/z (%): 244
[M＋], 229, 213, 202, 185, 163 (100), 135, 104, 76, 53;
HRMS (EI) calcd for C15H16O3 244.1099, found
244.1096.
(S)-(－)-α-Phenylethylamine salt Yield 99%. m.p.
145—147 ℃ (methanol); 1H NMR (CD3OD, 400 MHz)
δ: 7.89 (d, J＝8.3 Hz, 2H), 7.83 (d, J＝8.3 Hz, 2H),
7.34—7.26 (m, 5H), 4.32 (q, J＝6.8 Hz, 1H), 3.19 (brs,
1H), 2.84 (s, 2H), 2.32 (dd, J＝10.2, 3.3 Hz, 1H), 1.66
(dd, J＝10.2, 3.2 Hz, 1H), 1.61 (d, J＝3.2 Hz, 1H), 1.59
(d, J＝3.3 Hz, 1H), 1.50 (d, J＝6.8 Hz, 3H), 1.40 (s,
3H); 13C NMR (CD3OD, 100 MHz) δ: 207.8, 173.9,
143.4, 140.1, 138.1, 130.4, 130.2, 130.0, 129.4, 127.6,
－
1
72.0, 52.3, 47.5, 43.2, 42.6, 20.9, 16.2; IR (KBr) νmax
:
3851, 2970, 1671, 1521, 1280, 975, 875, 820, 748, 693
－
＋
1
Irradiation of ketone 6 in acetonitrile A solution
of ketone 6 (100 mg, 0.41 mmol) in aceonitrile (80 mL)
was purged with N2 for 15 min and irradiated with 450
W medium mercury pressure lamp under N2 for 24 h.
After irradiation, the solvent was removed in vacuo and
the residue purified by column chromatography (10%
petroleum ether/diethyl ether) to give photoproduct 7
cm ; MS (ESI) m/z: 352 [M ＋1], 335, 253, 105. Anal.
calcd for C22H25NO3: C 75.19, H 7.17, N 3.99; found C
75.46, H 7.18, N 3.93.
(R)-(－)-1-Cyclohexyl ethylamonium salt m.p.
154—155 ℃ (methanol); 1H NMR (CD3OD, 400 MHz)
δ: 7.91 (d, J＝8.4 Hz, 2H), 7.84 (d, J＝8.4 Hz, 2H),
3.19 (brs, 1H), 2.97—2.95 (m, 1H), 2.84 (s, 2H), 2.33
(dd, J＝10.2, 3.3 Hz, 1H), 1.67 (dd, J＝10.2, 3.2 Hz,
1H), 1.61 (d, J＝3.2 Hz, 1H), 1.59 (d, J＝3.3 Hz, 1H),
1.70—1.56 (m, 5H), 1.40 (s, 3H), 1.17—1.15 (m, 2H),
1.13 (d, J＝6.8 Hz, 3H), 1.06—1.05 (m, 1H), 0.96—
0.93 (m, 2H); 13C NMR (CD3OD, 100 MHz) δ: 207.8,
174.0, 143.6, 138.1, 130.4, 129.4, 72.0, 53.4, 47.5, 43.2,
1
(91 mg, 91%) as a colorless oil. H NMR (CDCl3, 400
MHz) δ: 7.96 (d, J＝8.0 Hz, 2H), 7.38 (d, J＝8.0 Hz,
2H), 3.87 (s, 3H), 3.81 (s, 1H), 3.17 (d, J＝17.1 Hz, 1H),
2.35 (d, J＝17.1 Hz, 1H), 2.38 (s, 1H), 2.16 (d, J＝5.6
Hz, 1H), 2.10 (d, J＝5.6 Hz, 1H), 1.32 (s, 3H); 13C
NMR (CDCl3, 100 MHz) δ: 166.9, 145.2, 129.5, 129.1,
94
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Photochemical Studies on 5-Methylbicyclo[1.1.1]pentane Derivatives
42.7, 42.6, 30.0, 28.8, 27.1, 27.0, 26.9, 16.2, 16.0; IR
Hz, 1H), 1.56 (d, J＝3.3 Hz, 1H), 1.46 (d, J＝6.8 Hz,
3H), 1.38 (s, 3H); 13C NMR (CD3OD, 100 MHz) δ:
207.8, 173.9, 143.4, 140.2, 138.1, 136.9, 130.8, 130.4,
129.4, 127.6, 72.0, 52.1, 47.5, 42.6, 43.2, 21.1, 20.8,
16.2; IR (KBr) νmax: 3850, 2979, 2541, 1661, 1526,
1395, 1282, 975, 875, 811, 745, 718 cm ; MS (ESI)
m/z: 366 [M＋＋1], 350, 307, 271, 195, 181, 136. Anal.
calcd for C23H27NO3: C 75.59, H 7.45, N 3.83; found C
75.55, H 7.41, N 3.69.
(KBr) νmax: 3851, 2931, 1670, 1380, 1279, 977, 876,
－
＋
1
819, 742 cm ; MS (ESI) m/z: 358 [M ＋1], 291, 255,
195. Anal. calcd for C22H31NO3: C 73.91, H 8.74, N
3.92; found C 74.20, H 8.79, N 3.80.
－
1
(R)-(－)-1-Amino-indan salt m.p. 167—169 ℃
1
(methanol); H NMR (CD3OD, 400 MHz) δ: 7.89 (d,
J＝8.2 Hz, 2H), 7.83 (d, J＝8.3 Hz, 2H), 7.36 (d, J＝
7.3 Hz, 1H), 7.21—7.15 (m, 3H), 4.66 (dd, J＝7.6, 5.2
Hz, 1H), 3.19 (brs, 1H), 3.02—3.01 (m, 1H), 2.86—
2.85 (m, 1H), 2.83 (s, 2H), 2.46—2.45 (m, 1H), 2.32
(dd, J＝10.2, 3.3 Hz, 1H), 1.97—1.96 (m, 1H), 1.66 (dd,
J＝10.2, 3.2 Hz, 1H), 1.61 (d, J＝3.2 Hz, 1H), 1.59 (d,
J＝3.3 Hz, 1H), 1.40 (s, 3H); 13C NMR (CD3OD, 100
MHz) δ: 207.8, 173.9, 145.4, 143.3, 140.1, 138.1, 130.6,
130.4, 129.4, 128.2, 126.3, 125.5, 72.0, 56.9, 47.5, 43.2,
42.6, 31.8, 31.0, 16.2; IR (KBr) νmax: 3850, 2973, 2893,
Conclusions
In summary, the photochemical behaviours of
5-methylbicylco[1.1.1]pentane 6 in the solid state and
solution were described and discussed. As a first exam-
ple, the p-orbital controlled enantioselectivies of Nor-
rish/Yang photocylclization reaction was conducted by
the asymmetric studies on 6 using ionic chiral auxiliary
method in the solid state.
－
1
2219, 1524, 1386, 977, 821, 755, 740, 711 cm ; MS
(ESI) m/z: 364 [M＋＋1], 348, 285, 253, 231, 195, 181.
Anal. calcd for C23H25NO3: C 76.01, H 6.93, N 3.85;
found C 75.94, H 6.95, N 3.79.
Acknowledgement
(1S,2R)-( － )-cis-1-Amino-2-indanol salt
m.p.
We are grateful to the financial supports from the
National Natural Science Foundation of China (Nos.
20802013, 21002018, 21072038), the Natural Scientific
Research Innovation Foundation in Harbin Institute of
Technology (Nos. 01107866, 01107986) and the Wen-
zhou Science and Technology Program (No.
G20100056).
155—157 ℃ (methanol); 1H NMR (CD3OD, 400 MHz)
δ: 7.90 (d, J＝8.3 Hz, 2H), 7.83 (d, J＝8.3 Hz, 2H),
7.36 (d, J＝7.4 Hz, 1H), 7.23—7.16 (m, 3H), 4.61 (q,
J＝6.0 Hz, 1H), 4.46 (d, J＝5.9 Hz, 1H), 3.19 (brs, 1H),
3.11 (dd, J＝16.3, 6.4 Hz, 1H), 2.91 (dd, J＝16.3, 5.1
Hz, 1H), 2.84 (s, 2H), 2.32 (dd, J＝10.2, 3.4 Hz, 1H),
1.66 (dd, J＝10.2, 3.3 Hz, 1H), 1.61 (d, J＝3.3 Hz, 1H),
1.59 (d, J＝3.4 Hz, 1H), 1.40 (s, 3H); 13C NMR
(CD3OD, 100 MHz) δ: 207.8, 173.9, 143.2, 142.8, 138.2,
130.8, 130.4, 129.4, 128.4, 126.6, 126.2, 72.0, 71.9,
58.6, 47.5, 43.2, 42.6, 40.1, 16.2; IR (KBr) νmax: 3851,
2983, 1667, 1587, 1375, 1279, 977, 808, 756, 741, 704
References and notes
[1] (a) Buschmann, H.; Scharf, H. D.; Hoffmann, N.; Esser, P. Angew.
Chem., Int. Ed. 1991, 30, 477; (b) Inoue, Y. Chem. Rev. 1992, 92,
741; (c) Everitt, S. R. L.; Inoue, Y. In Molecular and Supramolecu-
lar Photochemistry, Vol. 3, Eds.: Ramamurthy, V.; Schanze, K. S.,
Marcel Dekker, New York, 1999, p. 71; (d) Peter, J. P. Adv. Photo-
chem. 1996, 21, 135; (e) Rau, H. Chem. Rev. 1983, 83, 535; (f) Yang,
C.; Xia, W. Asian J. Chem. 2009, 4, 1774; (g) Natarajan, A.; Ng, D.;
Yang, Z.; Garcia-Garibay, M. A. Angew. Chem., Int. Ed. 2007, 46,
6485.
[2] (a) Scheffer, J. R.; Xia, W. Top. Curr. Chem. 2005, 254, 233; (b) Xia,
W.; Yang, C.; Patrick, B. O.; Scheffer, J. R.; Scott, C. J. Am. Chem.
Soc. 2005, 127, 2725; (c) Xia, W.; Scheffer, J. R.; Patrick, B. O.
CrystEngComm 2005, 7, 728.
－
＋
1
cm ; MS (ESI) m/z: 380 [M ＋1], 337, 321, 299, 284,
253, 182, 150, 140. Anal. calcd for C23H25NO4: C 72.80,
H 6.64, N 3.69; found C 73.12, H 6.67, N 3.63.
(1R,2R)-( － )-2-Amino-1-phenyl-1,3-propanediol
salt
m.p. 161 — 163 ℃ (methanol); 1H NMR
(CD3OD, 400 MHz) δ: 7.91 (d, J＝8.4 Hz, 2H), 7.84 (d,
J＝8.6 Hz, 2H), 7.32—7.21 (m, 5H), 4.64 (d, J＝8.7 Hz,
1H), 3.44 (dd, J＝11.7, 3.6 Hz, 1H), 3.31 (dd, J＝11.7,
6.0 Hz, 1H), 3.20—3.19 (m, 1H), 3.17—3.16 (m, 1H),
2.84 (s, 2H), 2.33 (dd, J＝10.3, 3.3 Hz, 1H), 1.67 (dd,
J＝10.3, 3.3 Hz, 1H), 1.61 (d, J＝3.2 Hz, 1H), 1.59 (d,
J＝3.3 Hz, 1H), 1.40 (s, 3H); 13C NMR (CD3OD, 100
MHz) δ: 207.8, 173.9, 143.3, 142.1, 138.1, 130.4, 129.7,
129.5, 129.4, 127.9, 72.3, 72.0, 60.3, 60.0, 47.5, 43.2,
42.6, 16.2; IR (KBr) νmax: 3851, 3240, 1672, 1581, 1396,
[3] Edward, J. T. J. Chem. Educ. 1970, 47, 261.
[4] (a) Yang, C.; Xia, W.; Scheffer, J. R. Tetrahedron 2007, 63, 6791; (b)
Zhao, G.; Yang, C.; Chen, Q.; Jin, J.; Zhang, X.; Zhao, L.; Xia, W.
Tetrahedron 2009, 65, 9952; (c) Xia, W.; Scheffer, J. R.; Boto-
shansky, M.; Kaftory, M. Org. Lett. 2005, 7, 1315.
[5] Sponsler, M. B.; Dougherty, D. A. J. Org. Chem. 1984, 49, 4978.
[6] The reaction became faster when the sample was suspended in hex-
ane. One disadvantage of this method is that the sample could be
slightly soluble in the solvent, resulting in low enantioselectivities.
[7] Crystallographic data for the structures in this paper has been depos-
ited with the Cambridge Crystallographic Data Centre as supple-
mentary publication No. CCDC 773907. Copy of the data can be
obtained, free of charge, on application to CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK, (Fax: +44-(0)1223-336033 or e-mail:
deposit@ccdc.cam.ac. uk).
－
1
1280, 976, 822, 743, 700 cm ; MS (ESI) m/z: 398
[M ＋ ＋ 1], 335, 190, 168, 150. Anal. calcd for
C23H27NO5: C 69.50, H 6.85, N 3.52; found C 69.80, H
6.89, N 3.57.
(S)-(－)-1-p-Tolylethylamine salt m.p. 172—174
℃; 1H NMR (CD3OD, 400 MHz) δ: 7.87 (d, J＝8.5 Hz,
2H), 7.81 (d, J＝8.5 Hz, 2H), 7.18 (d, J＝8.0 Hz, 2H),
7.09 (d, J＝8.0 Hz, 2H), 4.26—4.23 (m, 1H), 3.17 (brs,
1H), 2.81 (s, 3H), 2.30 (dd, J＝10.2, 3.3 Hz, 1H), 2.19
(s, 3H), 1.64 (dd, J＝10.2, 3.3 Hz, 1H), 1.58 (d, J＝3.3
[8] Braga, D.; Chen, S.; Filson, H.; Maini, L.; Netherton, M. R.; Patrick,
B. O.; Scheffer, J. R.; Scott, C.; Xia, W. J. Am. Chem. Soc. 2004,
126, 3511.
(Li, L.)
Chin. J. Chem. 2012, 30, 91—95
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www.cjc.wiley-vch.de
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