Novel photoadditions of tertiary amines to the α-position of α,β-unsaturated γ,δ-epoxy nitriles

Article abstract of DOI:10.1039/b110372e

The photoreactions of α,β-unsaturated γ,δ-epoxy nitriles 1,2,13 and 16 with triethylamine give rise to novel 1:1 α-adducts (e.g.,5) efficiently. After treatment with silica gel, the adducts undergo retro-Michael reaction leading to the corresponding α-alk

Full text of DOI:10.1039/b110372e

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Novel photoadditions of tertiary amines to the ꢀ-position of
ꢀ,ꢁ-unsaturated ꢂ,ꢃ-epoxy nitriles
Keitaro Ishii,* Satoshi Hakamada, Mayumi Nagano, Masahiro Noji, Shigeo Sugiyama,
Masashi Kotera and Masanori Sakamoto
1
Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose-shi, Tokyo 204-8588, Japan.
E-mail: ishiikei@my-pharm.ac.jp; Fax: ϩ81 (0)424 958783; Tel: ϩ81 (0)424 958783
Received (in Cambridge, UK) 14th November 2001, Accepted 7th May 2002
First published as an Advance Article on the web 29th May 2002
The photoreactions of α,β-unsaturated γ,δ-epoxy nitriles 1, 2, 13 and 16 with triethylamine give rise to novel 1 : 1
α-adducts (e.g., 5) efficiently. After treatment with silica gel, the adducts undergo retro-Michael reaction leading
to the corresponding α-alkylidenenitrile derivatives (e.g., 3). The epoxy nitrile 1 also reacts with various tertiary
amines to afford α-adducts. The reaction of 1 and the silylamine 24 gives mainly methylene derivative 22 and silylated
compound 25 after treatment with silica gel. The reaction may proceed via single- electron-transfer from the amine
to the excited epoxy nitrile.
Introduction
Results and discussion
Photoinduced electron-transfer reactions have received
considerable interest recently in the discovery of new and
synthetically useful chemical reactions.1 For example, the
photoadditions of tertiary amines to α,β-unsaturated
ketones and esters have been reported to afford 1 : 1 β -adducts
between carbonyl compounds and amines and reduced
compounds.2 Mariano et al. conducted intensive studies
on the photoaddition using α-trimethylsilylamine and on syn-
thetic applications of the photoaddition to N-heterocyclic
compounds.3,4
Photoadditions of epoxy nitriles with TEA
Preparative irradiation of nitrile 1 in TEA. The nitrile (E)-1
was irradiated in TEA with a low-pressure mercury lamp
through a quartz filter (λ = 254 nm) at RT (conversion 51%)
and subsequent silica gel column chromatography yielded
(Z)-1 (6%), α-alkylidenenitrile 3 (26%) and reduced compound
4 (13%) (Scheme 1).† The structure of product 3 was deduced
from the H–H and C–H COSY, phase-sensitive NOESY, and
HMBC spectra. In the HMBC spectrum of 3, the crosspeaks
between H-3 and C(2) (2J), between H-3 and C(1) (3J) and
between H-4 and C(2) (3J) are observed. The appearance of
the crosspeak between H-3 and H-6Ј in the NOESY spectrum
indicates Z orientation at the C(2) double bond.
In a previous communication,5 we have shown that direct
irradiation of α,β-unsaturated γ,δ-epoxy nitrile 16 with
triethylamine (TEA) undergoes novel 1 : 1 α-addition and
subsequent retro-Michael reaction leading to α-alkylidene-
nitrile 3. Similarly, the reaction of 27 gives lactone 6 and
α-alkylidenenitrile 7 (Scheme 1). In this paper we describe the
details of the photoreactions of the epoxy nitriles 1 and 2 with
TEA, reactions of 1 with various tertiary amines, and studies
on the scope and limitation of the addition for epoxy
compounds. Furthermore, the addition of [(trimethylsilyl)-
methyl]diethylamine (TMSA) 24 to the epoxy nitrile 1 is also
investigated.
The characteristic signals of 3 could not be observed in
1
the H NMR spectrum of the crude photoproduct of 1. The
TEA-adduct 5 was separated after basic aluminium oxide
chromatography as a mixture of four diastereomers, which were
treated with silica gel leading to 3 quantitatively. The result
† Yields for compounds throughout the rest of the paper are based on
converted starting material.
Scheme 1 Reagents and conditions: i, λ = 254 nm, Et3N, RT; ii, silica gel.
1592
J. Chem. Soc., Perkin Trans. 1, 2002, 1592–1598
This journal is © The Royal Society of Chemistry 2002
DOI: 10.1039/b110372e

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Scheme 2 Reagents and conditions: i, (EtO)2P(O)CH(Me)CN, NaH, DMF; ii, λ = 254 nm, Et3N, MeCN, RT; iii, silica gel; iv, (EtO)2P(O)CH2CN,
NaH, DMF.
shows that 5 is transformed by acid-catalyzed retro-Michael
reaction to the α-alkylidenenitrile 3.
δC 115.5 and 118.2 due to C(1) and C(2). After treatment of 7
with silica gel, the formation of lactone 6 was not observed.
Therefore, the (E/Z)-configuration of the exocyclic double
bond at C(1Ј) should be E. However, the (E/Z)-configuration at
C(2) for 7 could not be determined.
Preparative irradiation of nitrile 13 with TEA. As the
TEA-adduct 5 could not be separated in pure form, we
attempted to obtain the TEA-adduct 14, stable to silica gel.
The epoxy nitrile 13 was prepared from isophorone oxide in
85% yield (E : Z ≈ 2 : 3) by the Horner–Emmons reaction.
Preparative irradiation of 13 and TEA (30 equiv.) in
acetonitrile with a low-pressure mercury lamp through a quartz
filter (λ = 254 nm) at RT (conversion 65%) gave four adducts
14A–D (20%) and two reduced compounds 15A–B (16%)
(Scheme 2).† One of the adducts 14A was separated in ca. 80%
purity and the structure was assured by its spectral data (see
Experimental section).
The (E/Z)-configuration of 8 was deduced from the chemical
1
shift for 2-H2 and 3-H in the H NMR spectrum; the signals
for 2-H2 (δ 3.49 and 3.71) for (Z)-8 and for 3-H (δ 5.86) for
(E)-8 appear at lower field than those for (E)-8 (δ 3.32) and
for (Z)-8 (δ 5.43), respectively, due to the deshielding effects of
the hydroxy group at C(2Ј).
The mechanism for the formation of the ketone 9 in TEA
solution is not yet clear, because 9 has been afforded by triplet
sensitization reaction of 2 in earlier studies.6,7
We could not isolate the nitriles 11 and 12 (Fig. 1), which
are mainly formed in the photoreaction of 2 in the presence
of TEA (1 equiv.) in acetonitrile.6 In the case of the photo-
reaction of 2 in TEA solution, the formation of 11 and 12 is
suppressed because the SET process from TEA to the excited
state 2* occurs (presumably) faster than the C(γ)–C(δ) bond
cleavage.
Preparative irradiation of nitrile 2 in TEA. The nitrile (E)-2
was irradiated in TEA with a low-pressure mercury lamp
through a quartz filter (λ = 254 nm) at RT (conversion 80%) and
subsequent silica gel chromatography afforded lactone 6 (10%),
α-alkylidenenitrile 7 (6%), reduced compounds (E)-8 (5%) and
(Z)-8 (15%) and ketone 97 (6%) (Scheme 1).†
The structures of 6–8 were determined on the basis of
spectral data. In particular, the 13C NMR spectrum of 6 shows
a characteristic signal at δC 165.9 due to the δ-lactone moiety,
which is also evidenced by the IR band at 1720 cmϪ1. As char-
Preparative irradiation of nitrile 16 with TEA. The nitrile 16
was prepared from trans-4,5-epoxyhexan-3-one in 49% yield
(E : Z ≈ 9 : 2) by the Horner–Emmons reaction. A solution of
the nitrile 16 (E : Z ≈ 3 : 2) and TEA (30 equiv.) in acetonitrile
was irradiated with a low-pressure mercury lamp through
a quartz filter (λ = 254 nm) at RT (conversion 92%) and
subsequent silica gel column chromatography yielded
α-alkylidenenitriles (E)-17 (14%) and (Z)-17 (12%).† The
reduced compound could not be observed.
The (E/Z)-configuration at C-3 for 17 was deduced from
the chemical shift for 3-CH2CH3 in the 13C NMR spectrum;
the signal (δC 20.7) for (E)-17 appears at lower field than that
for (Z)-17 (δC 29.4) due to the steric interactions between 3-Et
and 4-CH(OH)Me. Furthermore, the (E/Z)-configuration at
C-3 was established by the significant NOE enhancements
between 3-CH2CH3 and 5-H (8.5%) for (E)-17 and between
3-CH2CH3 and 4-H (3.5%) for (Z)-17. The (Z)-configuration at
the ethylidene moiety was determined also by the significant
NOE enhancements between 3-CH2CH3 and 2-CH in the ethyl-
idene group (6.6%) for (E)-17 and between 5-H and 2-CH
(2.2%) for Z-17.
1
acteristic signals for the ethylidene moiety of 6, the H NMR
spectrum shows a doublet at δ 1.91 and a quartet-doublet at
δ 6.91, the 13C NMR spectrum has a quartet at δC 13.8 and a
doublet at δC 135.5. Furthermore, the (E/Z)-configuration at
the ethylidene moiety was established by the significant NOE
enhancement (6.9%) between 5-H and Me in the ethylidene
group. The lactone 6 was presumably formed by cyclization of
α-alkylidenenitrile 10 (Fig. 1) possessing the (Z)-configuration
Fig. 1
In the order to test the viability of the reaction, epoxy
ketones 188 and 19‡ and epoxy nitrile 2010 (Fig. 2) were
irradiated in the presence of TEA (30 equiv.) under the
same reaction conditions. However, the TEA-adduct or α-
alkylidenenitrile derivative could not be obtained.
of the exocyclic double bond at C(1Ј) and by subsequent
hydrolysis with silica gel.
Compound 7 could not be isolated in pure form, but the
structure could be presumed by the spectral data of a 1 : 4
1
mixture of 7 and (Z)-8. The H NMR spectrum of 7 shows
a double doublet at δ 2.03 and a quartet-doublet at δ 6.23; the
13C NMR spectrum has a quartet at δC 17.0 and a doublet
at δC 143.2 due to the ethylidene moiety and two singlets at
‡ The irradiations of α,β-epoxy ketones in acetonitrile in the presence
of 5 equiv. of Et3N afford the corresponding β-hydroxy ketones.9
J. Chem. Soc., Perkin Trans. 1, 2002, 1592–1598
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Table 1 Analytical irradiations of 1 with TEAa
Yields (%)†b
Entry
Concentration of TEA (mol dmϪ3) [equiv.]
Solvent
Conversion (%)
3
4
1
2
3
4
5
6
7
0.056 [1]
0.282 [5]
0.564 [10]
1.13 [20]
1.69 [30]
2.26 [40]
neat
0.564 [10]
1.69 [30]
1.69 [30]
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
—
MeCN
PrCN
Hexane
56
72
85
84
95
87
49
99
51
36
trace
8
5 〈6〉c
23 〈3〉
20
22
14
10
14
7
19
31
45
46
27
43
36
22
8d e
9d
10d
12
6
a A 0.0564 mol dmϪ3 solution of 1 (E/Z = 2 : 1) in solvent was irradiated for 1.5 h at RT. b The yields were determined by 1H NMR analysis using
bis(trimethylsilyl)acetylene as internal standard, after stirring of the reaction mixture with silica gel in CHCl3 for 2 h at RT. c Values in angle brackets
are yields the of cyclopropene 21. d Irradiation for 1 h. e With 5 equiv. of PriNH2.
Fig. 2
Analytical irradiations of 1 with TEA. Photoreactions of
nitrile 1 (E/Z = 2 : 1) in acetonitrile containing varying amounts
of TEA (1, 5, 10, 20, 30 and 40 equiv.) or in TEA were
performed, and results are shown in Table 1. The yield of 3
increased with increasing TEA concentration up to 40 equiv. In
Scheme 3
the low concentration range of TEA (entries 1 and 2) the
cyclopropene 216 (Fig. 3) was also formed. For the formation
TEA prompted us to investigate the reactions of nitrile 1 and
other amines. The nitrile 1 was irradiated in the presence of
30 equiv. of tertiary amines (dimethylethylamine, methyldiethyl
amine, tripropylamine, ethyldiisopropylamine, diethylethanol-
amine, 1-methylpyrrolidine, 1-methylpiperidine, tetramethyl-
methanediamine and tetramethylethylenediamine), and the
results are summarized in Table 2. The reactivity for the
addition reaction decreases in the order N–Me ≈ N–Et > N–Pr
> N–Pri substituents owing (presumably) to the steric hindrance
of the α-carbon atom (entries 1–4). The α-carbon atom in cyclic
amines and in diamines has no reactivity (entries 6–9).
Furthermore, the reactions of 1 with a secondary amine
(diethylamine) and a primary amine (butylamine) were also
performed under the same reaction conditions. However, the
corresponding adducts could not be observed.
Fig. 3
of 3 a high concentration of TEA is required. The results may
suggest that TEA functions partially as a base in the reaction.
Thus, isopropylamine (5 equiv.), possessing low electron
donating character, was added to the solution of 1 and TEA
(10 equiv.) in acetonitrile and the solution was irradiated. The
yield of 3 (43%†; entry 8) was similar to that for the reaction
using 30 equiv. of TEA (Entry 5). As the polarity of solvent
decreases, the conversion and the yield of 3 decrease (entries 5,
9 and 10). These results may indicate that a single-electron
transfer (SET) from TEA to the excited epoxy nitrile 1* occurs
(Scheme 3). The resulting ion-radical intermediates (e.g., A) are
transformed into the reduced compound 4 and the adduct 5
via biradical intermediates (e.g., B) in a manner similar to the
reaction of enones and tertiary amines.2 Direct irradiation of
α,β-unsaturated γ,δ-epoxy nitriles and ketones (e.g., 2 and 18)
(λ = 254 nm) in acetonitrile gave mainly the C(γ)–C(δ)
bond-cleaved products (e.g., 12) and the cyclopropene (e.g., 21)
via the carbene intermediate.7,8 Therefore, in the low concen-
tration range of TEA these compounds are formed faster than
are the SET products (e.g., 4 and 5).
The structures of the α-alkylidenenitriles 22 and 23 (Fig. 3)
were determined on the basis of their spectral data. In par-
ticular, the (Z)-orientation at the C(2) double bond in 23 was
1
determined by comparison of the H NMR chemical shifts of
H-3 (δ 6.38) and H2-6Ј (δ 1.86 and 2.00) with those of 3 (δ 6.46
for H-3 and δ 1.87 and 1.98 for H2-6Ј).
Photoaddition of nitrile 1 with TMSA 24
Preparative irradiation. Since the reactions of the nitrile 1 and
tertiary amine had given the α -adducts in moderate yields, the
photoreaction of 1 and TMSA 24,11 which is known as a
stronger electron donor than TEA,§ was investigated. A solution
of the nitrile 1 (E : Z = 2 : 1) and 24 (10 equiv.) in acetonitrile
was irradiated with a low-pressure mercury lamp through
a quartz filter (λ = 254 nm) at RT (conversion 100%) and
subsequent silica gel column chromatography yielded 3 (6%), 4
(23%), 22 (12%) and silylated compound 25 (21%) (Scheme 4).†
Photoadditions of nitrile 1 with various amines
§ Oxidation potentials of TMSA 24 and TEA are 0.57 V and 0.89 V vs.
SCE, respectively.12
The results of the photoreactions of the nitriles 1, 2 and 16 with
1594
J. Chem. Soc., Perkin Trans. 1, 2002, 1592–1598

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Table 2 Irradiations of 1 with various tertiary aminesa
Yields (%)†b
Entry
Amine
Irradiation Time (h)
Conversion (%)
3
22
23
4
1
2
3
4
5
6
7
8
9
EtNMe2
Et2NMe
4.5
5
3
91
94
76
69
89
81
74
90
100
11
22
—
28
41
—
—
—
—
19
13
—
—
—
2
5
1
8
—
—
12
—
—
—
—
—
—
19
20
28
17
10
20
4
Pr3N
Pri2NEt
5
Et2N(CH2)2OH
1-Methylpyrrolidine
1-Methylpiperidine
Me2NCH2NMe2
Me2N(CH2)2NMe2
6.5
3.5
7
2.5
2.5
16
22
a A 0.0564 mol dmϪ3 solution of 1 (E/Z = 2 : 1) in acetonitrile was irradiated (λ = 254 nm) with 30 equiv. of amine at RT. b Isolated yields after silica
gel flash-chromatography.
Table 3 Irradiations of 1 with various concentrations of TMSA 24 in various solventsa
Yields (%)†b
Entry
Concentration of TMSA (mol dmϪ3) [equiv.]
Solvent
Conversion (%)
3
22
25
4
1
2
3
4
5
6
7
8
Ϫ0.175 [5]
0.350 [10]
0.525 [15]
Ϫ1.05 [30]
0.350 [10]
0.350 [10]
0.350 [10]
0.350 [10]
MeCN
MeCN
MeCN
MeCN
0.1%MeOH–MeCN
0.7%MeOH–MeCN
1.4%MeOH–MeCN
10%MeOH–MeCN
41
58
51
53
60
89
81
74
3
5
8
4
8
5
5
4
7
9
10
6
13
11
11
8
10
19
20
12
19
11
10
1
8
11
8
5
7
8
7
6
a A 0.035 mol dmϪ3 solution of 1 (E/Z = 2 : 1) was irradiated (λ = 254 nm) for 0.5 h at RT. b The yields were determined by GLC analysis using
octadecane as an internal standard, after stirring of the reaction mixture with silica gel in CHCl3 for 2 h at RT.
Scheme 4 Reagents and conditions : i, λ = 254 nm, Et2NCH2TMS 24,
MeCN, RT; ii, silica gel, CHCl3, RT.
The structure of product 25 was determined on the basis of
its spectral data. In particular, the (Z)-orientation at the C(2)
1
double bond was determined by comparison of the H NMR
chemical shifts of H-3 (δ 6.57) and H2-6Ј (δ 1.85 and 2.03) with
those of 3.
We also confirmed the reaction of epoxy ketones 188 and 19
and epoxy nitrile 2010 (Fig. 2) in the presence of 10 equiv. of
TMSA 24 under the same reaction conditions. However, the
Scheme 5
TMSA-adducts could not be detected.
olefins 25, 3 and 22. Compound 25 is preferentially formed in
Analytical irradiations
less polar aprotic solvents rather than in polar protic solvents.
The results may show that the deprotonation of Haϩ in C occurs
Photoreactions of nitrile 1 (E/Z = 2 : 1) in acetonitrile contain-
ing varying amounts of TMSA 24 (5, 10, 15 and 30 equiv.)
favorably in a solvent cage (contact-ion-pair).4
In conclusion, the photoreactions of α,β-unsaturated
γ,δ-epoxy nitriles 1, 2, 13 and 16 with TEA afford novel 1 : 1
α-adducts between the nitriles and TEA, and subsequent
retro-Michael reaction gives α-alkylidenenitriles (e.g., 3). The
nitrile 1 also reacts with various tertiary amines and TMSA 24.
The reaction is peculiar to α,β-unsaturated γ,δ-epoxy nitriles
and may proceed via SET from the amine to the excited nitrile.
(entries 1–4) and containing MeOH and 24 (entries 5–8) were
performed, and results are shown in Table 3. The yield of 3, 22
and 25 increased with increasing TMSA 24 concentration up to
0.525 mol dmϪ3. The yield of 25 decreased with increasing
MeOH concentration. The probable reaction mechanism for
the formation of α-alkylidenenitriles 3, 22 and 25 outlined in
Scheme 5 appears to rationalize these results. SET between the
excited nitrile 1* and TMSA 24 results in generation of the
radical-ion-pair (e.g., C). The resulting cation radical 24ϩؒ
Experimental
Mps and bps are uncorrected. Mps were measured with a
ϩ
undergoes α-deprotonation (Ha and Hbϩ) and nucleophile-
assisted desilylation4 leading to the adducts 26 and 27 and 28,
respectively. Finally, retro-Michael reaction gives the respective
Yanaco MP-3 apparatus and bps were measured with a Büchi
J. Chem. Soc., Perkin Trans. 1, 2002, 1592–1598
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Kugel Rohr GKR-50 apparatus. UV spectra were recorded on
a Hitachi 124 spectrometer and IR spectra on a Hitachi 215
spectrometer. NMR spectra were obtained with a JEOL
JNM-EX270 (270 MHz; EX) or a JEOL JNM-GX400 (400
MHz; GX) spectrometer for samples in CDCl3 solution using
tetramethylsilane as internal standard, and J-values are given in
Hz. Mass spectra (MS) and high-resolution MS (HRMS) were
taken on a JEOL JMS-DX302 spectrometer. GLC was carried
out on a Shimadzu GC-14A instrument (flame ionization
detection) and a 30 m × 0.25 mm column of Rascot OV-1 was
used. Column chromatography was performed with Nacalai
silica gel 60 [230–400 mesh (SiO2)] or Merck aluminium oxide
90(basic) [70–230 mesh, activity III (Al2O3)].
of SiO2 (1.0 g) for 2 h at RT. After filtration, 1H NMR analysis
of the reaction mixture showed that 5 was converted to
α-alkylidenenitrile 3 quantitatively.
Preparation of nitrile 13. Diethyl (1-cyanoethyl)phosphonate
(7.64 g, 40.0 mmol) was added dropwise to a suspension of 60%
NaH (1.60 g, 40.0 mmol) in dry DMF (56 cm3) at RT. After
stirring of the mixture for 20 min at RT, isophorone oxide
(5.53 g, 35.9 mmol) was added dropwise and stirring was
continued at Ϫ50 ЊC for 20 min and for 30 min at RT; ice–water
(53 cm3) was then added to the mixture, and the organic phase
was extracted with diethyl ether. The continued extracts were
washed with brine, dried over MgSO4, and concentrated
in vacuo, giving a residue, which was subjected to flash chrom-
atography [SiO2; hexane–ethyl acetate (9 : 1)] to afford the
nitriles (E)-13 (2.18 g, 32%) and (Z)-13 (3.65 g, 53%).
An Eikosha 60 W low-pressure mercury lamp was used for
irradiation. The photolysis solutions were purged with argon
both before and during irradiation.
(E)-2-[4,4,6-Trimethyl-7-oxabicyclo[4.1.0]heptan-2-ylidene]
propiononitrile (E)-13, bp 85 ЊC at 0.25 mmHg (Found : C,
75.22; H, 8.99; N, 7.31. C12H17NO requires C, 75.35; H, 8.96; N,
Photoadditions of nitriles with triethylamine (TEA)
7.32%); νmax (film)/cmϪ1 2210 (C᎐N); δ (EX) 0.83, 0.97 and
Preparative irradiation of nitrile 1 in TEA. A solution of (E)-
16 (700 mg, 3.99 mmol) in TEA (70 cm3) was irradiated with a
low-pressure mercury lamp in a quartz test tube (conversion
51%) for 7 h at RT. After removal of the solvent, flash chrom-
atography [SiO2; hexane–ethyl acetate (4 : 1)] of the residue
afforded (Z)-16 (21.7 mg, 6%), α-alkylidenenitrile 3 (110 mg,
26%) and the alcohol 4 (48.2 mg, 13%).†
᎐
᎐
H
1.39 (9 H, 3 s, 2 × 4Ј-CH3 and 6Ј-CH3), 1.58 (1 H, dd, J 15 and
1, 1- or 5Ј- H), 1.87 (1 H, d, J 15.2, 5Ј-H), 2.08–2.10 (3 H, m
with t character, J 1, 3-H3), 2.24–2.26 (2 H, m, 3Ј-H2) and
3.50 (1 H, s, 5Ј- or 1Ј- 1Ј-H); δC (EX) 15.4, 24.7, 27.2 and 30.2
(4 q, 4 × CH3), 32.3 (s, C-4Ј), 41.1 and 42.9 (2 t, C-3Ј and C-5Ј),
56.8 (d, C-1Ј), 61.8 (s, C-6Ј), 108.3 (s, C-2), 119.0 (s, C-1) and
151.8 (s, C-2Ј); m/z 191 (Mϩ, 100%), 176 (57), 148 (36), 135 (68),
118 (24), 107 (31) and 91 (21).
2-(3-Hydroxy-3,5,5-trimethylcyclohex-1-enyl)isocrotononitrile
3, bp 130 ЊC at 0.22 mmHg (Found: Mϩ, 205.1468. C13H19NO
requires M, 205.1466); λmax (EtOH)/nm 245 (ε/dm3 molϪ1 cmϪ1
(Z)-2-[4,4,6-Trimethyl-7-oxabicyclo[4.1.0]heptan-2-ylidene]
5000); νmax (film)/cmϪ1 3420 (O–H) and 2190 (C᎐N); δ (EX)
᎐
propiononitrile (Z)-13, bp 140 ЊC at 0.9 mmHg (Found : Mϩ,
᎐
H
191.1312. C12H17NO requires M, 191.1310); νmax (film)/cmϪ1
1.02 and 1.05 (6 H, 2 s, 2 × 5Ј CH3), 1.34 (3 H, s, 3Ј-CH3), 1.56
(1 H, d, J 14.2, 4Ј-H), 1.72 (1 H, dd, J 14.2 and 1.0, 4Ј-H),
1.72–1.82 (1 H, br s, OH), 1.87 and 1.98 (2 H, each d, J 16.5,
6Ј-H2), 2.12 (3 H, d, J 7.3, 4-H3), 6.09 (1 H, br s, 2Ј-H) and 6.46
(1 H, q, J 7.3, 3-H); δC (EX) 17.5 (q, C-4), 27.8 and 30.8 (2 q,
2 × 5Ј-CH3), 30.1 (s, C-5Ј), 31.2 (q, 3Ј-CH3), 38.8 (t, C-6Ј), 50.0
(t, C-4Ј), 69.1 (s, C-3Ј), 115.7 (s, C-1), 119.0 (s, C-2), 130.8 (s,
C-1Ј), 132.5 (d, C-2Ј) and 139.9 (d, C-3); m/z 205 (Mϩ, 25%),
190 (100), 163 (17), 148 (19), 139 (17), 134 (11) and 120 (13).
(3-Hydroxy-3,5,5-trimethylcyclohex-1-enyl)acetonitrile 4, bp
110 ЊC at 0.3 mmHg (Found: Mϩ, 179.1333. C11H17NO requires
᎐
2210 (C᎐N); δ (EX) 0.79, 0.98 and 1.40 (9 H, 3 s,2 × 4Ј-CH3
᎐
H
and 6Ј-CH3), 1.58 (1 H, d, J 15, 5Ј-H), 1.88 (1 H, d, J 15, 5Ј-H),
1.97 (3 H, s, 3-H3), 2.03 (2 H, br s, 3Ј-H2) and 3.81 (1 H, s, 1Ј-H);
δC (EX) 16.4, 24.6, 27.0 and 30.7 (4 q, 4 × CH3), 32.5 (s, C-4Ј),
36.6 and 42.9 (2 t, C-3Ј and C-5Ј), 60.6 (d, C-1Ј), 61.7 (s, C-6Ј),
107.9 (s, C-2), 118.9 (s, C-1) and 152.9 (s, C-2Ј); m/z 191 (Mϩ,
100%), 176 (48), 148 (32), 135 (64), 118 (23), 107 (31) and 91
(17).
Preparative irradiation of nitrile 13 with TEA. A solution of
13 (E : Z = 1 : 2) (736 mg, 3.85 mmol) and TEA (11.7 g,
11.6 mmol) in acetonitrile (100 cm3) was irradiated with a low-
pressure mercury lamp in a quartz-test-tube (conversion 65%)
for 2.5 h at RT. After removal of the solvent, flash chrom-
M, 179.1311); νmax (film)/cmϪ1 3420 (O–H) and 2240 (C᎐N);
δH (EX) 1.00 and 1.06 (6 H, 2 s, 2 × 5Ј-CH3), 1.30 (3 H, s,
᎐
᎐
3Ј-CH3), 1.53 and 1.68 (2 H, each d, J 14.2, 4Ј-H2), 1.65–1.75
(1 H, br s,OH), 1.76–1.90 (2 H, m, 6Ј-H2), 3.04 (2 H, br s, 2-H2)
and 5.72 (1 H, d, J 1.0, 2Ј-H); δC (EX) 25. 7 (t, C-2), 27.7, 30.7
and 31.1 (3 q, 2 × 5Ј-CH3 and 3Ј-CH3), 30.4 (s, C-5Ј), 42.1 (t,
C-6Ј), 49.6 (t, C-4Ј), 69.1 (s, C-3Ј), 117.7 (s, C-1), 127.7 (s, C-1Ј),
and 131.1 (d, C-2Ј); m/z 179 (Mϩ, 3%), 164 (100), 139 (36), 123
(27), 100 (20) and 43 (28).
atography [SiO2; hexane–ethyl acetate (4 : 1
1 : 1)] of the
residue afforded adducts 14 (a mixture of four diastereomers,
142 mg, 20%), alcohols 15 [a mixture of two diastereomers
(1 : 1), 77.7 mg, 16%]† and intractable materials (mainly
polymers). Further purification of 14 and 15 by flash
chromatography [SiO2; cyclohexane–ethyl acetate (3 : 2)] gave
14A (contaminated with ca. 20% of 14B) from 14, and 15A
(contaminated with ca. 20% of 15B) and 15B (contaminated
with ca. 30% of 15A) from 15.
Isolation of TEA-adduct 5. A solution of 1 (1.16 g, 6.56
mmol) in TEA (116 cm3) was irradiated with a low-pressure
mercury lamp in a quartz test-tube (conversion 61%) for 8 h at
RT. After removal of the solvent, chromatography [Al2O3;
hexane–ethyl acetate (2 : 1)] of the residue gave a mixture of
four stereoisomers of compound 5 (635 mg, 57%).†
3-(Diethylamino)-2-(3-hydroxy-3,5,5-trimethylcyclohex-1-
enyl)-2-methylbutyronitrile 14A (contaminated with ca. 20% of
14B), an oil (Found : Mϩ Ϫ CH3, 277.2275. C18H32N2O Ϫ CH3
requires M/Z, 277.2280); νmax (film)/cmϪ1 3460 (O–H) and 2220
3-(Diethylamino)-2-(3-hydroxy-3,5,5-trimethylcyclohex-1-
enyl)butyronitrile 5, an oil (Found: Mϩ, 278.2377. C17H30N2O
᎐
(C᎐N); δ (EX) 0.99–1.06 (15 H, m, 4 × CH3 and 4-H3), 1.30
᎐
H
requires M, 278.2358); νmax (film)/cmϪ1 3410 (O–H) and 2230
and 1.50 (6 H, 2 s, 2 × CH3), 1.51–1.90 (5 H, m, OH, 4Ј-H2 and
6Ј-H2), 2.36–2.49 (2 H, m, 2 × NCH ), 2.36–2.49 (3 H, m,
2 × NCH and 3-H) and 5.96–5.98 (1 H, m, 2Ј-H); δC (EX) 10.5,
14.1, 22.9, 27.0, 30.9 and 31.5 (7 q, 2 q at δC 14.1, 7 × CH3), 30.3
(s, C-5Ј), 37.8 and 44.3 (3 t, 2 t at δC 44.3, 2 × NCH2 and C-6Ј),
49.8 (t, C-4Ј), 49.2 (s, C-2), 58.7 (d, C-3), 69.1 (s, C-3Ј), 122.8 (s,
C-1), 129.9 (d, C-2Ј) and 135.6 (s, C-1Ј); m/z 277 (Mϩ Ϫ 15,
0.7%), 191 (0.7), 178 (16), 175 (15), 160 (15), 132 (11), 100 (100),
84 (11) and 56 (12).
᎐
(C᎐N); δH (EX) inter alia 2.33–2.67 (4 H, m, 2 × NCH2), 3.01–
᎐
3.27 (2 H, m, 2- and 3-H) and 5.59 and 5.65 (1 H, 2 br s, 2Ј-H);
δC (EX) inter alia 39.6, 39.7, 40.2 and 40.6 (4 t, C-6Ј), 43.4, 43.5,
46.3 and 46.6 (4 d, C-2), 55.18, 55.22 and 55.5 (3 d, C-3), 69.1
and 69.2 (2 s, C-3Ј), 119.96 and 120.03 (2 s, C-1), 131.3, 131.4,
131.89 and 131.95 (4 s, C-1Ј) and 131.8, 133.0 and 133.1 (3 d,
C-2Ј).
Transformation of 5 into 3. A solution of 5 (51.9 mg, 0.187
2-(3-Hydroxy-3,5,5-trimethylcyclohex-1-enyl)-2-methylprop-
iononitrile 15A (contaminated with ca. 20% of 15B), bp 110 ЊC
mmol) in chloroform (10 cm3) was stirred in the presence
1596
J. Chem. Soc., Perkin Trans. 1, 2002, 1592–1598

View Article Online
at 0.35 mmHg (Found : Mϩ, 193.1470. C12H19NO requires M,
Irradiations of (E )-1 in acetonitrile containing varying
193.1467); νmax (film)/cmϪ1 3520 (O–H) and 2230 (C᎐N);
amounts of TEA. Aliquots of a 0.0564 mol dmϪ3 solution of
nitrile (E)-1 in acetonitrile in the presence of TEA (1, 5, 10, 20,
30 and 40 equiv.) or in TEA were irradiated in quartz test-tubes
under argon for 1.5 h at RT. Yields were determined by
1H NMR (GX) analysis using bis(trimethylsilyl)acetylene as
internal standard, after stirring of the reaction mixture with
SiO2 in CHCl3 for 2 h at RT, and results are shown in Table 1.
᎐
᎐
δH (EX) 1.01, 1.06 and 1.30 (9 H, 3 s, 3Ј-CH3 and 2 × 5Ј-CH3),
1.42 (3 H, d, J 7.3, 3-H3), 1.53 (1 H, d, J 14, 4Ј-H), 1.62 (1 H, br
s, OH), 1.68 (1 H, dt, J 14 and 1.1, 4Ј-H), 1.83 (1 H, dd, J 16.5
and 1.8, 6Ј-H), 1.89 (1 H, d, J 16.5, 6Ј-H), 3.22 (1 H, q, J 7.3,
2-H) and 5.68 (1 H, dd, J 1.8 and 1.1, 2Ј-H); δC (EX) 17.3, 27.4,
30.6 and 31.1 (4 q, 4 × CH3), 30.4 (s, C-5Ј), 32.6 (d, C-2), 40.1 (t,
C-6Ј), 49.9 (d, C-4Ј), 69.1 (s, C-3Ј), 120.9 (s, C-1), 129.8 (d, C-2Ј)
and 133.4 (s, C-1Ј); m/z 193 (Mϩ, 2%), 178 (100), 160 (24), 139
(40), 106 (15), 91 (18) and 77 (12).
2-(3-Hydroxy-3,5,5-trimethylcyclohex-1-enyl)-2-methyl-
propiononitrile 15B (contaminated with ca. 30% of 15A),
an oil; δH (EX) 1.01, 1.05 and 1.30 (9 H, 3 s, 3Ј-CH3 and
2 × 5Ј-CH3), 1.42 (3 H, d, J 7.3, 3-H3), 1.55 (1 H, d, J 13.9,
4Ј-H), 1.69 (1 H, br s, OH), 1.68 (1 H, dd, J 13.5 and 1.1, 4Ј-H),
1.82 and 1.89 (2 H, each d, J 16.9, 6Ј-H2), 3.24 (1 H, q, J 7.3,
2-H) and 5.67–5.69 (1 H, m, 2Ј-H); δC (EX) 17.4, 27.5, 30.6 and
31.1 (4 q, 4 × CH3), 30.4 (s, C-5Ј), 32.6 (d, C-2), 40.0 (t, C-6Ј),
49.9 (d, C-4Ј), 69.1 (s, C-3Ј), 120.8 (s, C-1), 129.8 (d, C-2Ј) and
133.3 (s, C-1Ј).
Preparation of nitrile 16. Diethyl cyanomethylphosphonate
(3.24 g, 18.3 mmol) was added dropwise to a suspension of 60%
NaH (0.73 g, 18.3 mmol) in dry DMF (20 cm3) at 0 ЊC. After
stirring of the mixture for 20 min at 0 ЊC, a solution of trans-
4,5-epoxyhexan-3-one (1.90 g, 16.7 mmol) in DMF (6 cm3) was
added dropwise. After stirring of the mixture for 2 h at RT,
ice–water (24 cm3) was then added to the mixture, the organic
phase was extracted with diethyl ether, and the combined
extracts were subjected to the same work-up as used for the
synthesis of 13. Flash chromatography [SiO2; hexane–benzene–
ethyl acetate (15 : 5 : 1)] afforded the nitriles (E)-16 (875 mg,
40%) and (Z)-16 (195 mg, 9%). (E,4RS,5RS)-3-Ethyl-4,5-
epoxyhex-2-enenitrile (E)-16, bp 80 ЊC at 1 mmHg (Found: Mϩ,
137.0844. C8H11NO requires M, 137.0840); νmax (CHCl3)/cmϪ1
Preparative irradiation of nitrile 2 in TEA. A solution of
(E)-27 (1.22 g, 6.39 mmol) in TEA (122 cm3) was irradiated
with a low-pressure mercury lamp in a quartz test-tube (con-
version 80%) for 50 h at RT. After removal of the solvent,
flash chromatography [SiO2; hexane–ethyl acetate (4 : 1)] of the
residue afforded lactone 6 (110 mg, 10%), α -alkylidenenitrile 7
(63.0 mg, 6%), alcohols (E)-8 (54.0 mg, 5%) and (Z)-8 (147 mg,
15%) and ketone 97 (58.2 mg, 6%).†
᎐
2220 (C᎐N) and 1620 (C᎐C); δ (GX) 1.17 (3 H, t, J 7.7,
᎐
᎐
H
3-CH2CH3), 1.40 (3 H, d, J 5.1, 6-H3), 2.40 (1 H, dd, J 17 and
7.7, 3-CH), 2.53 (1 H, dd, J 17 and 7.7, 3-CH), 2.80 (1 H, qd,
J 5.1 and 1.8, 5-H), 3.14–3.15 (1 H, m with d-character, J 1, 4-
H) and 5.33 (1 H, s, 2-H); δC (EX) 12.9 and 17.7 (2 q, 2 × CH3),
25.5 (t, 3-CH2), 58.5 and 58.6 (2 d, C-4 and C-5), 93.8 (s, C-2),
116.4 (s, C-1) and 165.4 (s, C-3); m/z 137 (Mϩ, 21%), 122 (100),
108 (21), 94 (76), 79 (28) and 66 (69). (Z,4RS,5RS)-3-Ethyl-4,5-
epoxyhex-2-enenitrile (Z)-16 [contaminated with ca. 20% of
(E)-16], an oil; δH (GX) 1.07 (3 H, t, J 7.3, 3-CH2CH3), 1.43
(3 H, d, J 5.1, 6-H3), 1.98 (1 H, dqd, J 17, 7.3 and 2, 3-CH), 2.13
(1 H, dqd, J 17, 7.3 and 1.8, 3-CH), 3.09 (1 H, qd, J 5.1 and 2.2,
5-H), 3.64–3.65 (1 H, m with d-character, J 1, 4-H) and 5.32
(1 H, s, 2-H); δC (EX) 11.6 and 17.6 (2 q, 2 × CH3), 23.6 (t,
3-CH2), 54.8 and 58.4 (2 d, C-4 and C-5), 96.5 (s, C-2), 116.1 (s,
C-1) and 165.5 (s, C-3).
4-(E)-Ethylidene-1,7,7-trimethyl-2-oxabicyclo[4.4.0]dec-5-
en-3-one 6, bp 125 ЊC at 0.2 mmHg (Found : Mϩ, 220.1460.
C14H20O2 requires M, 220.1463); νmax (film)/cmϪ1 1720 (C᎐O);
᎐
δH (EX) 1.18, 1.26 and 1.56 (9 H, 3 s, 1-CH3 and 2 × 7-CH3),
1.39–2.08 (6 H, m, 8-, 9-and 10-H2), 1.91 (3 H, d, J 7.6,
4 = CHCH3), 6.35 (1 H, s, 5-H) and 6.91 (1 H, qd, J 7.6 and 1.0,
4 = CH); δC (EX) 13.8 (q, 4 = CHCH3), 19.1 (t, C-9), 29.5, 29.8
and 30.9 (3 q, 3 × CH3), 36.3 (s, C-7), 39.5 and 39.9 (2 t, C-8 and
C-10), 83.7 (s, C-1), 114.0 (d, C-5), 124.1 (s, C-4), 135.5 (d,
4 = CH), 149.3 (s, C-6) and 165.9 (s, C-3); m/z 220 (Mϩ, 89%),
205 (43), 180 (22), 150 (100), 100 (47) and 96 (18).
Preparative irradiation of nitrile 16 with TEA. A solution of
16 (E : Z = 3 : 2) (1.10 g, 8.02 mmol) and TEA (24.3 g,
241 mmol) in acetonitrile (76.5 cm3) was irradiated with a
low-pressure mercury lamp in a quartz test-tube (conversion
92%) for 7 h at RT. After removal of the solvent, a solution of
the residue in CHCl3 (110 cm3) was stirred in the presence
of SiO2 (22 g) for 2 h at RT. After filtration, the filtrate was
evaporated to give a residue, which was subjected to flash
chromatography [SiO2; hexane–ethyl acetate (4 : 1)] to afford
(E)-17 (165 mg, 14%), (Z)-17 (145 mg, 12%) and intractable
materials (mainly polymers).† (E)-3-Ethyl-2-[(Z)-ethylidene]-
5-hydroxyhex-3-enenitrile (E)-17 [contaminated with ca. 45%
of (Z)-17], an oil; δH (GX) 1.03 (3 H, t, J 7.3, 3-CH2CH3), 1.32
(3 H, d, J 6.3, 6-H3), 1.91 (1 H, br s, OH), 2.10 (3 H, d, J 7.1,
2-CHCH3), 2.30 and 2.37 (2 H, each dq, J 14.3 and 7.3, 3-CH2),
4.66 (1 H, dq, J 8.6 and 6.3, 5-H), 5.88 (1 H, d, J 8.6, 4-H) and
6.50 (1 H, q, J 7.1, 2-CH); δC (GX) 13.7, 17.6 and 23.8 (3 q,
3 × CH3), 20.7 (t, 3-CH2), 64.5 (d, C-5), 116.0 and 118.4 (2 s,
C-2 and C-1), 134.6 (d, C-4), 136.2 (s, C-3) and 140.4 (d, 2-CH).
(Z)-3-Ethyl-2-[(Z)-ethylidene]-5-hydroxyhex-3-enenitrile (Z)-
17, an oil (Found: Mϩ, 165.1154. C10H15NO requires M,
2-[(E)-2-Hydroxy-2,6,6-trimethylcyclohexylidenemethyl]but-
2-enenitrile 7 [contaminated with ca. 80% of (Z)-8], an oil;
δH (EX) inter alia 2.03 (3 H, dd, J 7.3 and 1.3, 4-H3), 5.87 (1 H,
br s, 2-CH᎐C) and 6.23 (1 H, qd, J 7.3 and 1.7, 3-H); δ (EX)
᎐
C
inter alia 17.0 (q, C-4), 74.3 (s, C-2Ј), 115.5 and 118.2 (2 s, C-1
and C-2), 116.7 (d, 2-CH᎐C), 143.2 (d, C-3) and 157.2 (s, C-1Ј).
᎐
3-[(E)-2-Hydroxy-2,6,6-trimethylcyclohexylidene]propiono-
nitrile (E)-8, bp 120 ЊC at 0.1 mmHg (Found: Mϩ, 193.1458.
C12H19NO requires M, 193.1467); νmax (film)/cmϪ1 3430 (O–H)
᎐
and 2240 (C᎐N); δH (EX) 1.22, 1.29 and 1.39 (9 H, 3 s, 2Ј-CH3
᎐
and 2 × 6Ј-CH3), 1.39–1.82 (7 H, m, 3Ј-, 4Ј- and 5Ј-H2 and OH),
3.32 (2 H, d, J 7.3, 2-H2) and 5.86 (1 H, t, J 7.3, 3-H); δC (EX)
18.1 and 18.2 (2 t, C-2 and C-4Ј), 29.6, 30.7 and 31.4 (3 q,
2 × 6Ј-CH3 and 2Ј-CH3), 36.2 (s, C-6Ј), 39.1 and 40.9 (2 t, C-3Ј
and C-5Ј), 73.8 (s, C-2Ј), 112.6 (d, C-3), 118.9 (s, C-1) and 156.3
(d, C-1Ј); m/z 193 (Mϩ, 10%), 178 (70), 160 (20), 153 (100), 135
(37), 108 (36), 100 (44), 95 (30) and 43 (33).
3-[(Z)-2-Hydroxy-2,6,6-trimethylcyclohexylidene]propiono-
nitrile (Z)-8, bp 120 ЊC at 0.15 mmHg (Found: Mϩ, 193.1468.
C12H19NO requires M, 193.1467); νmax (film)/cmϪ1 3420 (O–H)
and 2240 (C᎐N); δH (EX) 1.09 and 1.16 (6 H, 2 s, 2 × 6Ј-CH3),
165.1083); νmax (CHCl3)/cmϪ1 3370 (C–O) and 2180 (C᎐N);
᎐
᎐
᎐
᎐
1.44 (3 H, s, 2Ј-CH3), 1.40–1.89 (7 H, m, 3Ј-, 4Ј- and 5Ј-H2 and
OH), 3.49 (1 H, dd, J 18.1 and 7.6, 2-H), 3.71 (1 H, dd, J 18.1
and 6.9, 2-H) and 5.43 (1 H, m with t-character, J 7, 3-H);
δC (EX) 18.1 and 19.2 (2 t, C-2 and C-4Ј), 29.2, 31.4 and 31.9
(3 q, 2 × 6Ј-CH3 and 2Ј-CH3), 37.5 (s, C-6Ј), 39.6 and 43.9 (2 t,
C-3Ј and C-5Ј), 74.2 (s, C-2Ј), 113.6 (d, C-3), 120.2 (s, C-1) and
156.3 (d, C-1Ј); m/z 193 (Mϩ, 20%), 178 (100), 160 (61), 153
(90), 119 (39), 95 (49), 81 (40) and 43 (90).
δH (GX) 1.03 (3 H, t, J 7.6, 3-CH2CH3), 1.29 (3 H, d, J 6.4,
6-H3), 1.58 (1 H, br s, OH), 2.11 (3 H, d, J 7.0, 2-CHCH3), 2.23
(2 H, qd, J 7.6 and 1.2, 3-CH2), 4.52 (1 H, dq, J 9.2 and 6.4,
5-H), 5.45 (1 H, d, J 9.2, 4-H) and 6.38 (1 H, q, J 7.0, 2-CH);
δC (GX) 12.5, 17.4 and 23.7 (3 q, 3 × CH3), 29.4 (t, 3-CH2), 64.8
(d, C-5), 114.7 and 116.5 (2 s, C-2 and C-1), 133.1 (d, C-4),
137.4 (s, C-3) and 146.0 (d, 2-CH); m/z 165 (Mϩ, 13%), 151 (41),
147 (9), 136 (33), 123 (100), 108 (30), 95 (25) and 77 (23).
J. Chem. Soc., Perkin Trans. 1, 2002, 1592–1598
1597

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Photoadditions of nitrile 1 with various amines
C-3); m/z 263 (Mϩ, 7%), 248 (18), 145 (86), 130 (100), 203 (17),
139 (24), 84 (16) and 73 (62).
By analogy with the photoreaction of 16 with TEA, the nitrile 1
was irradiated with 30 equiv. of an amine in acetonitrile, afford-
ing the corresponding adducts. The results are summarized in
Table 2.
Irradiations with various concentrations of TMSA 24 in
various solvents. Aliquots of a 0.0564 mol dmϪ3 solution of
nitrile 1 (E/Z = 2 : 1) in acetonitrile containing varying
amounts of TMSA 24 (5, 10, 15 and 30 equiv.) and MeOH were
irradiated in quartz test-tubes under argon for 0.5 h at RT.
Yields were determined by GLC analysis using octadecane as
internal standard, after stirring of reaction mixture with SiO2 in
CHCl3 for 2 h at RT, and results are shown in Table 3.
2-(3-Hydroxy-3,5,5-trimethylcyclohex-1-enyl)acrylonitrile
22, bp 150 ЊC at 0.3 mmHg (decomposition) (Found: Mϩ,
191.1309. C12H17NO requires M, 191.1310); νmax (CHCl3)/cmϪ1
᎐
3590, 3470 (O–H) and 2220 (C᎐N); δ (EX) 1.03 and 1.06 (6 H,
᎐
H
2 s, 2 × 5Ј-CH3), 1.36 (3 H, s, 3Ј-CH3), 1.57 and 1.73 (2 H, each
d, J 14.2, 4Ј-H2), 1.66 (1 H, br s, OH), 1.87 (1 H, dd, J 16.5 and
2, 6Ј-H), 2.01 (1 H, d, J 16.5, 6Ј-H), 5.88 and 5.93 (2 H, each s,
3-H2) and 6.22 (1 H, br s, 2Ј-H); δC (EX) 27.8, 30.9 and 31.1
(3 q, 3 × CH3), 30.1 (s, C-5Ј), 38.0 (t, C-6Ј), 49.5 (t, C-4Ј), 69.1
(s, C-3Ј), 117.1 (s, C-1), 124.6 (s, C-2), 126.9 (t, C-3), 130.8 (s,
C-1Ј) and 135.3 (d, C-2Ј); m/z 191 (Mϩ, 38%), 176 (100), 149
(27), 139 (41), 134 (29), 120 (26) and 106 (23).
Acknowledgements
We thank the staff of the Analysis Center of Meiji Pharm-
aceutical University for performing the elemental analysis and
measurements of GX-NMR (Miss S. Yoshioka) and mass
spectra (Miss T. Koseki). We are also grateful to Miss A. Iizuka
for her technical assistance. This work was partially supported
by a Special Grant from Meiji Pharmaceutical University
(Z)-2-(3-Hydroxy-3,5,5-trimethylcyclohex-1-enyl)pent-2-
enenitrile 23, bp 130 ЊC at 0.15 mmHg (Found: Mϩ, 219.1620.
C14H21NO requires M, 219.1623); νmax (film)/cmϪ1 3410 (O–H)
᎐
and 2220 (C᎐N); δH (EX) 1.02 and 1.06 (6 H, 2 s, 2 × 5Ј-CH3),
᎐
References
1.12 (3 H, t, J 7.6, 5-H3), 1.34 (3 H, s, 3Ј-CH3), 1.56 (1 H, d,
J 14.2, 4Ј-H), 1.72 (1 H, m with dt-character, J 14.2 and 1, 4Ј-
H), 1.75 (1 H, br s, OH), 1.86 (1 H, dd, J 16.5 and 1.7, 6Ј-H),
2.00 (1 H, m with dt-character, J 16.5 and 1, 6Ј-H), 2.50 (2 H,
quintet, J 7.6, 4-H2), 6.09 (1 H, br s, 2Ј-H) and 6.38 (1 H, t,
J 7.6, 3-H); δC (EX) 13.2 (q, C-5), 25.3 (t, C-4), 27.9, 30.9 and
31.3 (3 q, 3 × CH3), 30.1 (s, C-5Ј), 38.8 (t, C-6Ј), 49.6 (t, C-4Ј),
69.1 (s, C-3Ј), 115.7 and 117.3 (2 s, C-1 and C-2), 130.8 (s, C-1Ј),
132.8 (d, C-2Ј) and 146.5 (d, C-3); m/z 219 (Mϩ, 31%), 204
(100), 177 (16), 148 (9), 139 (20) and 134 (10).
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in Advances in Electron Transfer Chemistry, ed. P. S. Mariano, JAI
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in Electron Transfer Chemistry, ed. P. S. Mariano, JAI Press,
Stamford, 1996, vol. 5, p. 141.
Photoaddition of nitrile 1 with TMSA 24
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Preparative irradiation. A solution of 1 (E : Z = 2 : 1) (470 mg,
2.65 mmol) and TMSA 24 (4.22 g, 26.5 mmol) in acetonitrile
(71.6 cm3) was irradiated with a low-pressure mercury lamp in a
quartz test-tube (conversion 100%) for 4 h at RT. After removal
of the solvent, a solution of the residue in CHCl3 (97 cm3) was
stirred in the presence of silica gel (1.9 g) for 2 h at RT. After
filtration, the filtrate was evaporated to give the residue, which
was subjected to flash chromatography [SiO2; benzene–ethyl
acetate (9 : 1)] to afford 3 (6%), 4 (23%), 22 (12%) and 25 (21%).†
(Z)-2-(3-Hydroxy-3,5,5-trimethylcyclohex-1-enyl)-3-(trimeth-
ylsilyl)acrylonitrile 25, mp 87–89 ЊC (Found: Mϩ, 263.1696.
C15H25NOSi requires M, 263.1705); νmax (film)/cmϪ1 3440
᎐
(O–H) and 2220 (C᎐N); δ (EX) 0.29 [9 H, s, Si(CH3)3], 1.04
᎐
H
and 1.06 (6 H, 2 s, 2 × 5Ј-CH3), 1.36 (3 H, s, 3Ј-CH3), 1.56 and
1.73 (2 H, each d, J 14.2, 4Ј-H2), 1.70 (1 H, br s, OH), 1.85 (1 H,
dd, J 16.5 and 2.0, 6Ј-H), 2.03 (1 H, m with d-character, J 16.5,
6Ј-H), 6.24 (1 H, br s, 2Ј-H) and 6.57 (1 H, s, 3-H); δC (EX)
Ϫ1.38 [3 q, Si(CH3)3], 27.9, 30.2 and 30.9 (3 q, 3 × CH3), 30.2 (s,
C-5Ј), 38.4 (t, C-6Ј), 49.6 (t, C-4Ј), 69.3 (s, C-3Ј), 117.2 (s, C-1),
129.6 and 130.8 (2 s, C-2 and C-1Ј), 134.4 (d, C-2Ј) and 145.5 (d,
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1598
J. Chem. Soc., Perkin Trans. 1, 2002, 1592–1598