Photoinduced Electron Transfer Reactions of α-Cyclopropyl- And α-Epoxy Ketones. Tandem Fragmentation-Cyclization to Bi-, Tri-, and Spirocyclic Ketones

Article abstract of DOI:10.1021/jo961015b

Reductive photoinduced electron transfer (PET) reactions have been performed with various bicyclic a-cyclopropyl-substituted ketones and tertiary amines. The reaction resulted in a regioselective cleavage of one cyclopropyl bond under formation of an exocyclic radical with an endocyclic enolate unit. In the case of bicyclic ketones with an unsaturated side chain, various bicyclic, spirocyclic, and tricyclic products are accessible via radical cyclization, depending on the position of the alkenyl substituent. In addition to triethylamine, W-silylated amines have also been used as electron donors, leading to a variety of compounds, among them are silylated fragmentation products, indicating that a proton is transferred from not only the amine radical cation but also the cationic silyl group. The intramolecular Paternoe-Buechi reaction has also been studied for cyclopropane derivatives of the jasmone type leading to tetracyclic oxetanes. Finally, α-epoxy-substituted ketones have been investigated under PET conditions, yielding ring-opened products.

Full text of DOI:10.1021/jo961015b

J . Org. Chem. 1996, 61, 8885-8896
8885
P h otoin d u ced Electr on Tr a n sfer Rea ction s of r-Cyclop r op yl- a n d
r-Ep oxy Keton es. Ta n d em F r a gm en ta tion -Cycliza tion to Bi-, Tr i-,
a n d Sp ir ocyclic Keton es
Thorsten Kirschberg† and J ochen Mattay*
Institut fu¨r Organische Chemie der Universita¨t Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany
Received May 31, 1996X
Reductive photoinduced electron transfer (PET) reactions have been performed with various bicyclic
R-cyclopropyl-substituted ketones and tertiary amines. The reaction resulted in a regioselective
cleavage of one cyclopropyl bond under formation of an exocyclic radical with an endocyclic enolate
unit. In the case of bicyclic ketones with an unsaturated side chain, various bicyclic, spirocyclic,
and tricyclic products are accessible via radical cyclization, depending on the position of the alkenyl
substituent. In addition to triethylamine, N-silylated amines have also been used as electron donors,
leading to a variety of compounds, among them are silylated fragmentation products, indicating
that a proton is transferred from not only the amine radical cation but also the cationic silyl group.
The intramolecular Paterno´-Bu¨chi reaction has also been studied for cyclopropane derivatives of
the jasmone type leading to tetracyclic oxetanes. Finally, R-epoxy-substituted ketones have been
investigated under PET conditions, yielding ring-opened products.
Sch em e 1
Sch em e 2
In tr od u ction
The search for synthetic, useful photoinduced electron
transfer (PET) reactions is continuously increasing in
organic synthesis.1-7 The often observed high selectivity
can be achieved by activating only one reactant under
mild conditions. Starting from neutral compounds, the
PET reaction leads to the formation of a radical ion pair
(Scheme 1) of which the fate depends on the rate of back
electron transfer, the solvent, the added salts, and the
spin multiplicity.8
Earlier examples were concerned with the photoreac-
tions of ketones with amines9-12 and alkenes,13 leading
to the ketyl radical anion and to the corresponding donor
radical cation. Alternatively, ketyl radical anions can
also be formed by various methods like electrochemical
reduction,14 dissolved sodium or potassium in liquid
ammonia,15 naphthalene sodium16,17 or samarium diio-
dide.18 Due to our general interest in PET processes3 and
starting from PET reductive cleavage and cyclization
reactions of cyclohexenones,19 we have recently reported
a preliminary investigation of R-cyclopropyl-substituted
ketones.3d,20 The concept of this new PET reductive
cleavage reaction19 is shown in Scheme 2. The driving
force is gained from the fast cyclopropylcarbinyl-ho-
moallyl rearrangement21,22 (k ) 108 s-1) and the genera-
tion of an enolate, altogether leading to a distonic radical
anion.
* To whom correspondence should be addressed. Fax: +49-431-880-
7410. E-mail: mattay@oc.uni-kiel.de.
† Taken in part from Ph.D. Thesis (University of Mu¨nster). Current
address: Department of Chemistry, Stanford University, Stanford, CA
94305.
X Abstract published in Advance ACS Abstracts, November 1, 1996.
(1) Mattes, S. L.; Farid, S. Org. Photochem. 1983, 6, 233.
(2) Mariano, P. S. Synthetic Organic Photochemistry; Horspool, W.
M., Ed.; Plenum Press: New York, 1984; p 145.
(3) (a) Mattay, J . Angew. Chem., Int. Ed. Engl. 1987, 26, 825. (b)
Mattay, J . Synthesis 1989, 233. (c) Mu¨ller, F.; Mattay, J . Chem. Rev.
1993, 93, 99. (d) Albrecht, A.; Averdung, J .; Bischof, E. W.; Heidbreder,
A.; Kirschberg, Th.; Mu¨ller, F.; Mattay, J . J . Photochem. Photobiol., A
1994, 82, 219. (e) Hintz, S.; Heidbreder, A.; Mattay, J . Top. Curr. Chem.
1996, 177, 77.
Linking I to an appropriate unsaturated side chain a
cyclization via the radical center of III would be feasible
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fer; VCH Publishers: New York, 1993; p 1.
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S0022-3263(96)01015-8 CCC: $12.00 © 1996 American Chemical Society

8886 J . Org. Chem., Vol. 61, No. 25, 1996
Kirschberg and Mattay
Sch em e 3
as a secondary step. A favored process could be the well-
known 5-exo cyclization of 5-hexenyl radicals.23-26 Due
to the position of the unsaturated side chain, both
annealated and spirocyclic ring systems should be ac-
cessible. In addition, the enolate of the radical anion III
could be trapped by an oxophile like TMS+ to yield silyl
enol ethers. For this purpose, N-silylated amines as
donors were also tested. The radical cations of these
compounds are supposed to transfer the cationic tri-
methylsilyl group to the carbonyl oxygen. Furthermore
we investigated R-epoxy-substituted ketones of which the
PET chemistry is not yet completely understood. Analo-
gous to the cyclopropane system, the formation of an
enolate beside an oxygen-centered radical is expected.27
Alternatively, an R-acyl radical beside a negatively
charged former epoxy oxygen might be formed.28
Ta ble 1. Rin g Op en in g of Cyclop r op yl Keton es by
Red u ctive P ET Rea ction s
Resu lts a n d Discu ssion
Clea va ge of r-Cyclop r op yl Keton es by Red u ctive
P ET. Since our main interest was to perform intramo-
lecular cyclization reactions of the intermediate III, it
was important first to determine the regioselectivity of
the cyclopropyl bond cleavage if the R-cyclopropyl system
is incorporated into a bi- or polycyclic system. For this
purpose, compounds 1-3 were synthesized. For 1 and
2 we used Corey’s cyclopropanization method29 starting
from the corresponding enones. Compound 3 was syn-
thesized according to the methods reported in the litera-
ture from cyclohexadiene and acrylonitrile.30 The PET
reaction was performed by irradiation at 300 nm with
Pyrex-filtered light to get a clean nπ* excitation of the
carbonyl compound using an excess of triethylamine as
the electron donor.31,32
All three compounds undergo regioselective ring open-
ing of the so-called exo-cyclic C-C bond. The monocyclic
products 4 and 5 are formed via primary radicals of the
type V rather than the more stable tertiary radical33 of
an alternative endo-cyclic ring opening (Scheme 3). The
results are summarized in Table 1. Obviously, stereo-
electronic effects control this course of reaction because
of a favorable interaction between the SOMO (2p orbital
at C of the ketyl radical anion) and the antibonding
orbitals of the exo-cyclic cyclopropane bond.3d Unlike the
MO’s of the endo-cyclic cyclopropane, the C-C bond and
the 2p orbital in the exo-cyclic compound are orthogonal.
In addition, cleavage of this latter bond would lead to
ring-enlarged systems increasing the strain energy.34 For
only two derivatives of bicyclo[4.1.0]heptan-5-ones sub-
stituted by a methoxycarbonyl group in position 1 has
this type of thermodynamically-driven reaction been
observed.19,35 In both cases the strained ring (cyclobutane
or cyclopropane) is substituted at C-3 by a methoxycar-
bonyl group.
Analogously, the PET reductive cleavage of 3 leads to
the bicyclo[3.3.0]octan-3-one 6. However, we did not
observe the high yield of 79% reported by Pandey and
co-workers.36
Ta n d em F r a gm en ta tion -Cycliza tion of r-Cyclo-
p r op yl Keton es w ith a n Un sa tu r a ted Sid e Ch a in .
Our concept of the tandem fragmentation-cyclization is
illustrated in Scheme 4 for unsaturated bicyclo[2 + n.1.0]-
alkanones (n ) 1, 2). Irradiation of VI in the presence
of triethylamine in acetonitrile (λ > 300 nm) leads to the
ketyl radical anion VII which is subjected to a regiose-
lective cleavage of the cyclopropane. The distonic radical
anion VIII cyclizes to IX in a radical process. Finally,
the product X is formed after protonation and H-abstrac-
tion.37 Depending on the position of the unsaturated side
chain, various annealated and spirocyclic ketones are
accessible by this method. In the following, we first
describe the synthesis of the starting materials.
Syn th esis of 4-Allyl Cyclop r op yl Keton es 13 a n d
14. 3-Ethoxycyclopent-2-enone (7)38 and 3-ethoxycyclo-
(23) Baldwin, J . E.; Cutting, J .; Dupont, W.; Kruse, L.; Silberman,
L.; Thomas, R. C. J . Chem. Soc., Chem. Commun. 1976, 734, 736.
(24) (a) Beckwith, A. L. J . Tetrahedron 1981, 37, 3073. (b) Beckwith,
A. L. J . Chem. Soc. Rev. 1993, 22, 143.
(25) (a) Giese, B. Angew. Chem., Int. Ed. Engl. 1985, 24, 553. (b)
Giese, B. Radicals in Organic Synthesis. Formation of Carbon-Carbon
Bonds; Pergamon Press: Oxford, 1986; p 141.
(26) Curran, D. P. Synthesis 1988, 417, 489.
(27) Cossy, J .; Bouzide, A.; Ibhi, S.; Aclinon, P. Tetrahedron 1991,
47, 7775.
(28) Hasegawa, E.; Ishiama, K.; Horaguchi, T.; Shimizu, T. J . Org.
Chem. 1991, 56, 1631.
(29) Corey, E. J .; Chaycovsky, M. J . Am. Chem. Soc. 1965, 87, 1353.
(30) (a) Demuth, M.; Mikhail, G. Synthesis 1985, 145. (b) Demuth,
M. Photochemical Key Steps in Organic Synthesis; Mattay, J ., Gries-
beck, A. G., Eds.; Verlag Chemie: Weinheim, 1994; p 73.
(31) At shorter wavelengths (<300 nm) photoionization of the
triethylamine cannot be excluded similar to PET processes in hexa-
methylphosphoric acid triamide (HMPA)scf. ref 32 and H. H. Morrison,
Purdue University, private communication.
(34) Haufe, G.; Mann, G. Chemistry of Alicyclic Compounds; Elsevi-
er: Amsterdam, 1989; p 87.
(32) (a) Dornhagen, J .; Klausener, A.; Runsink, J .; Scharf, H.-D.
Liebigs Ann. Chem. 1985, 1838. (b) Klausener, A; Beyer, G.; Leismann,
H.; Scharf, H.-D.; Mu¨ller, E.; Runsink, J .; Go¨rner, H. Tetrahedron 1989,
45, 4989.
(33) Viehe, H. G.; J anousek, Z.; Merenyi, R. Substituent Effects in
Radical Chemistry; D. Reidel Publishing Co: Dordrecht, 1986; p 1.
(35) Cossy, J .; Furet, N. Tetrahedron Lett. 1993, 34, 8107.
(36) Pandey, B.; Rao, A. T.; Dalvi, P. V.; Kumar, P. Tetrahedron
1994, 50, 3843.
(37) In Scheme 4 one plausible mechanism is suggested. Alterna-
tively, protonation may take place before C-C bond cleavage or
cyclization.

Photoinduced Electron Transfer Reactions
J . Org. Chem., Vol. 61, No. 25, 1996 8887
Sch em e 4
F igu r e 1.
Sch em e 6
Sch em e 5
hex-2-enone (8)39 were alkylated with allyl bromide under
kinetic deprotonation conditions. Reduction of 9 and 10
by lithium aluminum hydride40 followed by the Corey-
Chaycovsky procedure29 gave 13 and 14 in good yield
(Scheme 5). On the basis of the NMR analysis (in 1:1
benzene-d6/CDCl3, H-H COSY, 1J (CH)-correlated, NOE),
the trans-isomers were shown to be the major diastereo-
isomer. An enhancement of the intensity of the C5-H
was observed after saturating the endo-cyclic C7-H and
vice versa (Figure 1).
Sch em e 7
Syn th esis of 2-Allyl Cyclop r op yl Keton es 25 a n d
26. In general, two procedures have been developed for
the synthesis of 2-alkylated cycloalkenones. The first
starts with a Birch reduction of an appropiate anisole
derivative.41,42 We have applied the second strategy
using the Stille reaction of a 2-iodocycloalkenone and allyl
bromide as the key step (Scheme 6). The R-bromocy-
cloalkenone ketals 19 and 20 were synthesized from
2-cyclopentenone 15 and 2-cylohexenone 16. The follow-
ing procedures are already reported in the literature43,44
and were slightly modified to obtain the 2-allylcycloal-
kenones 23 and 24. Applying the sulfur ylide method,
the starting materials 25 and 26 are accessible in overall
good yield. Compound 28 was obtained from the com-
mercially available cis-jasmone (27).
enones 29 and 3046 which were converted to 31 and 32
as usual (Scheme 7).
Syn th esis of 6-Allyltr icyclo[3.3.0.02,8]octa n -3-on e
(37). The oxadi-π-methane rearrangement30 is used as
the key step in the synthesis of 37. Quenching the
kinetically deprotonated compound 12 with trimethylsilyl
chloride yielded the trimethylsilyl enol ether 33 which
was subjected to a Diels-Alder reaction with maleic an-
hydride. The attack was expected to occur from the non-
hindered side in the typical endo mode. The hydrolysis
of the silyl enol ether and the anhydride was performed
in one step. The yield-determining step of the total
synthesis was the bisdecarboxylation of 35. Although the
electrochemical method had been successfully applied in
similar cases,47 we obtained 36 in only a poor yield of
Syn th esis of 3-Alk en ylbicyclo[4.1.0]h ep ta n -5-on es
31 a n d 32. Grignard reaction of 3-ethoxycyclohexenone
(8) with ω-bromoalkenes45 gave the 3-alkenyl-substituted
(38) Fuchs, R.; McGarrit, J . Synthesis 1992, 373.
(39) Gannon, W. F.; House, H. O. Org. Synth. 1960, 40, 41.
(40) Stork, G.; Danheiser, R. L. J . Org. Chem. 1973, 38, 1775.
(41) Wilds, G.; Nelson, B. J . Am. Chem. Soc. 1953, 75, 5360.
(42) Taber, D. F.; Gunn, P. B.; Chin, I. C. Org. Synth. 1983, 61, 59.
(43) Smith, A.; Branca, S.; Guaciaro, M.; Wovkilich, P.; Korn, A. Org.
Synth. 1983, 61, 65.
(44) Ladlow, M.; Pattenden, G. J . Chem. Soc., Perkin Trans. 1 1985,
1107.
(45) Kraus, G. A.; Landgrebe, K. Synthesis 1984, 885.
(46) Becker, D.; Harel, Z.; Nagler, M.; Gillon, A. J . Org. Chem. 1982,
47, 3297.
(47) Warren, C. B.; Bloomfield, J . J .; Chikos, J . S.; House, R. A. J .
Org. Chem. 1973, 38, 4011.

8888 J . Org. Chem., Vol. 61, No. 25, 1996
Kirschberg and Mattay
Ta ble 2. P ET Rea ction (Ta n d em
F r a gm en ta tion -Cycliza tion )
Sch em e 8
5%. On the other hand, the procedure using lead tetra-
acetate48 gave better results with an isolated yield of 25%.
The triplet-sensitized rearrangement of 36 yielded 37
without formation of any side products (Scheme 8).
Ta n d em F r a gm en t a t ion -Cycliza t ion R ea ct ion s
by Red u ctive P ET. The results of the tandem frag-
mentation-cyclization reaction of various R-cyclopropyl
ketones bearing an unsaturated side chain are sum-
marized in Table 2. Bicycloalkanones derived from
cyclohexenone and cyclopentenone undergo this type of
reductive rearrangement independent of the position of
the side chain (R, â, and γ). However, the mode and the
efficiency of the cyclization process depend on structural
features of the starting material. For example, 14
cyclizes to 38 following the well-established 5-exo-trig
mode. Similar behavior is seen with 28, 31, and 37,
leading to either annealated or spirocyclic and briged ring
systems. On the other hand, compound 13, which
resembles 14, rearranges to 39 in a 6-endo fashion.
Obviously, the stereochemical arrangement of the allyl
group and the cyclopropane (trans) controls the mode of
cyclization, leading to a trans-fused bicyclo[4.3.0]nonanone.
In the case of a 5-exo cyclization, an unfavorable trans-
bicyclo[3.3.0]octanone would have been formed. In gen-
eral, a cyclization to a cyclohexanone proceeds with low
efficiency (e.g., 13 f 39 and 32 f 42), leading to large
amounts of polymeric material. We also tested the scope
of the SmI2 method. However, in most cases, the
procedure gives lower yields compared to the PET
method. In the case of 37, even the SmI2 method failed
to give the rearranged product 44. Only if the photo-
chemical competition decreased the efficiency of the
fragmentation-cyclization process would this stochio-
metric reduction gives better results. Whereas the cis-
jasmone derivative (28) leads to a mixture of rearrange-
ment 43 and oxetane products, under PET conditions
only 43 is formed with SmI2. For reasons of clarity, the
proposed mechanism for the formation of 44 is shown in
Scheme 9.
a
b
Isolated yield referring to starting material consumed. Iso-
lated yield. c Reaction with Sml2. For structure of oxetanes see
Table 3 (45, 46).
d
Sch em e 9
Generally, the stereochemistry of the substituents is
preserved during the rearrangement, and in addition, in
most cases, one diastereomer is preferentially formed
during the cyclization step (e.g., 38 in a 9:1 ratio). In
case of the exo cyclizations, the relative stereochemistry
of the methyl group could not be assigned. Only a
comprehensive NMR analysis of 44 allowed its stereo-
chemical assignment. In Figure 2 the decisive NOE
experiments of 44 are shown.
In tr a m olecu la r Oxeta n e F or m a tion . The oxetanes
that were formed from 28 as well as 43 were of great
interest to us because of their complex structure. We
decided to test the reaction in the absence of any electron
donor in order to avoid the formation of the fragmenta-
tion-cyclization product 43 (Table 3). The irradiations
(48) Wolinski, J .; Login, R. B. J . Org. Chem. 1972, 37, 121.

Photoinduced Electron Transfer Reactions
J . Org. Chem., Vol. 61, No. 25, 1996 8889
Sch em e 10
F igu r e 2.
Ta ble 3. In tr a m olecu la r P a ter n o-Bu1 ch i Rea ction
the geometric flexibility is restricted by the cyclopropane
ring leading to the preferred formation of the straight
adducts in our case.
P ET Rea ction s of r-Ep oxy Keton es. In addition to
the R-cyclopropyl ketones, the corresponding R-epoxy
ketones were of interest to us. These compounds provide
access to tetrahydrofuran systems assuming an analo-
gous fragmentation-cyclization process would operate
(49 f XIV). As an easily accessible model for this
assumption, we chose the R-epoxy derivative 49 of cis-
jasmone 27.
The PET reaction of 49 in the presence of TEA yielded
jasmone after chromatography on silica. We assume a
mechanism involving a radical anion XVI as the key
intermediate (Scheme 10). The lack of cyclization in the
course of the reaction is ascribed to the high negative
charge density on the foremost epoxy group rather than
the enolate. Earlier reports of Hasegawa28 and Cossy29
support our hypothesis. Furthermore, the alternative
reduction using SmI2 yielded the same product even upon
substitution of the DMPU by HMPA or running the
reaction at a lower temperature of -78 °C. The electron
transfer mechanism is also supported by the already
observed photoreaction of R-epoxy ketones with allyl-
tributyltin leading to products which result from a C-O
rather than a C-C bond cleavage.50
N-Silyla m in es a s Electr on Don or s. So far triethyl-
amine was used as the reducing agent providing not only
the electron but most probably the proton and eventually
even the hydrogen during the fragmentation-cyclization
sequence (cf. Scheme 3 and 4). Another leaving group
which may act as electrofuge is the trimethylsilyl group.
Whereas R-silylated amines have been used already by
Mariano and co-workers,12,51,52 the behavior of N-silylated
amines is unknown so far. Therefore, we used these
compounds as electron donors, hoping that the silyl group
might be transferred to the oxygen of the former ketone.
The first results obtained in the reaction of 2 with
a 5-fold excess of N,N-dimethyl(trimethylsilyl)amine
(Me2NTMS) were quite encouraging. The silyl enol ether
were performed in benzene solution using Pyrex-filtered
light of a wavelength >300 nm. Two diastereomeric
oxetanes 45 and 46 (3.2:1) were formed in nearly quan-
titative yield (confirmed by a NMR spectra of the crude
mixture). The smaller isolated yield was caused by
decomposition of the products during the workup proce-
dure. The assignment of 45 and 46 as straight adducts
(head-to-head) was confirmed on the basis of the NMR
experiments. The vicinal relationship of the 3-H and 4-H
protons as well as the methylene protons of the ethyl
substituent was confirmed using homonuclear decoupling
techniques. In the case of 45, the vicinal coupling of 2.1
Hz between 3-H and 4-H is consistent with a dihedral
angle of 90° between these protons. For 46, however, the
coupling constant of 6.7 Hz between 3-H and 4-H
indicates a dihedral angle of roughly 0°.
We also synthesized the unsubstituted 2-oxatetracyclo-
[4.4.0.01,4.06,8]decane. Irradiation of 25 in benzene in the
absence of any electron donor led to the formation of the
two isomeric compounds 47 and 48 (8:1) in nearly
quantitative yield (Table 3). Again, the decreased iso-
lated yield was due to the instability of the material upon
workup. Compound 47 was assigned as straight oxetane
because of its similarity to 45 and 46. In addition, the
vicinal coupling constants of 6.2 and 2.1 Hz of 4-H
support this structure. The minor adduct 48 was isolated
only in a very small amount because it is even less stable
than 47. The assignment as a crossed oxetane was
mainly based on the chemical shifts in the 13C NMR
spectra (e.g., low-field shifted signal of tertiary carbon
1
at δ ) 88.5 ppm). Additional low-field H resonances at
5.31, 4.97, and 4.77 ppm indicate a close proximity to
oxygen and, therefore, support the crossed structure.
Our findings resemble a report of Kossanyi et al.
concerning photoreactions of 2-allylcyclopentanone.49 The
authors observed the formation of both crossed and
straight oxetanes in nearly equal amounts. Obviously,
(50) Hasegawa, E.; Ishiyama, K.; Horaguchi, T.; Shimizu, T. Tet-
rahedron Lett. 1991, 32, 2029.
(51) Xu, W.; Zhang, X.-M.; Mariano, P. S. J . Am. Chem. Soc. 1991,
113, 8863.
(52) Pandey, G.; Reddy, G. D.; Kumaraswamy, G. Tetrahedron 1994,
50, 8185.
(49) (a) Kossanyi, J .; J ost, P.; Furth, B.; Daccord, G.; Chaquin, P.
J . Chem. Res., Synop. 1980, 368. (b) Furth, B.; Daccord, G.; Kossanyi,
J . Tetrahedron Lett. 1975, 48, 4259.

8890 J . Org. Chem., Vol. 61, No. 25, 1996
Kirschberg and Mattay
Sch em e 13
Sch em e 11
Sch em e 12
in acetonitrile containing 24 equiv of methanol yielded
several products, of which not one was identified as the
methyl ester analogue of the amides 52 and 53.
Similarily, we investigated the reaction of epoxyjas-
mone (49) with Me2NTMS (5-fold excess). After chro-
matographic purification, 55 was isolated in 44% yield.
The same experiment, however, in the presence of
methanol or methanol-d4 provided the esters 54 and the
oxetane 56. These results support the formation of a
ketene intermediate (XX in Scheme 13). Therefore, we
assume the following mechanism: In a first photochemi-
cal event, the epoxy ketone 49 rearranges by ring
contraction via XIX and loss of ethylene to the ketene
XX, similar to the findings of Marcos, Reusch, and
Gibson.53,54 The reaction of ketenes with N-silylated
amines is known. For example, ketene itself yields N,N-
dimethyl-2-(trimethylsilyl)acetamide upon reaction with
Me2NTMS55 and even diketene shows similar reactions.56
Therefore, we assume an addition of Me2NTMS to XX
under formation of XXI which decomposes under our
workup procedures to 55. The scavenging experiments
with CH3OH and CD3OD support our proposed mecha-
nism. In summary, with R-epoxy ketones of the type 49
and N-silylated amines, the photoinduced rearrangement
efficiently competes with a PET process.
50 was formed in 34% yield along with 51 in smaller
amounts (Scheme 11). On the other hand, 51 became
the major product after PET reaction in the presence of
only 1 equiv of Me2NTMS. The thermal formation of
either product could be excluded on the basis of control
experiments.
We assume a similar mechanism as that shown in
Scheme 3 for the corresponding reaction with triethyl-
amine. The key steps are PET and the transfer of the
TMS cation to the ketyl radical anion or the enolate,
respectively. This reaction may proceed “SN2-like“ due
to the high concentration of the silylated amine. The
mechanism of the formation of the ether 51 is still
unclear. Since it is preferentially observed at lower
concentrations of the amine which favors dissociation of
the primarily generated radical ion pair, it might be
formed from the ring-opened cyclohexanone 5 in a
secondary process after reduction to the alcohol. The
photoreduction of ketones to secondary alcohols in aceto-
nitrile containing triethylamine had already been de-
scribed by us in an earlier paper.19c Later, Cossy and
Furet confirmed this observation.35 Similarily, 5 could
be reduced to either its alcohol followed by silylation in
the presence of Me2NTMS or its radical cation.
The PET reactions of 3 with one equivalent of silylated
amines took unexpected courses. The only products
which could be isolated in up to 35% yield were the ring-
opened amides 52 and 53. The cis relationship of the
two substituents was verified on the basis of the coupling
constant of 7.1 Hz between 1-H and 2-H which is typical
for dihedral angles of roughly 0°. In Scheme 12, a
plausible mechanism is shown which is further supported
by the following control experiments: Irradiation of 6 in
acetonitrile and in the presence of diethylamine produced
53 as the only product. However, there is no direct path
from 3 to the ring-opened products since photolysis of 3
Con clu sion
R-Cyclopropyl ketones cleave homolytically one C-C
bond of the three-membered ring during the course of
the PET reaction with triethylamine. In the presence of
a well-chosen unsaturated side chain, a cyclization is
feasable to yield ring-annealated or spirocyclic products.
This reaction represents an example of the extensively
studied tandem (domino, cascade) reactions.57 The reac-
tion of the R-epoxy ketone 49 with triethylamine is
assumed to proceed via an R-acyl radical as the most
(53) Marcos, C. S.; Reusch, W. J . Am. Chem. Soc. 1967, 89, 3363.
(54) Gibson, T. J . Org. Chem. 1974, 39, 845.
(55) Sheludyakov, V. D.; Kozyukov, V. P.; Pretrovskaya, L. I.;
Mironov, V. F. Khim. Geterotsikl. Soedin. 1967, 1, 185; Chem. Abstr.
1967, 67, 43858.
(56) Bankov, Y. I.; Burlachenko, G. S.; Kostyuk, A. S.; Lutsenki, I.
F. Zh. Obshch. Khim. 1966, 36, 1859; Chem. Abstr. 1967, 66, 65576z.

Photoinduced Electron Transfer Reactions
J . Org. Chem., Vol. 61, No. 25, 1996 8891
mmol of the ketone, 1 mmol or 5 mmol of the N-silylated
amines, and 12 mL of dry acetonitrile. During irradiation, the
reaction was monitored by GLC. After complete disappearance
of the starting material, the solvent was removed under
reduced pressure and the products were isolated by column
chromatography using either silica or Al2O3 (neutral).
Gen er a l P r oced u r e E (Sm I2 Red u ction Accor d in g to
Moth er w ell). A 1 mM solution of SmI2 in THF was added to
a THF solution (13 mL) of 1.0 mmol of the ketone and 3 mL of
DMPU under argon atmosphere until the color turned violet.
The reaction was quenched by addition of a saturated, aqueous
solution of NaHCO3. Extraction with ether, washing with
water and brine, and drying over MgSO4 gives the product
solution.
Gen er a l P r oced u r e F (Sm I2 Red u ction ). The same
reaction conditions as in procedure E were applied. The only
variation was introduced upon work up. The blue solution
which was obtained after the addition of the SmI2 solution was
quenched by adding only 1 mL of saturated NaHCO3 solution
which caused the separation of a clear solution and solid
samarium hydroxide. The THF was removed under reduced
pressure, and 50 mL of ether and 20 mL of water were added.
The aqueous solution was further extracted with ether, and
the combined organic layers were washed with brine and dried
over magnesium sulfate. The products were isolated using
either HPLC or column chromatography on silica.
reasonable intermediate. The preliminary results ob-
tained in the photochemical reaction of R-cyclopropyl
ketones as well as R-epoxy ketones with the N-silylated
amines showed a complex behavior depending mainly on
the nature of the carbonyl compound. The expected
formation of silyl enol ethers is not an exclusive reaction
pathway. In addition, an acetamide function was acces-
sible during the photochemical excitation of a carbonyl
group in the presence of the N-silylated amines via either
a direct addition of the amine to a ketene or the addition
of the dialkylamine derived in the course of the reaction
from a loss of the silyl group. Furthermore, the intramo-
lecular oxetane formation from 25 and 28 has been
studied, which showed a remarkable regioselectivity. This
behavior was explained by the presence of the cyclopropyl
moiety imposing some steric demands on the starting
material.
Exp er im en ta l Section
Sta n d a r d P r oced u r es. All solvents were dried according
to standard procedures. Benzene (pro analysis), chloroform
(pro analysis), and pyridine (dry) were used as purchased.
Samarium diiodide solution was puchased from Fluka. The
irradiations were performed in a Rayonet photoreactor (South-
ern New England) fitted with 300 nm lamps using Pyrex or
quarz tubes of ca. 12 mL volume. Abbreviations used are the
following: pe, petrol ether; e, ether; ch, cyclohexane; ee, ethyl
acetate.
Gen er a l P r oced u r e A (Cyclop r op a n iza tion of En on es).
A portion (1.1 molar equiv) of sodium hydride dispersion in
mineral oil (55-65%) was washed three times with petroleum
ether. Traces of the solvent were removed under reduced
pressure. An argon atmosphere was introduced, and 1.1 molar
equiv of trimethylsulfoxonium iodide was added followed by
dry DMSO (2 mL/1 mmol of enone). The solution was stirred
for 30 min, until the evolution of hydrogen ceased. The enone
was added, dissolved in dry DMSO (1 mL/10 mmol of enone),
and the solution was stirred at room temperature for 4 h. The
mixture was poured onto ice water and extracted with ether
(four times). The combined organic layers were washed with
water and brine and dried over magnesium sulfate. The
products were isolated using column chromatography on silica.
Syn th esis of th e Sta r tin g Ma ter ia ls: 1-Meth ylbicyclo-
[3.1.0]h exa n -4-on e (1). The cyclopropanization reaction
(procedure A) of 4.22 g (43.0 mmol) of 3-methylcyclopentenone
yielded 1.85 g (39%) of 1 after chromatography on Al2O3
(eluent: pe/e 8:2): IR (neat) 2920 (s) cm-1, 2860, 1715 (s, CdO),
1285, 1175, 1020, 895, 770; 1H NMR (300 MHz, CDCl3) δ 1.12
(m, 2 H), 1.35 (s, 3 H, CH3), 1.60 (dd, J ) 4.5, 5.0 Hz, 1 H),
1.86-2.20 (m, 4 H); 13C NMR (75 MHz, CDCl3) δ 21.1 (CH2),
21.4 (CH3), 29.2 (CH2), 30.2 (Cq), 32.8 (CH2), 35.2 (CH), 215.0
(Cq); MS (70 eV) m/ z ) 111 (M+ + 1, 12), 110 (M+, 30), 82
(58), 67 (100), 39 (81); UV (acetonitrile) λmax) 208 nm (ꢀ max
)
4080), λ ) 268 nm (ꢀ ) 185). Anal. Calcd for C7H10O: C,
76.32; H, 9.15. Found: C, 75.87; H, 9.29.
1-Meth ylbicyclo[4.1.0]h ep ta n -5-on e (2). The cyclopro-
panization reaction (procedure A) of 5.5 g (50.0 mmol) of
3-methylcyclohexenone yielded 2.91 g (47%) of 2 after chro-
matography on silica (eluent: ch/ee 95:5): IR (neat) 2940 (s)
cm-1, 2870, 1685 (s, CdO), 1445, 1390, 1320, 1305, 1245, 1090,
945, 865; 1H NMR (300 MHz, CDCl3) δ 0.91 (dd, J ) 10.3, 5.1
Hz, 1 H, 7a-H), 1.22 (s, 3 H, CH3), 1.40 (dd, J ) 4.5, 4.5 Hz, 1
H, 7b-H), 1.55-1.80 (m, 4 H), 1.90-2.10 (m, 2 H), 2.28 (m, 1
H); 13C NMR (75 MHz, CDCl3) δ 17.7 (CH2, C-7), 18.3 (CH2),
24.2 (Cq, C-1), 25.0 (CH3), 28.3 (CH2), 34.6 (CH, C-6), 36.1
(CH2, C-4), 209.2 (Cq, C-5); MS (70 eV) m/ z 124 (M+, 38), 81
Gen er a l P r oced u r e B (Ep oxyd a tion of En on es).
A
solution of 7.0 mmol of the enone in 10 mL of methanol was
cooled to 0 °C, and 4.8 mL of 30% hydrogen peroxide was
added. This solution was treated with a mixture of 0.8 mL of
6 M NaOH and 8.0 mL of methanol. After the mixture was
stirred for 3 h at room temperature, the solution was poured
onto ice water and extracted three times with ethyl acetate.
The combined organic layers were washed with saturated
NaHCO3 solution and brine and were dried over Na2SO4. The
epoxide was isolated after column chromatography using silica.
Gen er a l P r oced u r e C (P ET Rea ction w ith Tr ieth yl-
a m in e). The solutions of the cyclopropyl ketones, triethyl-
amine (4-5 equiv), and decane (internal standard) in dry
acetonitrile were placed in several tubes, degassed, and
irradiated. The reaction course was monitored by TLC and
GLC. In a typical reaction, the best results were obtained after
roughly 5 days of irradiation time. After removal of the solvent
under reduced pressure, the products were isolated by HPLC
or column chromatography.
(80), 68 (100), 67 (100), 55 (58), 39 (50); UV (acetonitrile) λmax
)
205 nm (ꢀ ) 5310), λ ) 282 nm (ꢀ ) 37). Anal. Calcd for
max
C8H12O: C, 77.37; H, 9.74. Found: C, 77.01; H, 9.75.
4-(P r op -2′-en yl)bicyclo[4.1.0]h ep ta n e (14). The cyclo-
propanization reaction (procedure A) of 1.78 g (13.0 mmol) of
4-(prop-2′-enyl)cyclohexenone (12) yielded 860 mg (44%) of 14
after chromatography on silica (eluent: ch/ee 93:7). The
product was obtained as a 6:1 mixture (GLC) of two diaste-
reoisomers. The spectroscopic data refer to the main isomer:
IR (neat) 3060 cm-1, 2900, 1680 (s, CdO); 1H NMR (300 MHz,
CDCl3) δ 1.18 (ddd, J ) 9.7, 8.2, 5.3 Hz, 1 H, 7-H exo), 1.25
(ddd, J ) 5.9, 5.3, 4.6 Hz, 1 H, 7-H endo), 1.58-1.82 (m, 4 H,
6-H, 4-H, 1-H), 2.08-2.36 (m, 5 H, 1′-H, 5-H, 3-H), 5.03-5.12
(m, 2 H, 3′-H), 5.81 (m, 1 H, 2′-H); 1H NMR (360 MHz, CDCl3/
C6D6 1:1) δ 0.75 (ddd, J ) 9.7, 8.2, 5.3 Hz, 1 H, 7-H exo), 0.81
(ddd, J ) 5.9, 5.3, 4.6 Hz, 1 H, 7-H endo), 1.17 (m, 2 H, 4a-H,
6-H), 1.41 (m, 1 H, 4b-H), 1.50 (ddd, J ) 9.7, 7.6, 4.7 Hz, 1 H,
1-H), 1.70 (m, 1 H, 5-H), 1.80-2.00 (m, 4 H, 3-H, 1′-H), 4.86-
4.94 (m, 2 H, 3-H), 5.60 (m, 1 H, 2′-H); 13C NMR (75 MHz,
CDCl3) δ 12.5 (CH2, C-7), 23.4 (CH2), 23.8 (CH), 25.4 (CH),
31.3 (CH), 32.8 (CH2), 38.9 (CH2), 116.6 (CH2, C′-3), 136.4 (CH,
C′-2), 209.5 (Cq); 13C NMR (90 MHz, CDCl3/C6D6 1:1) δ 13.3
(CH2, C-7), 24.6 (CH), 24.7 (CH2, C-4), 26.4 (CH), 32.6 (CH,
C-5), 33.9 (CH2), 40.0 (CH2), 117.5 (CH2, C-3′), 137.5 (CH, C-2′),
209.3 (Cq); MS (70 eV) m/ z 151 (M+ + 1, 14), 150 (M+, 10),
109 (35), 93 (30), 91 (38), 79 (82), 77 (32), 67 (62), 55 (26), 41
Gen er a l P r oced u r e D (P h otoch em ica l Tr a n sfor m a tion
in th e P r esen ce of N-Silyla ted Am in es). Dried and cooled
quartz reaction tubes (15 mL of volume) were filled with 1
(57) The J anuary issue of Chem. Rev. (Wender, P. A., Guest Editor)
contains several examples of tandem, domino, and cascade reactions
(general theme: Frontiers in Organic Synthesis): (a) Tietze, L. F.
Chem. Rev. 1996, 96, 115. (b) Denmark, S. E.; Thorarensen, A. Chem.
Rev. 1996, 96, 137. (c) Winkler, J . D. Chem. Rev. 1996, 96, 167. (d)
Ryu, I.; Sonoda, N.; Curran, D. P. Chem. Rev. 1996, 96, 177. (e)
Parsons, P. J .; Penkott, C. S.; Skell, A. J . Chem. Rev. 1996, 96, 195. (f)
Wang, K. K. Chem. Rev. 1996, 96, 207.

8892 J . Org. Chem., Vol. 61, No. 25, 1996
Kirschberg and Mattay
(49), 39 (100). Anal. Calcd for C10H14O: C, 79.95; H, 9.39.
Found: C, 79.84; H, 9.92.
7.0 Hz, 1 H, 4′-H); 13C NMR (75 MHz, CDCl3) δ 17.4 (CH2),
18.6 (CH2), 23.6 (Cq), 25.8 (CH2), 33.4 (CH2), 33.8 (CH), 36.8
(CH2), 37.5 (CH2), 38.6 (CH2), 114.9 (CH2, C-5′), 138.6 (CH,
C-4′), 209.4 (Cq); MS (70 eV) m/ z 178 (M+, 5), 135 (30), 110
(72), 107 (32), 95 (52), 94 (42), 93 (69), 81 (76), 79 (90), 68 (81),
67 (100), 55 (76), 39 (37). Anal. Calcd for C12H18O: C, 80.85;
H, 10.18. Found: C, 80.61; H, 10.38.
4-(P r op -2′-en yl)bicyclo[3.1.0]h exa n -2-on e (13). The cy-
clopropanization reaction (procedure A) of 250 mg (2.04 mmol)
of 4-(prop-2′-enyl)cyclopentenone (11) yielded 140 mg (50%)
of 13 after chromatography on silica (eluent: pe/e 8:2). The
observed selectivity was 9:1 favoring the trans-isomer: IR
(neat) 3070 cm-1, 2900, 1720 (s, CdO); 1H NMR (300 MHz,
CDCl3) δ 0.98 (ddd, J ) 4.7, 4.5, 3.1 Hz, 1 H, 6-H), 1.20 (dddd,
J ) 8.9, 7.4, 4.8, 1.4 Hz, 1 H, 6-H), 1.72-1.83 (m, 2 H), 1.97
(ddd, J ) 7.9, 4.8, 4.8 Hz, 1 H, 1-H), 2.06-2.30 (m, 3 H), 2.37
(m, 1 H), 5.03-5.13 (m, 2 H, 3′-H), 5.78 (ddt, J ) 17.4, 9.5, 6.9
Hz, 1 H, 2′-H); 1H NMR (360 MHz, C6D6) δ 0.39 (ddd, J ) 4.6,
4.6, 3.2 Hz, 1 H, 6-H), 0.55 (dddd, J ) 8.9, 7.5, 4.8, 1.3 Hz, 1
H, 6-H), 1.35 (ddd, J ) 7.7, 4.7, 4.7 Hz, 1 H, 1-H), 1.46 (dddd,
J ) 8.7, 4.6, 3.1, 1.1 Hz, 1 H, 5-H), 1.53 (m, 1 H, 3a-H), 1.70-
1.90 (m, 4 H, 3b-H, 4-H, 1′-H), 4.82-4.95 (m, 2 H, 3′-H), 5.50
(m, 1 H, 2′-H); 13C NMR (75 MHz, CDCl3) δ 13.8 (CH2, C-6),
27.0 (CH, 2×), 34.9 (CH), 37.8 (CH2), 40.6 (CH2), 117.3 (CH2,
C-3′), 135.4 (CH, C-2′), 214.1 (Cq, C-2); 13C NMR (90 MHz,
C6D6) δ 13.2 (CH2, C-6), 26.6 (CH, C-1), 27.1 (CH, C-5), 35.2
(CH, C-4), 38.1 (CH2, C-3), 41.0 (CH2, C-7), 117.3 (CH2, C-3′),
5-Meth yl-1-(pen t-2′-en yl)bicyclo[3.1.0]h exan -2-on e (28).
The cyclopropanization reaction (procedure A) of 3.30 g (20.0
mmol) of cis-jasmone (27) yielded 1.93 g (54%) of 28 after
chromatography on silica (eluent: ch/ee 93:7): IR (neat) 3050
1
cm-1, 2960, 2860, 1715 (s, CdO); H NMR (300 MHz, CDCl3)
δ 0.84 (d, J ) 5.0 Hz, 1 H, 6a-H), 0.97 (t, J ) 7.5 Hz, 3 H,
5′-H), 1.09 (d, J ) 5.0 Hz, 1 H, 6b-H), 1.32 (s, 3 H, 12-H), 1.76-
1.90 (m, 1 H), 1.95-2.23 (m, 6 H), 2.47 (dd, J ) 16.0, 6.7 Hz,
1 H), 5.25-5.45 (m, 2 H, 2′-H, 3′-H); 13C NMR (75 MHz, CDCl3)
δ 14.0 (CH3), 18.8 (CH3), 20.3 (CH2), 23.5 (CH2), 24.5 (CH2),
25.6 (CH2), 28.8 (CH2), 32.4 (Cq), 41.3 (Cq), 126.1 (CH), 132.2
(CH), 214.9 (Cq); MS (70 eV) m/ z 179 (M+ + 1, 10), 178 (M+,
48), 149 (100), 121 (25), 107 (22), 93 (26), 79 (22), 55 (20).
Bicyclo[2.2.2]oct-5-en -2-on e (P r ecu r sor of 3). A solution
of 4.5 g (26 mmol) of 5-chloro-5-cyanobicyclo[2.2.2]oct-2-ene in
30 mL of DMSO was heated with a mixture of 3.5 g of KOH
in 2.5 mL of water at 60 °C. After 6 h, the reaction mixture
was poured into 50 mL of ice water and extracted four times
with 50 mL portions of pentane. The combined organic layers
were dried over Na2SO4. Two and a half grams (79%) of the
ketone was obtained after chromatography on silica (eluent:
ch/ee 9:1): IR (KBr) 3040 cm-1, 2950, 2860, 1700 (s, CdO); 1H
NMR (300 MHz, CDCl3) δ 1.10-2.05 (m, 6 H), 2.92 (m, 1 H),
3.07 (m, 1 H), 6.13 (ddd, J ) 7.8, 6.4, 1.4 Hz, 1 H), 6.41 (ddd,
J ) 8.1, 6.7, 1.2 Hz, 1 H); 13C NMR (75 MHz, CDCl3) δ 22.8
(CH2), 24.6 (CH2), 32.2 (CH), 40.3 (CH2), 48.4 (CH), 128.3 (CH),
136.9 (CH), 212.8 (Cq); MS (70 eV) m/ z 123 (M+ + 1, 5), 122
(M+, 4), 80 (74), 79 (100), 77 (22), 39 (35). Anal. Calcd for
C8H10O: C, 78.65; H, 8.25. Found: C, 78.59; H, 7.89.
136.2 (CH, C-2′), 211.4 (Cq, C-2); MS (70 eV) m/ z 137 (M+
+
1, 8), 136 (M+, 5), 108 (10), 95 (34), 79 (24), 67 (100), 65 (22),
55 (23), 41 (48), 39 (98).
1-(P r op -2′-en yl)bicyclo[4.1.0]h ep ta n -2-on e (26). The cy-
clopropanization reaction (procedure A) of 500 mg (4.0 mmol)
of 2-(prop-2′-enyl)cyclohexenone (24) yielded 310 g (52%) of 26
after chromatography on silica (eluent: ch/ee 9:1): IR (neat)
3080 cm-1, 2920, 2850, 1670 (s, CdO); 1H NMR (300 MHz,
CDCl3) δ 0.91 (dd, J ) 8.5, 5.5 Hz, 1 H, 7-H exo), 1.29 (dd, J
) 5.5, 5.5 Hz, 1 H, 7-H endo), 1.54-1.73 (m, 3 H), 1.87-2.11
(m, 4 H), 2.30 (ddd, J ) 17.0, 5.0, 5.0 Hz, 1 H), 2.70 (ddt, 15.0,
7.0, 1.2 Hz, 1 H), 4.92-5.03 (m, 2 H, 3′-H), 5.78 (m, 1 H, 2′-
H); 13C NMR (75 MHz, CDCl3) δ 16.6 (CH2, C-7), 19.4 (CH2),
22.3 (CH2), 24.2 (CH), 33.8 (Cq), 37.4 (CH2), 37.8 (CH2), 116.4
(CH2, C-3′), 135.9 (CH, C-2′), 209.4 (Cq); MS (70 eV) m/ z 151
(M+ + 1, 6), 150 (M+, 14), 91 (41), 79 (100), 77 (38), 43 (32), 39
(92). Anal. Calcd for C10H14O: C, 79.95; H, 9.39. Found: C,
79.88; H, 9.75.
Tr icyclo[3.3.0.02,8]octa n -3-on e (3). A solution of 1.0 g
(40.5 mmol) of bicyclo[2.2.2]oct-5-en-2-one in 60 mL of acetone
was degassed with argon and distributed among five quartz
irradiation tubes. After 24 h of irradiation at 300 nm, the
reaction was stopped, the solvent was removed under reduced
pressure, and the product was obtained after chromatography
1-(P r op -2′-en yl)bicyclo[3.1.0]h exa n -2-on e (25). The cy-
clopropanization reaction (procedure A) of 440 mg (3.6 mmol)
of 2-(prop-2′-enyl)cyclopentenone (23) yielded 360 mg (73%)
of 25 after chromatography on silica (eluent: pe/e 8:2): IR
(neat) 3060 cm-1, 2930, 2870, 1715 (s, CdO); 1H NMR (300
MHz, CDCl3) δ 0.80 (m, 1 H, 6a-H), 0.91 (dd, J ) 4.8, 4.8 Hz,
1 H, 6b-H), 1.84-2.11 (m, 5 H), 2.19 (ddt, J ) 15.3, 6.9, 1.2
Hz, 1 H, 1′a-H), 2.45 (dd, 15.0, 6.7 Hz, 1 H, 1′b-H), 4.88-4.97
on silica (eluent: ch/ee 85:5) in 68% yield: IR (neat) 3030 cm-1
,
2930, 2860, 1710 (s, CdO); 1H NMR (360 MHz, CDCl3) δ 1.42-
1.56 (m, 2 H), 1.61 (d, J ) 18.0 Hz, 1 H, 4a-H), 1.83 (dd, J )
9.1, 5.0 Hz, 1 H, 2-H), 1.87-2.06 (m, 3 H), 2.42 (dd, J ) 18.1,
9.9 Hz, 1 H, 4b-H), 2.63 (ddd, J ) 5.6, 5.5, 5.1 Hz, 1 H, 1-H),
2.85 (m, 1 H, 5-H); 13C NMR (75 MHz, CDCl3) δ 24.6 (CH2),
30.8 (CH), 36.3 (CH), 37.4 (CH), 38.9 (CH), 40.8 (CH2), 46.9
(CH2), 216.1 (Cq); MS (70 eV) m/ z 123 (M+ + 1, 45), 122 (M+,
(m, 2 H, 3′-H), 5.67 (ddt, J ) 17.6, 9.5, 6.9 Hz, 1 H, 2′-H); 13
C
NMR (75 MHz, CDCl3) δ 18.2 (CH2, C-6), 21.6 (CH2), 26.6 (CH),
31.0 (CH2), 32.4 (CH2), 36.4 (Cq), 116.4 (CH2, C-3′), 134.8 (CH,
C-2′), 214.9 (Cq); MS (70 eV) m/ z 137 (M+ + 1, 5), 136 (M+,
14), 79 (100), 77 (35), 67 (38), 41 (42), 39 (92).
6), 80 (100), 79 (38), 53 (23), 39 (66); UV (acetonitrile) λmax
208 nm (ꢀ max) 18 800), shoulder up to 310 nm.
)
5,6-Dica r b oxy-8-(p r op -2′e n yl)b icyclo[2.2.2]oct a n -2-
on e (35). An LDA solution of 8.20 g of diisopropylamine, 100
mL of dry THF, and 36 mL of 1.6 M n-BuLi was prepared. At
-78 °C, a solution of 6.70 g (49.2 mmol) of 12 in 15 mL of dry
THF was added using the septum syringe technique. After
the solution was stirred for 1 h at -78 °C, TMSCl was added
dropwise. The solution was warmed to room temperature and
stirred for an additional hour, and the solvent was removed
at reduced pressure. Pentane was added to the crude reaction
mixture, and the insoluble lithium salts were filtered off.
Again, the solvent was evaporated under reduced pressure.
The NMR spectrum of this crude reaction mixture showed a
clean formation of the desired silyl enol ether 33. The crude
reaction product was used without further purification and was
stirred with 6.02 g (60.8 mmol) of powdered maleic anhydride
for 4 h without any solvent. Hydrolysis of the silyl enol ether
and the anhydride was performed in one step. The material
was treated with 40 mL of water and 2 mL of 2 M HCl for 30
min, and then solid sodium carbonate was added until a pH
of 9-10 was reached. This solution was refluxed for 5 h, cooled
to room temperature, and acidified with 2 M HCl. The solution
was extracted with ether. The combined organic layers were
dried over MgSO4. After removal of the magnesium sulfate,
the ether was evaporated under reduced pressure. Chloroform
1-(Bu t-3′-en yl)bicyclo[4.1.0]h ep ta n -5-on e (31). The cy-
clopropanization reaction (procedure A) of 3.80 g (25.0 mmol)
of 3-(but-3′-enyl)cyclohexenone (29) yielded 1.89 g (46%) of 31
after chromatography on silica (eluent: ch/ee 9:1): IR (neat)
3060 cm-1, 2905, 2815, 1675 (s, CdO); 1H NMR (300 MHz,
CDCl3) δ 0.94 (dd, J ) 10.5, 5.4 Hz, 1 H, 7-H exo), 1.39 (dd, J
) 5.4, 5.5 Hz, 1 H, 7-H endo), 1.42-1.83 (m, 3 H), 1.93-2.09
(m, 3 H), 2.12-2.38 (m, 5 H), 4.95 (m, 1 H, 4′-H), 5.01 (ddt, J
) 18.0, 2.0, 2.0, 1 H, 4′-H trans), 5.79 (ddt, J ) 17.5, 10.5, 7.0
Hz, 1 H, 3′-H); 13C NMR (75 MHz, CDCl3) δ 17.3 (CH2), 18.5
(CH2), 25.7 (CH2), 28.1 (Cq, C-1), 30.8 (CH2), 33.7 (CH), 36.3
(CH2), 38.5 (CH2), 114.9 (CH2, C-4′), 138.3 (CH, C-3′), 209.1
(Cq); MS (70 eV) m/ z 164 (M+, 10), 110 (100), 95 (78), 93 (58),
91 (40), 79 (84), 55 (80), 39 (34).
1-(P en t-4′-en yl)bicyclo[4.1.0]h ep ta n -5-on e (32). The cy-
clopropanization reaction (procedure A) of 4.10 g (25.0 mmol)
of 3-(pent-4′enyl)cyclohexenone (30) yielded 3.10 g (70%) of 32
after chromatography on silica (eluent: ch/ee 9:1): IR (neat)
3060 cm-1, 2910, 2840, 1675 (s, CdO); 1H NMR (300 MHz,
CDCl3) δ 0.92 (dd, J ) 10.5, 5.4 Hz, 1 H, 7-H exo), 1.38 (dd, J
) 5.4, 5.5 Hz, 1 H, 7-H endo), 1.45-1.83 (m, 7 H), 1.91-2.12
(m, 4 H), 2.19-2.38 (m, 2 H), 4.95 (m, 1 H, 5′-H), 5.00 (ddt, J
) 18.0, 2.0, 2.0 Hz, 1 H, 5′-H trans), 5.79 (ddt, J ) 18.0, 10.5,

Photoinduced Electron Transfer Reactions
J . Org. Chem., Vol. 61, No. 25, 1996 8893
was added until the solid dissolved. 35 (7.1 g, 57%) was
obtained at 0 °C as a solid material: IR (KBr) 3200-2800 cm-1
δ 0.98 (t, J ) 7.6 Hz, 3 H, 5′-H), 1.50 (s, 3 H, 12-H), 1.95-2.48
(m, 7 H), 2.65 (dd, J ) 14.5, 5.5 Hz, 1 H), 5.28 (m, 1 H), 5.45
(m, 1 H); 13C NMR (75 MHz, CDCl3) δ 13.9 (CH3), 16.5 (CH3),
20.7 (CH2), 21.8 (CH2), 27.6 (CH2), 31.9 (CH2), 67.0 (Cq), 69.4
(Cq), 121.8 (CH), 135.1 (CH), 211.3 (Cq); MS (70 eV) m/ z 181
(M+ + 1, 4), 180 (M+, 10), 109 (23), 99 (100), 81 (45), 71 (27),
69 (48), 55 (23), 43 (51), 41 (58), 39 (69); UV (acetonitrile) λmax
) 206 nm (ꢀ max) 11 250), λ ) 294 nm (ꢀ ) 59). Anal. Calcd
for C11H16O2: C, 73.30; H, 8.95. Found: C, 72.97; H, 8.79.
P h otop r od u cts. 3,3-Dim eth ylcyclop en ta n on e (4). The
photolysis of 300 mg (2.72 mmol) of 1 and 2.72 g (27.2 mmol)
of TEA in 13 mL of dry acetonitrile was performed according
to procedure C. Due to the high volatility of the product 4, a
modified workup was used. The acetonitrile was not directly
removed under reduced pressure, but ether was added and
the solution was washed several times with water. The ether
was cautiously evaporated from the organic layer, and the
crude solution (3-4 mL) was subjected to chromatography on
silica (eluent: pe/e 7:3). One hundred and twenty milligrams
(39%) of 4 was isolated by this procedure: IR (neat) 2940 (s)
cm-1, 2860, 1735 (s, CdO), 1455, 1440, 1365, 1135, 875; 1H
NMR (300 MHz, CDCl3) δ 1.12 (s, 6 H, CH3), 1.78 (t, J ) 7.8
Hz, 2 H, 4-H), 2.05 (s, 2 H, 2-H), 2.31 (t, 2 H, 5-H); 13C NMR
(75 MHz, CDCl3) δ 28.8 (CH3, C-6), 36.4 (Cq, C-3), 37.2 (CH2),
37.6 (CH2), 53.6 (CH2, C-5), 212.2 (Cq, C-1); MS (70 eV) m/ z
1
(s), 1680 (s, CdO); H NMR (300 MHz, CDCl3) δ 1.42 (ddd, J
) 14.1, 4.5, 2.8 Hz, 1 H), 1.84 (m, 1 H), 1.98-2.11 (m, 3 H),
2.28-2.47 (m, 2 H), 2.55-2.71 (m, 2 H), 3.06 (brd, J ) 11.2
Hz, 1 H), 3.28 (dd, J ) 11.2, 2.6 Hz, 1 H), 5.02 (m, 2 H, 3′-H),
5.66 (ddt, J ) 17.6, 9.8, 6.7 Hz, 1 H, 2′-H); 13C NMR (75 MHz,
CDCl3) δ 29.8 (CH2), 33.8 (CH), 35.3 (CH), 36.3 (CH2), 39.3
(CH2), 44.9 (CH), 45.4 (CH), 45.8 (CH), 117.2 (CH2, C-3′), 135.3
(CH, C-2′), 178.1, 179.0 (Cq, COOH), 212.1 (Cq).
8-(P r op -2′-en yl)bicyclo[2.2.2]oct-5-en -2-on e (36). A dry
flask was filled with 50 mL of dry pyridine, and oxygen was
bubbled through it for 15 min. After addition of 800 mg (3.17
mmol) of 35 and 1.90 g (4.3 mmol) of lead tetraacetate, the
oxygen flow was kept over the solution and the flask was
immersed in an oil bath (85 °C). Evolution of gas was observed
immediately which ceased after 2 min. After an additional 5
min of heating, the mixture was cooled and poured into 10%
nitric acid. Extraction with ether, followed by washing the
combined organic layers with saturated sodium bicarbonate
solution and drying over magnesium sulfate, yielded 130 mg
(25%) of 36 after chromatography on silica (eluent: ch/ee 85:
15): IR (neat) 3020 cm-1, 2890, 1705 (s, CdO); 1H NMR (300
MHz, CDCl3) δ 1.33 (dddd, J ) 12.8, 5.2, 1.8, 0.7 Hz, 1 H, 7a-
H), 1.79 (m, 1 H, 8-H), 1.89 (dddd, J ) 12.8, 10.6, 3.7, 0.4 Hz,
1 H, 7b-H), 1.95 (dddd, J ) 18.8, 3.5, 1.7, 0.4 Hz, 1 H, 3a-H),
2.09 (ddddd, J ) 14.2, 7.2, 7.1, 1.3, 1.1 Hz, 1 H, 1′a-H), 2.21
(ddddd, J ) 14.1, 7.6, 6.6, 1.3, 1.1 Hz, 1 H, 1′b-H), 2.27 (ddd,
J ) 18.8, 2.3, 0.8 Hz, 1 H, 3b-H), 2.79 (ddddd, J ) 6.8, 3.5,
1.9, 1.7, 1.7 Hz, 1 H, 4-H), 3.07 (dddd, J ) 6.5, 3.4, 1.6, 1.5
Hz, 1 H, 1-H), 5.02 (dddd, J ) 10.1, 2.0, 1.1, 1.1 Hz, 1 H, 3′-H
cis), 5.05 (dddd, J ) 17.0, 2.0, 1.5, 1.5 Hz, 1 H, 3′-H trans),
5.77 (dddd, J ) 17.1, 10.1, 7.3, 6.4 Hz, 1 H, 2′-H), 6.15 (ddddd,
J ) 8.0, 6.5, 1.6, 0.8, 0.8 Hz, 1 H, 6-H), 6.58 (ddd, J ) 8.0, 6.6,
1.3 Hz, 1 H, 5-H); 13C NMR (90 MHz, CDCl3) δ 29.6 (CH2, C-7),
34.4 (CH2, C-3), 34.8 (CH, C-8), 36.0 (CH, C-4), 38.4 (CH2, C-1′),
48.9 (CH, C-1), 116.1 (CH2, C-3′), 127.6 (CH, C-6), 136.6 (CH,
C-2′), 139.0 (CH, C-5), 212.6 (Cq, C-2); MS (70 eV) m/ z 162
(M+, 5), 79 (100), 78 (48), 77 (31), 39 (32). An electrochemical
bisdecarboxylation of 900 mg (3.57 mmol) of 35 (solvent: 60
mL of pyridine, 0.81 mL of TEA, 8.5 mL of water, and 20 mg
of 2,6 di-tert-butylphenol) at carbon electrodes (2 × 4 cm, 200
V, 80 mA) gave the same product 36 in only 5% yield.
112 (M
+, 8), 111 (8), 97 (70), 95 (45), 94 (45), 79 (70), 70 (68),
67 (92), 55 (52), 44 (80), 41 (60), 39 (100). Anal. Calcd for
C7H12O: C, 74.95; H, 10.78. Found: C, 74.70; H, 10.95.
3,3-Dim eth ylcycloh exa n on e (5). The reaction of 655 mg
(5.28 mmol) of 2 and 560 mg (5.54 mmol) of TEA in 24 mL of
dry acetonitrile (procedure C) yielded 319 mg (48%) of 5 after
chromatography on silica (eluent: ch/ee 93:7): IR (neat) 2920
(s) cm-1, 2850, 1700 (s, CdO), 1440, 1360, 1285, 1215, 1070;
1H NMR (300 MHz, CDCl3) δ 0.98 (s, 6 H, CH3), 1.59 (t, J )
6.0 Hz, 2 H, 4-H), 1.88 (m, 2 H, 5-H), 2.15 (s, 2 H, 2-H), 2.26
(t, J ) 7.0 Hz, 2 H, 6-H); 13C NMR (75 MHz, CDCl3) δ 18.5
(CH2, C-5), 28.8 (CH3), 36.2 (Cq, C-3), 38.2 (CH2, C-4), 41.0
(CH2, C-2), 55.1 (CH2, C-6), 212.2 (Cq, C-1); MS (70 eV) m/ z
126 (M+, 4), 125 (8), 110 (8), 83 (100), 82 (10), 69 (20), 55 (40),
41 (30), 39 (42). Anal. Calcd for C8H14O: C, 76.14; H, 11.18.
Found: C, 75.94; H, 11.16.
8-Meth ylbicyclo[4.3.0]n on a n -3-on e (38). The PET reac-
tion (procedure C) of 600 mg (4.0 mmol) of 14 (6:1 mixture)
and 1.0 g (10.0 mmol) of TEA in 24 mL of dry acetonitrile
provided 40 mg of starting material and 130 mg of 38 (9:1
mixture) after purification using HPLC (eluent: ch/ee 9:1) in
23% yield based on conversion of 14. The spectroscopic data
6-(P r op -2′-en yl)tr icyclo[3.3.0.02,8]octa n -3-on e (37).
A
solution of 120 mg (0.74 mmol) of 36 in 12 mL of acetone was
degassed with argon and irradiated in a Rayonet photoreactor
at 300 nm using a quartz irradiation tube. After 3 h, the
starting material was completely converted and the solvent
was evaporated under reduced pressure. Compound 37 was
the only product and could be isolated after chromatography
on silica (eluent: ch/ee 85:15) in 58% yield: IR (neat) 3030
cm-1, 2930, 2900, 2840, 1710 (s, CdO); 1H NMR (360 MHz,
CDCl3) δ 1.15 (ddd, J ) 13.7, 11.2, 2.0 Hz, 1 H, 7a-H), 1.82-
2.13 (m, 6 H), 2.23 (dd, J ) 18.3, 9.3 Hz, 1 H, 4b-H), 2.42
(ddddd, J ) 11.2, 8.3, 8.1, 8.1, 5.3 Hz, 1 H, 6-H), 2.68 (ddd, J
) 6.0, 5.2, 5.1 Hz, 1 H, 1-H), 2.78 (ddd, J ) 9.4, 5.2, 5.2 Hz, 1
H, 5-H), 4.87-4.98 (m, 2 H, 3′-H), 5.66 (ddt, J ) 17.0, 10.1,
6.9 Hz, 1 H, 2′-H); 1H NMR (300 MHz, CDCl3/C6D6 1:1) δ 1.21
(ddd, J ) 13.7, 11.2, 2.0 Hz, 1 H, 7a-H), 1.85 (dddd, J ) 9.4,
6.6, 6.0, 2.0 Hz, 1 H, 8-H), 1.92 (dd, J ) 9.4, 5.1 Hz, 1 H, 2-H),
2.05 (dd, J ) 18.3, 0.9 Hz, 1 H, 4a-H), 2.00-2.10 (m, 2 H, 9-H),
2.11 (ddd, J ) 13.7, 8.3, 6.6 Hz, 1 H, 7b-H), 2.22 (dd, J ) 18.3,
9.5 Hz, 1 H, 4b-H), 2.42 (ddddd, J ) 11.2, 8.3, 8.1, 8.1, 5.3 Hz,
1 H, 6-H), 2.61 (ddd, J ) 6.0, 5.1, 5.1 Hz, 1 H, 1-H), 2.72 (dddd,
J ) 9.5, 5.3, 5.1, 0.9 Hz, 1 H, 5-H), 4.90-5.10 (m, 2 H, 3′-H),
5.73 (ddt, J ) 17.0, 10.1, 6.9 Hz, 1 H, 2′-H); 13C NMR (90 MHz,
CDCl3) δ 28.5 (CH, C-8), 30.4 (CH2, C-7), 34.6 (CH2, C-9), 36.5
(CH, C-1), 37.3 (CH, C-2), 40.0 (CH, C-5), 40.2 (CH2, C-4), 51.5
(CH, C-6), 115.4 (CH2, C-3′), 136.8 (CH, C-2′), 216.5 (Cq, C-3);
MS (70 eV) m/ z 163 (M+ + 1, 31) 162 (M+, 5), 91 (88), 79 (65),
78 (66), 39 (100), calcd for C11H14O 162.1044, found 162.1048.
1-(P en t -2′-en yl)-5-m et h yl-6-oxa b icyclo[3.1.0]h exa n -2-
on e (49). The epoxidation reaction (procedure B) of 1.15 g
(7.0 mmol) of cis-jasmone (27) yielded 600 mg (47%) of 49 after
chromatography on silica (eluent: pe/e 8:2): IR (neat) 3000
refer to the main isomer: IR (neat) 2920 (s) cm-1
, 2840, 1700
1
(s, CdO); H NMR (360 MHz, CDCl3) δ 0.74 (ddd, J ) 11.6,
11.6, 8.3 Hz, 1 H), 0.98 (d, J ) 7.0 Hz, 3 H, 10-H), 1.30-1.55
(m, 3 H, 5a-H), 1.60 (m, 2 H, 1-H, 6-H), 1.95-2.13 (m, 3 H,
2a-H, 5b-H), 2.15-2.24 (m, 2 H, 4-H, 8-H), 2.35 (dddd, J )
14.9, 4.9, 2.3, 2.1 Hz, 1 H, 4a-H), 2.48 (ddd, J ) 13.0, 2.3, 2.3
Hz, 1 H, 2b-H);
13C NMR (75 MHz, CDCl3) δ 23.1 (CH3, C-10),
29.7 (CH2, C-5), 32.5 (CH, C-8), 39.7 (CH2), 40.1 (CH2), 41.0
(CH2, C-4), 45.8/46.3 (2 × CH, C-1/C-6), 47.4 (CH2, C-2), 212.0
(Cq, C-3); MS (70 eV) m/ z 153 (M+ + 1, 8), 152 (M+, 6), 134
(54), 109 (35), 108 (100), 95 (80), 81 (53), 67 (72), 55 (60), 43
(46), 41 (69), 39 (94). Anal. Calcd for C10H16O: C, 78.89; H,
10.59. Found: C, 78.42; H, 10.69.
8-Meth ylbicyclo[4.3.0]n on a n -2-on e (40). The PET reac-
tion (procedure C) of 200 mg (1.33 mmol) of 26 and 530 mg
(5.3 mmol) of TEA in 12 mL of dry acetonitrile gave 30 mg of
starting material and 60 mg of 40 (2:1 mixture) after chro-
matography on silica (eluent: pe/e 7:3) in 35% yield based on
conversion of 26. The spectroscopic data were taken from the
mixture: IR (neat) 2920 (s) cm-1, 2860, 1700 (s, CdO); 1H NMR
(300 MHz, CDCl3) complex multiplet in the region of δ 1.2-
2.7, the signals of two methyl groups of the two diastereoiso-
mers could be assigned, main isomer δ 0.97 (J ) 6.9 Hz), minor
isomer δ 1.03 (J ) 6.2 Hz, the integrals of these signals were
used to determine the relative ratio of the two isomers); 13C
NMR (75 MHz, CDCl3) main isomer δ 22.2 (CH3), 23.9 (CH2),
27.9 (CH2), 31.5 (CH), 36.0 (CH2), 40.0 (CH2), 40.9 (CH2), 42.5
(CH), 53.1 (CH), 214.7 (Cq, C-2); 13C NMR (75 MHz, CDCl3)
minor isomer δ 21.0 (CH3), 23.1 (CH2), 28.5 (CH2), 33.7 (CH),
1
cm-1, 2940, 2850, 1725 (s, CdO); H NMR (300 MHz, CDCl3)

8894 J . Org. Chem., Vol. 61, No. 25, 1996
Kirschberg and Mattay
35.1 (CH2), 40.6 (CH2), 41.3 (CH2), 42.8 (CH), 53.1 (CH), 214.7
(Cq, C-2); MS (70 eV) m/ z 153 (M+ + 1, 10), 152 (M+, 50), 109
(41), 97 (40), 93 (34), 81 (100), 79 (25), 67 (45), 55 (28), 41 (48),
39 (82).
28.3 (Cq, C-8), 30.3 (CH2, C-11), 32.6 (CH2), 33.1 (CH2), 44.1
(CH, C-4), 44.6 (Cq, C-6), 87.5 (CH, C-3), 102.4 (Cq, C-1); MS
(70 eV) m/ z 179 (M+ + 1, 20), 163 (32), 161 (65), 149 (100),
131 (32), 121 (38), 107 (41), 105 (72), 95 (34), 93 (48), 91 (53),
81 (42), 79 (47), 67 (31), 55 (35), 53 (22), 41 (52), 39 (88), calcd
for C12H18O 178.1358, found 178.1359.
Bicyclo[4.3.0]n on a n -8-on e (39). The PET reaction (pro-
cedure C) of 100 mg (0.73 mmol) of 13 (9:1 mixture) and 370
mg (3.67 mmol) of TEA in 12 mL of dry acetonitrile yielded
20 mg (20%) of 39 after chromatography on silica (eluent: pe/e
Bicyclo[3.3.0]octa n -3-on e (6). The PET reaction (proce-
dure C) of 122 mg (1.0 mmol) of 3 and 505 mg (5.0 mmol) of
TEA in 12 mL of dry acetonitrile yielded 45 mg (26%) of 6 after
chromatography on silica (eluent: pe/e 8:2): IR (neat) 2920
1
8:2): IR (neat) 2910 (s) cm-1, 2840, 1735 (s, CdO); H NMR
(300 MHz, CDCl3) δ 1.11-1.25 (m, 2 H), 1.37 (m, 2 H), 1.57-
1.65 (m, 2 H), 1.78-1.87 (m, 4 H), 1.96 (m, 2 H), 2.33 (dd, J )
16.7, 6.2 Hz, 2 H); 13C NMR (75 MHz, CDCl3) δ 26.3 (CH2),
31.8 (CH2), 43.9 (CH, C-1, C-6), 45.6 (CH2, C-7, C-9), 218.2
(Cq); MS (70 eV) m/ z 139 (M+ + 1, 4), 138 (M+, 10), 137 (32),
109 (28), 96 (21), 95 (32), 94 (100), 81 (78), 67 (82), 54 (28), 41
(52), 39 (92). Anal. Calcd for C9H14O: C, 78.21; H, 10.21.
Found: C, 77.78; H, 10.82.
1
cm-1, 2840, 2820, 1720 (s, CdO); H NMR (300 MHz, CDCl3)
δ 1.32-1.42 (m, 2 H), 1.55-1.81 (m, 2 H), 1.86-2.01 (m, 4 H),
2.35-2.49 (m, 2 H), 2.65 (m, 2 H, 1-H, 5-H); 13C NMR (75 MHz,
CDCl3) δ 25.5 (CH2), 33.5 (CH2), 39.6 (CH, C-1, C-5), 44.6 (CH2,
C-2, C-4), 221.1 (Cq, C-3); MS (70 eV) m/ z 125 (M+ + 1, 8),
124 (M+, 6), 109 (5), 81 (30), 80 (32), 67 (100), 55 (20), 54 (22),
41 (26), 39 (52). Anal. Calcd for C8H12O: C, 77.37; H, 9.74.
Found: C, 77.14; H, 9.55.
2-Meth ylsp ir o[4.5]d eca n -7-on e (41). The PET reaction
(procedure C) of 850 mg (5.2 mmol) of 31 and 1.31 g (13.0
mmol) of TEA in 24 mL of dry acetonitrile yielded 352 mg of
41 (2:1 mixture) after purification using HPLC (eluent: ch/ee
85:15). The spectroscopic data were taken from the mixture:
8-Meth yltr icyclo[5.2.11,7.02,6]decan e-4-on e (44). The PET
reaction (procedure C) of 150 mg (0.92 mmol) of 37 and 1.01 g
(10.0 mmol) of TEA in 12 mL of dry acetonitrile yielded 40
mg (27%) of 44 after chromatography on silica (eluent: ch/ee
85:15): IR (neat) 2900 cm-1, 2840, 1725 (s, CdO), 1440, 1365,
1
IR (neat) 2930 (s) cm-1, 2860, 1710 (s, CdO); H NMR (300
1
MHz, CDCl3) signals in the region of δ 0.96-2.30, the methyl
proton signals were well separated, main isomer δ 0.97 (J )
7.0 Hz), minor isomer δ 0.98 (J ) 7.0 Hz); 13C NMR (75 MHz,
CDCl3) main isomer δ 20.7 (CH3), 23.8 (CH2), 33.4 (CH, C-2),
33.7 (CH2), 38.3 (CH2), 41.2 (CH2), 47.2 (CH2), 47.7 (Cq), 53.8
(CH2), 54.9 (CH2), 211.9 (Cq); MS (70 eV) m/ z 166 (M+, 30),
148 (18), 133 (24), 123 (100), 108 (28), 95 (38), 93 (28), 81 (52),
79 (24), 67 (60), 55 (36), 39 (59).
1160, 1060, 905; H NMR (360 MHz, C6D6) δ 0.58 (dddd, J )
12.1, 7.9, 4.3, 1.5 Hz, 1 H, 9a-H), 0.68 (d, J ) 6.1 Hz, 3 H,
11-H), 1.06 (ddddd, J ) 9.8, 1.7, 1.7, 1.7, 1.5 Hz, 1 H, 10a-H),
1.36 (ddd, J ) 9.8, 1.7, 1.5 Hz, 1 H, 10b-H), 1.41-1.48 (m, 2
H, 8-H, 9b-H), 1.58 (m, 1 H, 7-H), 1.80-1.98 (m, 5 H), 2.05-
2.18 (m, 2H, 2-H, 6-H); 13C NMR (90 MHz, C6D6) δ 22.3 (q,
J (CH) ) 128.8 Hz, C-11), 27.9 (d, J (CH) ) 125.5 Hz, C-8),
32.5 (t, J (CH) ) 125.5 Hz, C-9), 37.4 (t, J (CH) ) 126.0 Hz,
C-10), 37.6 (d, J (CH) ) 137.6 Hz, C-2), 38.8 (t, J (CH) ) 124.8
Hz, C-3/C-5), 39.2 (d, J (CH) ) 140.8 Hz, C-6), 42.0 (d, J (CH)
) 140.8 Hz, C-1), 48.2 (d, J (CH) ) 136.6 Hz, C-7), 217.5 (s,
C-4); MS (70 eV) m/ z 165 (M+ + 1, 18), 164 (M+, 10), 149 (8),
133 (6), 121 (16), 107 (35), 94 (37), 93 (49), 91 (32), 83 (74), 81
(92), 80 (100), 79 (50), 67 (48), 65 (21), 55 (13), 53 (24), 41 (31),
39 (83).
8-Meth ylsp ir o[5.5]u n d eca n -2-on e (42). The PET reac-
tion (procedure C) of 940 mg (5.28 mmol) of 32 and 1.31 g (13.0
mmol) of TEA in 24 mL of dry acetonitrile yielded 60 mg of 42
(3:1 mixture) after purification using HPLC (eluent: ch/ee 93:
7): The spectroscopic data were taken from the mixture: IR
(neat) 2940-2820 (s) cm-1, 1695 (s, CdO); 1H NMR (300 MHz,
CDCl3) all signals were in the region of δ 0.82-2.30; 13C NMR
(75 MHz, CDCl3) main isomer δ 14.5 (CH3), 21.6 (CH2), 32.4
(CH2), 35.3 (CH2), 36.0 (CH2), 36.6 (CH2), 39.3 (Cq), 40.4 (CH2),
41.4 (CH2), 44.1 (CH), 49.2 (CH2), 213.2 (Cq); MS (70 eV) m/ z
180 (M+, 24), 162 (27), 147 (15), 137 (100), 122 (47), 110 (38),
95 (69), 93 (32), 81 (45), 67 (57), 55 (47), 41 (62), 39 (68).
1-Meth yl-3-p r op ylbicyclo[3.3.0]octa n -6-on e (43). The
PET reaction (procedure C) of 810 mg (4.55 mmol) of 28 and
1.80 g (18.0 mmol) of TEA in 24 mL of dry acetonitrile yielded
320 mg of starting material, 70 mg (17% based on conversion
of 28) of 43, and 180 mg (34% based on conversion of 28) of
the oxetanes 45 and 46 after purification using HPLC (elu-
ent: ch/ee 93:7): IR (neat) 2951 cm-1, 2926, 2864, 1739 (s,
CdO); 1H NMR (360 MHz, CDCl3) δ 0.84 (m, 3 H, 3′-H), 1.18-
1.30 (m, 8 H), 1.45 (ddd, J ) 12.8, 11.1, 10.1 Hz, 1 H, 4a-H),
1.70-1.84 (m, 4 H), 2.03 (m, 1 H, 4b-H), 2.11 (dm, J ) 10.1
Hz, 1 H, 5-H), 2.24 (dddd, J ) 18.0, 8.2, 5.7, 0.8 Hz, 1 H, 7a-
H), 2.40 (dddd, J ) 18.0, 9.4, 9.4, 1.6 Hz, 1 H, 7b-H); 13C NMR
(75 MHz, CDCl3) δ 14.6 (CH3, C-3′), 22.0 (CH2, C-2′), 28.9 (CH3,
C-12), 35.4 (CH2, C-8), 37.1 (CH2, C-2 or C-4), 38.3 (CH2, C-1′),
39.2 (CH2, C-7), 40.3 (CH, C-3), 47.2 (Cq, C-1), 48.9 (CH2, C-2
oder C-4), 59.4 (CH, C-5), 223.4 (Cq, C-6); MS (70 eV) m/ z
181 (M+ + 1, 10), 180 (M+, 2), 97 (100), 95 (12), 81 (42), 67
(14), 55 (10), 39 (20), calcd for C12H20O 180.1514, found
180.1517. Anal. Calcd for C12H20O: C, 79.94; H, 11.18.
Found: C, 79.53; H, 11.06.
P h otolysis of cis-Ep oxyja sm on e (49). The PET reaction
(procedure C) of 150 mg (0.8 mmol) of 49 and 420 mg (4.1
mmol) of TEA in 12 mL of dry acetonitrile yielded 20 mg (15%)
of cis-jasmone (27) after chromatography on silica (eluent: pe/e
9:1). The spectroscopic data were identical with those of the
commercially available material.
Rea ction s w ith N-Silyla ted Am in es. 3,3-Dim eth yl-1-
[(tr im eth ylsilyl)oxy]cycloh exa n e (51). Irradiation (proce-
dure D) of 124 mg (1.0 mmol) of 2 and 117 mg (1.0 mmol) of
N,N-dimethyl(trimethylsilyl)amine in 12.0 mL of dry aceto-
nitrile yielded 45 mg (22%) of 51 after chromatography on
silica (eluent pe/e 9:1). The enol ether 50 was formed only in
a very small amount detectable by GLC: IR (neat) 2910 cm-1
,
2840, 1450, 1355, 1240 (s), 1075 (s), 1030, 945, 925, 900, 875,
830 (s), 740; 1H NMR (360 MHz, CDCl3) δ 0.01 (s, 9 H, OTMS),
0.86 (s, 3 H, 7-H), 0.90 (s, 3 H, 7′-H), 1.04 (ddd, J ) 13.1, 13.1,
4.2 Hz, 1 H, 4-H axial), 1.10 (dd, J ) 12.4, 12.6 Hz, 1 H, 2-H
axial), 1.13 (m, 1 H, 6-H axial), 1.25 (m, 1 H, 4-H equatorial),
1.38 (ddddd, J ) 13.4, 13.4, 13.4, 3.6, 3.6 Hz, 1 H, 5-H axial),
1.52 (dddd, J ) 12.6, 4.3, 2.1, 2.1 Hz, 1 H, 2-H), 1.58 (m, 1 H,
5-H), 1.78 (m, 1 H, 6-H equatorial), 2.96 (dddd, J ) 11.7, 11.7,
4.3, 4.3 Hz, 1 H, 1-H axial); 13C NMR (75 MHz, CDCl3) δ 0.0
(CH3, OTMS), 20.9 (CH2), 25.2 (CH3), 32.0 (Cq, C-3), 32.9 (CH3),
35.9 (CH2), 38.3 (CH2), 48.9 (CH2), 68.4 (CH, C-1); MS (70 eV)
m/ z 185 (45), 157 (52), 129 (20), 95 (18), 75 (100), 73 (40), 55
(10), 45 (16), 41 (22). Anal. Calcd for C11H24OSi: C, 65.92;
H, 12.07. Found: C, 65.72; H, 11.78.
3,3-Dim eth yl-1-[(tr im eth ylsilyl)oxy]cycloh ex-1-en e (50).
The irradiation (procedure D) of 340 mg (3.5 mmol) of 2 and
2.95 g (25.0 mmol) of N,N-dimethyl(trimethylsilyl)amine in
10.0 mL of dry acetonitrile yielded 230 mg (22 %) of 50 after
chromatography on silica (eluent: pe/e 8:2). The silyl ether
51 was formed only in a very small amount detectable by
GLC: IR (neat) 2930 cm-1, 2840, 1650, 1355, 1245 (s), 1205,
1135, 1030, 960, 875, 835 (s), 745; 1H NMR (360 MHz, CDCl3)
δ 0.12 (s, 9 H, OTMS), 0.95 (s, 6 H, 7-H), 1.30 (m, 2 H), 1.63
(m, 2 H, 5-H), 1.58 (dt, J ) 1.4, 6.5 Hz, 2 H), 4.62 (br s, 1 H,
2-H); 13C NMR (75 MHz, CDCl3) δ 0.0 (CH3, OTMS), 19.9
3-E t h y l-8-m e t h y l-2-o x a t e t r a c y c lo [4.4.0.01 ,4 .06 ,8 ]-
d eca n e (45). IR (neat) 2980-2920 (s) cm-1, 1460, 1440, 1380,
1320, 1285, 1240, 1185, 1130, 1110, 1095,1080, 1035, 1020,
1
1005, 970, 930, 905, 890, 850; H NMR (360 MHz, CDCl3) δ
0.61 (d, J ) 5.7 Hz, 1 H, 7a H), 0.90 (t, J ) 7.5 Hz, 3 H,
CH2CH3), 0.92 (d, J ) 5.7 Hz, 1 H, 7b-H), 1.08 (s, 3 H, CH3),
1.46 (ddd, J ) 15.0, 9.3, 9.3 Hz, 1 H, 10a-H), 1.50-1.80 (m, 3
H, 11-H, 9a-H), 1.88 (ddd, J ) 13.3, 9.5, 2.0 Hz, 1 H, 9b-H),
2.09 (ddd, J ) 15.0, 9.5, 2.3 Hz, 1 H, 10b-H), 2.25 (dd, J )
12.0, 6.5 Hz, 1 H, 5a-H), 2.44 (dd, J ) 12.0, 3.0 Hz, 1 H, 5b-
H), 2.90 (ddd, J ) 6.4, 2.1, 2.1 Hz, 1 H, 4-H), 4.42 (ddd, J )
6.4, 6.4, 2.1 Hz, 1 H, 3-H); 13C NMR (90 MHz, CDCl3) δ 8.4
(CH3, C-12), 19.6 (CH2, C-7), 20.4 (CH3, C-13), 28.0 (CH2, C-5),

Photoinduced Electron Transfer Reactions
J . Org. Chem., Vol. 61, No. 25, 1996 8895
(CH2), 29.8 (CH2), 30.5 (CH3, C-7), 31.7 (Cq, C-3), 36.9 (CH2),
115.8 (CH, C-2), 148.7 (Cq, C-1); MS (70 eV) m/ z 198 (M+,
20), 183 (75), 170 (38), 155 (20), 127 (42), 115 (20), 75 (72), 73
(100), 55 (18), 45 (26), 40 (34). Anal. Calcd for C11H22OSi: C,
66.59; H, 11.17. Found: C, 66.60; H, 11.18.
NMR (300 MHz, CDCl3) δ 0.45 (d, J ) 5.7 Hz, 1 H, 7a-H),
0.75 (t, J ) 7.4 Hz, 3 H, CH2CH3), 0.77 (d, J ) 5.7 Hz, 1 H,
7b-H), 0.96 (s, 3 H, 13-H), 1.28 (m, 1 H, 10a-H), 1.56 (m, 1 H,
9a-H), 1.65-1.84 (m, 3 H, 9b-H, 11-H), 1.89 (dd, J ) 12.4, 7.1
Hz, 1 H, 5a-H), 2.11 (ddd, J ) 14.8, 9.3, 2.1 Hz, 1 H, 10b-H),
2.52 (dd, J ) 12.4, 3.1 Hz, 1 H, 5b-H), 3.08 (ddd, J ) 6.4, 6.4,
3.3 Hz, 1 H, 4-H), 4.73 (ddd, J ) 6.9, 6.9, 6.7 Hz, 1 H, 3-H);
13C NMR (75 MHz, CDCl3) δ 8.8 (CH3, C-12), 18.9 (CH2, C-7),
20.1 (CH3, C-13), 20.3 (CH2), 24.6 (CH2), 28.0 (Cq, C-8), 31.1
(CH2), 32.5 (CH2), 41.5 (CH, C-4), 43.9 (Cq, C-6), 82.1 (CH,
C-3), 101.4 (Cq, C-1); MS (70 eV) m/ z 179 (M+ + 1, 16), no
M+, 163 (28), 161 (51), 149 (96), 131 (34), 121 (48), 107 (48),
105 (63), 95 (40), 93 (65), 91 (55), 81 (51), 79 (62), 67 (32), 55
(35), 53 (27), 41 (63), 39 (100).
Rea ction of 1-(P r op -2′-en yl)bicyclo[3.1.0]h exa n -2-on e
(25). A solution of 200 mg (1.5 mmol) of 25 in 12 mL of
benzene was placed in a Pyrex irradiation tube and degassed
with argon. The irradiation was performed in a Rayonet
photoreactor using 300 nm lamps. After complete disappear-
ance of the starting material, the reaction was stopped and
the solvent was removed under reduced pressure. The NMR
spectra of the crude material showed a ratio of 8:1 47/48 as
the only products. The products were separated using chro-
matography on silica (eluent: pe/e 7:3). One hundred mil-
ligrams (50%) of pure 47 and 10 mg (5%) of pure 48 were
isolated. Both compounds have a low boiling point and are
unstable, especially 48.
cis-1-(N ,N -Dim e t h yla ce t a m id o)-2-m e t h ylcyclop e n -
ta n e (52). The irradiation (procedure D) of 180 mg (1.47
mmol) of 3 and 176 mg (1.47 mmol) of N,N-dimethyl(trimeth-
ylsilyl)amine in 24.0 mL of dry acetonitrile yielded 80 mg (33%)
of 52 after chromatography on Al2O3 (eluent: ch/ee 85:15): IR
(neat) 2920 cm-1, 2864, 1630 (s, CdON), 1445, 1390, 1260,
1
1110; H NMR (300 MHz, C6D6) δ 0.77 (d, J ) 7.1 Hz, 3 H,
CH3), 1.21 (dddd, J ) 10.2, 8.5, 5.7, 5.0 Hz, 1 H, 3a-H), 1.32
(dddd, J ) 12.3, 9.3, 9.0, 7.1 Hz, 1 H, 5a-H), 1.49 (ddddd, J )
12.7, 9.5, 8.7, 7.1, 5.7 Hz, 1 H, 4a-H), 1.63 (ddddd, J ) 12.7,
9.3, 8.5, 6.0 4.2 Hz, 1 H, 4b-H), 1.73 (dddd, J ) 10.2, 9.5, 7.0,
6.0 Hz, 1 H, 3b-H), 1.87 (dddd, J ) 12.3, 8.7, 6.6, 4.2 Hz, 1 H,
5b-H), 1.92 (dd, J ) 15.5, 8.5 Hz, 1 H, 1′a-H), 2.09 (dd, J )
15.5, 6.6 Hz, 1 H, 1′b-H), 2.16 (dddq, J ) 7.0, 7.0, 5.0, 7.1 Hz,
1 H, 2-H), 2.24 (s, 3 H, N-CH3), 2.50 (ddddd, J ) 9.0, 8.5, 7.0,
6.6, 6.6 Hz, 1 H, 1-H), 2.68 (s, 3 H, N-CH3′); 13C NMR (75
MHz, C6D6) δ 15.4 (CH3), 22.7 (CH2, C-4), 30.3 (CH2, C-3), 33.3
(CH2, C-5), 34.1 (CH2, C-1′), 35.4 (N-CH3), 36.1 (CH, C-2), 37.4
(N-CH3′), 39.6 (CH, C-1), 173.1 (Cq, CON); MS (70 eV) m/ z
170 (M+ + 1, 100), 169 (M+, 3), 154 (12), 126 (12), 87 (65), 72
(82), 55 (32), 45 (52), 44 (48), 39 (38).
cis-1-(N,N-Diet h yla cet a m id o)-2-m et h ylcyclop en t a n e
(53). The irradiation (procedure D) of 122 mg (1.0 mmol) of 3
and 145 mg (1.0 mmol) of N,N-diethyl(trimethylsilyl)amine in
12.0 mL of dry acetonitrile yielded 70 mg (35%) of 53 after
chromatography on Al2O3 (eluent: ch/ee 85:15): IR (neat) 2920
Ma in isom er 47, (2-oxa tetr a cyclo[4.4.0.01,4.06,8]d eca n e):
IR (neat) 2960 cm-1, 2910 (s), 2850 (s), 1435, 1302, 1220, 1165,
1085, 1037, 1020, 960, 918, 750; 1H NMR (300 MHz, CDCl3) δ
0.79 (dd, J ) 5.7, 5.7 Hz, 1 H, 7a-H), 0.97 (dd, J ) 8.1, 5.7 Hz,
1 H, 7b-H), 1.23 (m, 1 H), 1.45 (ddd, J ) 15.0, 8.8, 8.8 Hz, 1 H,
10a-H), 1.72 (dddd, J ) 13.9, 9.3, 2.4, 0.7 Hz, 1 H, 9b-H), 2.03
(m, 1 H), 2.26 (ddd, J ) 15.0, 9.8, 2.4 Hz, 1 H, 10b-H), 2.40
(ddd, J ) 12.0, 5.3, 1.2 Hz, 1 H, 5a-H), 2.70 (dd, J ) 12.1, 2.9
Hz, 1 H, 5b-H), 3.31 (m, 1 H, 4-H), 4.54 (dd, J ) 6.2, 2.4 Hz,
1 H, 3a-H), 4.87 (ddd, J ) 6.2, 6.2, 1.4 Hz, 1 H, 3b-H); 13C
NMR (75 MHz, CDCl3) δ 13.7 (CH2, C-5), 25.8 (CH, C-4), 26.3
(CH2), 31.8 (CH2), 32.8 (CH2), 39.3 (CH, C-8), 40.8 (Cq, C-6),
75.8 (CH2, C-9), 106.3 (Cq, C-1).
1
cm-1, 2850, 1625 (s, CdON), 1415, 1370, 1240, 830; H NMR
(300 MHz, CDCl3) δ 0.76 (d, J ) 7.1 Hz, 3 H, CH3), 1.03 (t, J
) 7.1 Hz, 3 H, NCH2CH3), 1.11 (t, J ) 7.1 Hz, 3 H, NCH2CH3′),
1.15-1.80 (m, 6 H), 2.00-2.16 (m, 2 H), 2.21-2.35 (m, 2 H),
3.26 (q, J ) 7.1 Hz, 2 H, N-CH2CH3), 3.31 (dq, J ) 7.1, 2.4
Hz, 2 H, N-CH2′CH3); 13C NMR (75 MHz, CDCl3) δ 13.0 (CH3),
14.4 (CH3), 15.3 (CH3), 22.6 (CH2), 30.1 (CH2), 33.4 (CH2), 33.7
(CH2), 35.9 (CH), 40.0 (CH), 41.9 (CH2), 44.6 (CH2), 173.1 (Cq,
C-7); MS (70 eV) m/ z 198 (M+ + 1, 100), 197 (M+, 3), 182 (12),
154 (12), 115 (82), 100 (100), 72 (48), 58 (72), 55 (45), 44 (46),
41 (42), 39 (32).
Min or isom er 48, (9-oxa tetr a cyclo[6.1.1.0.3,50.3,8]d eca n ):
1H NMR (300 MHz, CDCl3) δ 0.52 (dd, J ) 5.3, 5.0 Hz, 1 H,
5a H), 0.81-0.93 (m, 1 H), 0.97 (dd, J ) 8.3, 5.5 Hz, 1 H, 5b-
H), 1.34 (ddd, J ) 14.9, 9.3, 6.9 Hz, 1 H, 2a-H), 1.59-1.71 (m,
1 H, 3a-H), 2.09 (m, 1 H), 2.29 (ddd, J ) 14.8, 10.3, 3.9 Hz, 1
H, 2b-H), 2.57 (dd, J ) 13.1, 4.0 Hz, 1 H, 7a-H), 2.75 (d, J )
13.1 Hz, 1 H, 7b-H), 4.77 (d, J ) 6.2 Hz, 1 H, 10a-H), 4.97 (dd,
J ) 6.2, 1.2 Hz, 1 H, 10b-H), 5.31 (br d, J ) 4.0 Hz, 1 H, 8-H);
13C NMR (75 MHz, CDCl3) δ 16.0 (CH2, C-5), 27.4 (CH, C-4),
29.3 (CH2), 32.2 (CH2), 37.5 (CH2), 38.2 (Cq, C-6), 59.6 (Cq,
C-1), 78.6 (CH2, C-10), 88.5 (CH, C-8).
N,N-Dim eth yl-2-acetyl-(Z)-h ept-4-en oic Am ide (55). The
irradiation (procedure D) of 360 mg (2.0 mmol) of 49 and 1.17
g (10.0 mmol) of N,N-dimethyl(trimethylsilyl)amine in 24.0 mL
of dry acetonitrile yielded 150 mg (44%) of 55 after chroma-
tography on Al2O3 (eluent: ch/ee 6:4): IR (neat) 2950 cm-1
,
2860, 1710 (s, CdO), 1620 (s, CdON), 1395, 1250, 965; 1H
NMR (300 MHz, CDCl3) δ 0.92 (t, J ) 7.6 Hz, 3 H, CH2CH3),
2.02 (m, 2 H, CH2CH3), 2.11 (s, 3 H, 2′-H), 2.60 (br t, J ) 7.3
Hz, 2 H, 3-H), 2.96 (s, 3 H, N-CH3), 3.02 (s, 3 H, N-CH3′),
3.55 (t, J ) 7.2 Hz, 1 H, 2-H), 5.18 (dtt, J ) 10.9, 7.2, 1.5 Hz,
1 H, 4-H), 5.41 (dtt, J ) 10.9, 7.1, 1.2 Hz, 1 H, 5-H); 13C NMR
(75 MHz, CDCl3) δ 14.1 (CH3, C-7), 20.4 (CH2), 26.8 (CH3, C-2′),
27.0 (CH2), 35.2 (N-CH3), 36.9 (N-CH3′), 57.8 (CH, C-2), 124.4
(CH), 134.3 (CH), 168.8 (Cq, C-1), 204.2 (Cq, C-1′); MS (70 eV)
m/ z 198 (M+ + 1, 43), 197 (M+, 5), 182 (4), 154 (100), 129 (12),
109 (24), 81 (21), 72 (81), 55 (10), 45 (21), 44 (32), 43 (47), 39
(23).
Rea ction s in th e P r esen ce of Meth a n ol. 2-Acetyl-(Z)-
h ep t-4-en oic a cid m eth yl ester (54a ). The irradiation
(procedure D) of 180 mg (1.0 mmol) of 49 and 1.0 mL (24.0
mmol) of methanol in 12.0 mL of dry acetonitrile yielded 55
mg (29%) of 54a and 20 mg (11%) of 56a after chromatography
on silica (eluent: ch/ee 85:15): IR (neat) 2950 cm-1, 2860, 1790,
1
1730, 1705, 1430, 1350, 1165, 1120, 965; H NMR (300 MHz,
CDCl3) δ 0.90 (t, J ) 7.1 Hz, 3 H, CH2CH3), 1.90-2.07 (m, 2
H), 2.18 (s, 3 H, 2′-H), 2.42-2.65 (m, 2 H), 3.34 (m, 1 H), 3.70
(s, 3 H, OCH3), 5.11-5.31 (m, 2 H); 13C NMR (75 MHz, CDCl3)
δ 13.7 (CH3, C-7), 25.4 (CH2), 29.1 (CH3, C-2′), 31.4 (CH2), 52.3
(CH3, OCH3), 59.7 (CH, C-2), 124.3 (CH), 135.5 (CH), 169.9
(Cq, C-1), 202.7 (Cq, C-1′); MS (70 eV) m/ z 185 (M+ + 1, 12),
184 (M+, 28), 152 (8), 141 (30), 109 (32), 95 (29), 81 (72), 67
(27), 55 (15), 43 (100), 39 (33). Anal. Calcd for C10H16O3: C,
65.19; H, 8.75. Found: C, 65.30; H, 8.64.
In tr a m olecu la r Oxeta n e F or m a tion s. Rea ction of
5-Meth yl-1-(p en t-2′-en yl)bicyclo[3.1.0]h exa n -2-on e (28).
A solution of 250 mg (1.4 mmol) of 28 in 12 mL of benzene
was placed into a Pyrex irradiation tube and degassed with
argon. The irradiation was performed in a Rayonet photore-
actor using 300 nm lamps. After complete disappearance of
the starting material, the reaction was stopped and the solvent
was evaporated under reduced pressure. The NMR spectrum
of the crude material showed a ratio of 3.2:1, 45/46 as the only
products. The products were separated using HPLC (eluent:
ch/ee 93:7). Ninety milligrams (36%) of pure 45 and 15 mg
(6%) of pure 46 were isolated. Both compounds have a low
boiling point and are quite unstable.
1-Met h yl-2-(m et h oxyca r b on yl)-6-et h yl-5-oxa b icyclo-
[2.1.1]h exa n e (56a ): IR (neat) 2960 cm-1, 2910 (s), 2850 (s),
1
1435, 1302, 1220, 1165, 1085, 1037, 1020, 960, 918, 750; H
NMR (300 MHz, CDCl3) δ 0.77 (t, J ) 7.4 Hz, 3 H, CH2CH3),
0.97-1.10 (m, 2 H, CH2CH3), 1.44 (s, 3 H, CH3), 2.10 (dd, J )
12.0, 8.4 Hz, 1 H, 3a-H), 2.33 (ddt, J ) 3.5, 1.4, 7.4 Hz, 1 H,
6-H), 2.39 (dddd, J ) 11.9, 4.0, 2.6, 1.4 Hz, 1 H, 3b-H), 2.80
(dd, J ) 8.6, 4.3 Hz, 1 H, 2-H), 3.68 (s, 3 H, OCH3), 4.43 (dd,
J ) 3.3, 2.6 Hz, 1 H, 4-H); 13C NMR (75 MHz, CDCl3) δ 11.1
Ma in isom er 45: spectroscopic data identical with those
of compound 45 isolated after the PET reaction.
Min or isom er 46: IR (neat) 2950 cm-1, 2910 (s), 2840, 1450,
1430, 1370, 1280, 1105, 1085, 1030, 960, 930, 900, 880; 1H

8896 J . Org. Chem., Vol. 61, No. 25, 1996
Kirschberg and Mattay
1
(CH3, C-8), 17.8 (CH3, C-9), 19.0 (CH2, C-7), 32.6 (CH2, C-3),
45.9 (CH), 51.7 (CH3, C-11), 58.6 (CH), 81.1 (CH, C-4), 94.0
(Cq, C-1), 174.1 (Cq, C-10); MS (70 eV) m/ z 184 (M+, 8), 167
(6), 166 (42), 152 (12), 141 (34), 125 (48), 109 (48), 107 (34), 95
(49), 81 (68), 79 (22), 67 (37), 59 (12), 55 (46), 53 (27), 43 (100),
41 (47), 39 (62), calcd for C10H16O3 184.1099, found 184.1096.
2-Acetyl-(Z)-h ep t-4-en oic Acid Tr id eu ter iom eth yl Es-
ter (54b). The irradiation (procedure D) of 180 mg (1.0 mmol)
of 49 and 1.0 mL (24.0 mmol) of methanol-d-4 in 12.0 mL of
dry acetonitrile yielded 66 mg (34%) of 54b and 25 mg (13%)
of 56b after chromatography on silica (eluent: ch/ee 85:15):
IR (neat) 2940 cm-1, 2910, 2850, 1730 (s), 1700, 1450, 1345,
1215, 1075, 960; 1H NMR (300 MHz, CDCl3) δ 0.89 (t, J ) 7.4
Hz, 3 H, CH2CH3), 1.88-2.07 (m, 2 H), 2.18 (s, 3 H, 2′-H),
2.42-2.65 (m, 2 H), 3.42 (t, J ) 7.4 Hz, 1 H, 2-H), 5.13-5.32
(m, 1 H), 5.35-5.54 (m, 1 H); 13C NMR (75 MHz, CDCl3) δ 13.7
(CH3, C-7), 25.4 (CH2), 28.8 (CH3, C-2′), 31.2 (CH2), 59.4 (CH,
C-2), 124.3 (CH), 134.8 (CH), 169.9 (Cq, C-1), 202.6 (Cq, C-2′);
MS (70 eV) m/ z 188 (M+ + 1, 32), 187 (M+, 57), 144 (38), 125
(12), 120 (12), 109 (50), 95 (41), 81 (91), 68 (29), 67 (28), 55
(14), 53 (16), 43 (100), 41 (26), 39 (41).
965, 860, 840; H NMR (300 MHz, CDCl3) δ 0.78 (t, J ) 7.4
Hz, 3 H, CH2CH3), 0.97-1.11 (m, 2 H, CH2CH3), 1.42 (s, 3 H,
9-H), 2.07 (dt, J ) 12.1, 1.4 Hz, 1 H, 3a-H), 2.30-2.43 (m, 2
H, 6-H, 3b-H), 4.43 (dd, J ) 3.3, 2.4 Hz, 1 H, 4-H); 13C NMR
(75 MHz, CDCl3) δ 11.1 (CH3, C-8), 17.7 (CH3, C-9), 18.9 (CH2,
C-7), 32.5 (CH2, C-3), 45.9 (small signal, CD), 58.3 (CH, C-6),
81.1 (CH, C-4), 94.8 (Cq, C-1), 173.7 (Cq, C-10); MS (70 eV)
m/ z 188 (M+, 20), 187 (21), 170 (100), 145 (53), 129 (87), 109
(67), 108 (91), 96 (80), 82 (52), 68 (29), 56 (18), 54 (23), 43 (71),
41 (32), 39 (58).
Ack n ow led gm en t. Th. Kirschberg acknowledges
the Deutsche Forschungsgemeinschaft (DFG) for a
predoctoral fellowship (Graduate College “Highly Reac-
tive Multiple Bonds”). J . Mattay thanks the DFG, the
Volkswagen-Stiftung, the state Northrhine-Westfalia,
the Fonds der Chemischen Industrie, Bayer AG, Her-
aeus GmbH, and Philips Bildro¨hrenwerke for financial
support and donations of chemicals and lamps. We also
gratefully acknowledge Ralf Hoffmann’s proficient as-
sistance in preparing the manuscript.
1-Meth yl-2-deu ter io-2-[(tr ideu ter iom eth oxy)car bon yl]-
6-eth yl-5-oxa bicyclo[2.1.1]h exa n e (56b): IR (neat) 2950
cm-1, 2920, 2860, 1720, 1450, 1375, 1300, 1270, 1150, 1085,
J O961015B