Oxidative dearomatization and unusual intramolecular Diels-Alder reaction of cyclohexa-2,4-dienone: Synthesis and photoreaction of oxa-tricyclo[5.2.2.01,5]undec-10-ene-8-ones

Article abstract of DOI:10.1016/j.tetlet.2015.02.113

Abstract An efficient synthesis of annulated bicyclo[2.2.2]octane having β,γ-enone chromophoric system and triplet sensitized 1,2-acyl shift rearrangement leading to the formation of angular oxa-triquinane is described. Oxidative dearomatization, intramolecular Diels-Alder reaction of 6,6-spiroepoxycyclohexa-2,4-dienone and oxa-di-π-methane reaction are the key features of our approach.

Full text of DOI:10.1016/j.tetlet.2015.02.113

Tetrahedron Letters 56 (2015) 1982–1985
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Oxidative dearomatization and unusual intramolecular Diels–Alder
reaction of cyclohexa-2,4-dienone: synthesis and photoreaction of
oxa-tricyclo[5.2.2.01,5]undec-10-ene-8-ones
⇑
Vishwakarma Singh , Beauty Das
Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400 076, India
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient synthesis of annulated bicyclo[2.2.2]octane having b,c-enone chromophoric system and
triplet sensitized 1,2-acyl shift rearrangement leading to the formation of angular oxa-triquinane is
described. Oxidative dearomatization, intramolecular Diels–Alder reaction of 6,6-spiroepoxycyclohexa-
Received 30 December 2014
Revised 19 February 2015
Accepted 20 February 2015
Available online 5 March 2015
2,4-dienone and oxa-di-
p
-methane reaction are the key features of our approach.
Ó 2015 Elsevier Ltd. All rights reserved.
Keywords:
Oxidative dearomatization
Cyclohexa-2,4-dienones
Intramolecular Diels–Alder reaction
Oxa-di-p-methane rearrangement
Photochemistry
Introduction
hexa-2,4-dienones and chemistry of their adducts in ground and
excited states.6 In view of the above and our continuing interest
in this area we considered exploring intramolecular cycloaddition
in spiroepoxycyclohexa-2,4-dienone 2 having an olefinic tether at
C-5 with a view to devise a route to tricyclic compounds of type
3 (Fig. 1) and examine their photoreaction.
Rapid creation of molecular complexity is one of the important
aspects in designing synthesis and development of methods.1
Tandem/cascade reactions and multi-component reactions are
often employed to achieve this objective.2 Recently, there has been
an upsurge of interest in oxidative dearomatization of phenols and
While there are no methods for the synthesis of tricyclic
the resulting intermediates such as
a
,a-dialkoxycyclohexa-2,
compounds of type 3, only a few routes are available to
4-dienones, -hydroxy-cyclohexa-2,4-dienone and spiroepoxy-
a
simple bicyclo[2.2.2]octenones. Generally, Diels–Alder reaction of
cyclohexa-1,3-diene and its derivatives with electron deficient
dienophiles and ketene equivalents is employed for the synthesis
of bicyclo[2.2.2]octanes.10 However, there are various limitations
due to inaccessibility of substituted cyclohexa-1,3-dienes and their
reactivity.
We wish to report herein oxidative dearomatization of o-hy-
droxymethyl phenol 1 to spiroepoxycyclohexadienone 2 and its
intramolecular cycloaddition leading to efficient synthesis of
tricyclic compounds of type 3 and its photochemical reaction upon
triplet excitation.
cyclohexa-2,4-dienones as the chemistry of these species has
proved to be a powerful method for efficient generation of complex
molecular architectures.3–6
Functionalized and annulated bicyclo[2.2.2]octane ring systems
have stimulated considerable interest because of their synthetic
potential as they undergo various types of regio- and stereoselec-
tive transformations by virtue of their rigid framework and the
interactions among the functional groups.7,8 Moreover, the pres-
ence of bicyclo[2.2.2]octane framework in many biologically active
natural products such as crotogoudin,9a maoecrystal9b and
others,9c–f has further enhanced the interest in their synthesis.
We have
a longstanding interest in the development of
Results and discussion
methodology employing cycloaddition of 6,6-spiroepoxycyclo-
Thus, the aromatic precursor 1 was readily prepared as shown
in Scheme 1. 2,3-Dimethyl phenol 4a was easily converted into
acetonide
5 in a few routine steps according to a known
⇑
Corresponding author. Fax: +91 22 2572 3480.
E-mail address: vks@chem.iitb.ac.in (V. Singh).
procedure.11 O-allylation of compound 5 with allyl bromide and
http://dx.doi.org/10.1016/j.tetlet.2015.02.113
0040-4039/Ó 2015 Elsevier Ltd. All rights reserved.

V. Singh, B. Das / Tetrahedron Letters 56 (2015) 1982–1985
1983
Figure 1. Spiroepoxycyclohexadienone 2 and tricyclic compound 3.
sodium hydride followed by hydrolysis of acetonide gave the aro-
matic precursor 1 in excellent yield (Scheme 1).
The aromatic precursor 1 was subjected to a tandem oxidative
dearomatization and intramolecular cycloaddition. Thus, a solution
of compound 1 in CH2Cl2 containing cetyltrimethylammonium
bromide (CTAB) as a phase transfer catalyst was treated with
aqueous solution of sodium metaperiodate at 0–5 °C following a
procedure earlier developed12 in our group. Usual work-up and
chromatography gave adduct 6 as a major product along with
the unreacted spiroepoxycyclohexa-2,4-dienone 2 (Scheme 2). It
was remarkable to note that spiroepoxycyclohexadienone 2 was
quite stable and could be thoroughly characterized. This is in con-
trast to the general behaviour of spiroepoxycyclohexadienones
because these species are very reactive and undergo instantaneous
dimerization.13
Scheme 2. Oxidative dearomatization and intramolecular cycloaddition.
(m, 1H) and 1.78 (dd, J1 = 13.5 Hz, J2 = 7.5 Hz, 1H). The proton at
the tetrahydrofuran ring junction appeared at d 2.39–2.27 (m,
1H). These assignments were made with the help of a COSY spec-
trum wherein the signal at d 3.49–3.45 exhibited correlation with
olefinic proton at d 6.23 and signals at d 2.17–2.03, 1.78. Further,
the multiplet at d 2.39–2.27 showed correlation with the signals
at d 2.17–2.03 (m, 1H), 1.78 (assigned to methylene protons adja-
cent to the bridgehead) and d 4.08 and 3.62 (assigned to oxymethy-
lene protons adjacent to the ring junction) respectively. The
Interestingly, heating cyclohexadienone 2 in benzene followed
by chromatography gave two adducts, epoxy adduct 6 as a major
13C NMR (100 MHz, CDCl3) spectrum of adduct
6 exhibited
characteristic signals at d 204.2 and 137.8, 127.4 for carbonyl and
olefinic carbons, respectively. In addition, signals were shown at
d 70.4, 67.2, 56.6, 52.1, 47.9, 47.5, 44.9 and 22.3 for other carbons.
These spectral features suggested the gross structure of adduct 6.
However, it was difficult to fully ascertain the stereochemical
orientation of the tetrahydrofuran ring in compound 6 from the
product and the isomeric adduct
7 as a minor product
(Scheme 2). The structure of adducts was deduced as follows.
IR spectrum of the major adduct 6 showed an absorption band
at 1734 cmÀ1 for the carbonyl group. 1H NMR (400 MHz, CDCl3)
spectrum of adduct 6 displayed characteristic signals at d 6.65
(doublet with structure, J = 8.3 Hz, 1H) and 6.23 (dd, J1 = 8.3 Hz,
spectral data alone. Hence,
a single-crystal X-ray structure
J2 = 7.0 Hz, 1H) for the c- and b-olefinic protons of b,c-enone moi-
determination of compound 6 was undertaken (Fig. 2) which con-
ety, respectively. Interestingly, protons of one of the oxymethylene
groups (adjacent to the bridgehead) of the tetrahydrofuran ring
appeared as a singlet at d 3.76 (s, 2H). The protons of the other
oxy-methylene group present in tetrahydrofuran ring system
appeared at d 4.08 (merged dd, J1 = J2 = 7.6 Hz, 1H), and 3.62 (dd,
J1 = 12.1 Hz, J2 = 7.6 Hz, 1H) due to coupling with each other and
the vicinal proton at the ring junction. The methylene protons of
the oxirane ring showed characteristic signals at d 2.94 (part of
an AB system, J = 5.8 Hz, 1H) and 2.79 (part of an AB system,
J = 5.8 Hz, 1H). The proton at the bridgehead appeared at d 3.49–
3.45 (m, 1H) whereas methylene protons adjacent to the bridged
head carbon having proton exhibited signals at d 2.17–2.03
firmed the structure and stereochemistry.14
The structure and stereochemistry of the minor adduct 7 was
deduced from its spectral characteristics, COSY spectrum and com-
parison with the spectral features of adduct 6 as follows. Thus, 1H
NMR spectrum of adduct 7 displayed signals for two olefinic
protons at d 6.50 (merged dd, J1 = J2 = 8.0 Hz, 1H) and 6.32
(d, J = 8.0 Hz, 1H). The oxymethylene protons of the oxirane ring
appeared as usual at d 3.10 (part of an AB system, J = 5.7 Hz, 1H)
and 2.68 (part of an AB system, J = 5.7 Hz, 1H). Interestingly in this
case, the oxymethylene protons of the tetrahydrofuran ring exhib-
ited four distinct resonances. The oxymethylene protons adjacent
Scheme 1. Preparation of aromatic precursor 1.
Figure 2. Crystal structure of compound 6.

1984
V. Singh, B. Das / Tetrahedron Letters 56 (2015) 1982–1985
to the bridgehead (quaternary) appeared as AB system at d 3.88
(part of an AB system, J = 7.9 Hz, 1H), 3.62 (part of an AB system,
J = 7.9 Hz, 1H) whereas the signals at
d 4.05 (merged dd,
J1 = J2 = 7.7 Hz, 1H) and 3.22 (dd, J1 = 11.1 Hz, J2 = 7.7 Hz, 1H) were
assigned to the oxymethylene protons adjacent to the ring junction
as these correlate with each other and also with the multiplet at d
2.82–2.71 (assigned to the ring junction proton) (Fig. 3). Further,
the multiplet at d 3.35–3.30 was assigned to the bridgehead proton
as it showed COSY with the olefinic proton at d 6.50. The multiplets
at d 2.28 (merged ddd, J1 = 12.8 Hz, J2 = 9.5 Hz, J3 = 3.4 Hz, 1H) and
1.49 (dd with structure, J1 = 12.8 Hz, J2 = 7.2 Hz, 1H) were assigned
to the methylene protons of the bicyclo[2.2.2]octane framework as
these correlated with each other and with the signal at d 2.82–2.71
(assigned to the ring junction proton of the tetrahydrofuran ring).
Further, the multiplet at d 2.28 also showed COSY with the bridge-
head proton. A comparison of the above features especially the
downfield chemical shift of the ring junction proton in adduct 7
(d 2.82–2.71) with that of the adduct 6 wherein the ring junction
proton appears at relatively high field (d 2.39–2.27) suggested
the stereochemistry of the adduct 7 (endo).
Scheme 3. Transformation of adduct 6.
1H). 13C NMR (100 MHz, CDCl3) spectrum also supported the above
formulation as it showed signals at d 212.0 and 208.4 for the two
carbonyl groups. The olefinic carbons exhibited signals at d 143.4
and 123.1. In addition, signals were displayed at d 70.7, 70.2,
56.5, 52.9, 50.2, 49.6, 46.6, 32.6, 23.4 and 21.3 due to other carbons.
After having prepared tricyclic systems 9 and 10 having a
It was indeed a surprise to note the formation of adduct 6 hav-
ing exo-stereochemistry as a major product and endo-adduct 7 as a
minor product in the aforementioned
especially since intramolecular cycloaddition in cyclohexa-2,4-die-
p p
4s + 2s cycloaddition
b,c-enone chromophore, we examined their photoreaction upon
nones having
a six-carbon tether at C-5 is known to give
sensitized irradiation. Photochemical reactions of rigid b,c-enones
endo-adducts.15 In this case, it appears that exo-transition state is
more favored compared to the transition state leading to endo-adduct
due to geometrical factors involved in the formation of the
tetrahydrofuran ring.
have stimulated interest for quite some time17 that has enhanced
recently because of their synthetic potential.18,19 In general, sensi-
tized irradiation of b,c-enones leads to oxa-di-p-methane reaction
or 1,2-acyl shift whereas direct irradiation (1S) leads to a 1,3-acyl
shift. These reactions are quite characteristic of excited states,
however, structure of the substrate and functional group often
control the reaction in a subtle fashion. Keeping the above in mind
we examined the photoreaction of 9 and 10 upon sensitized
irradiation.
Thus, a solution of compound 9 in acetone (both as a solvent
and sensitizer) was irradiated in a Pyrex immersion well for 1.5 h
under nitrogen. Removal of solvent followed by chromatography
furnished the tetracyclic compound 11 (Scheme 4) as a result of
The presence of keto-epoxide functionality in adducts provided a
unique opportunity for manipulation. Treatment of 6 with Zn-NH4Cl
in refluxing dioxane gave the compound 8 (mixture of syn:anti iso-
mers) as a major product as a result of deoxygenation of the oxirane
ring. Alkylation of compound 8 with allyl bromide in the presence of
NaH–THF gave the tricyclic compound 9 in good yield (82%) as a
result of stereoselective alkylation. Such type of stereoselective
alkylation in bicyclo[2.2.2]octenones is well known.16 Wacker oxi-
dation of compound 9 provided the tricyclic dione 10 having a
b,c-enone chromophore (Scheme 3). The structures of all the com-
pounds were supported from their spectral features.
Thus, IR spectrum of the compound 10 showed an absorption
band at 1719 cmÀ1 for carbonyl groups. 1H NMR (400 MHz,
CDCl3) spectrum of the compound 10 displayed characteristic
oxa-di-
stereochemistry of the compound 11 in which the tetrahydrofuran
ring is fused to the five-membered ring in trans-fashion.
p-methane reaction. It is interesting to note the
a
Generally, carbocyclic five membered rings prefer to fuse with each
other in a cis-fashion, a few examples of oxa-polyquinanes and
diquinanes having trans-fusion are known.20
Sensitized irradiation of compound 10 having an additional car-
bonyl group in addition to the b,c-enone chromophore did not lead
signals at
J1 = J2 = 7.9 Hz, 1H) for the b- and
d
6.53 (d, J = 7.9 Hz, 1H) and 5.96 (merged dd,
-olefinic protons of the b,c-
c
eneone moiety, respectively. Oxymethylene protons of the tetrahy-
drofuran ring showed signals at d 4.38 (part of an AB system,
J = 9.6 Hz, 1H), 4.04 (merged dd, J1 = J2 = 8.2 Hz, 1H), 3.80 (part of
an AB system, J = 9.6 Hz, 1H) and 3.69 (dd, J1 = 11.2 Hz,
J2 = 8.2 Hz, 1H). The methyl group of COCH3 moiety appeared at d
2.01 (s, 3H) whereas the methyl group at quaternary centre
showed signal at d 1.35 (s, 3H). In addition, other resonances were
shown at d 3.45 (merged dd, J1 = J2 = 5.5 Hz, 1H), 2.66 (part of an AB
system, J = 12.3 Hz, 1H), 2.39 (part of an AB system, J = 12.3 Hz,
1H), 2.37–2.29 (m, 1H), 1.98–1.89 (m, 1H) and 1.83–1.75 (m,
δ 2.82-2.71 (m)
H
O
H
O
O
δ 6.32
H
4.05 &
3.22
}
δ
H
H
H
H
δ 6.50
}
δ
H
2.28 &
1.49
3.35-
3.30
δ
Figure 3. Key correlations in the COSY spectrum of compound 7.
Scheme 4. Photochemical reaction and other transformations.

V. Singh, B. Das / Tetrahedron Letters 56 (2015) 1982–1985
1985
Krawczuk, P. J.; Schone, N.; Baran, P. S. Org. Lett. 2009, 11, 4774–4776; (d) Gong,
J.; Lin, J.; Sun, W.; Li, C. C.; Yang, Z. J. Am. Chem. Soc. 2010, 132, 16745–16746;
(e) Constantin, M. A.; Conrad, J.; Merisor, E.; Koschorreck, K.; Urlacher, V. B.;
Beifuss, U. J. Org. Chem. 2012, 77, 4528–4543.
to oxa-di-p-methane product 12, instead a complex mixture was
obtained. This is presumably due to the presence of an additional
carbonyl group which can induce competing photochemical reac-
tions. Therefore, the compound 12 was prepared by Wacker oxida-
tion of 11 (Scheme 4). Structures of compounds 11 and 12 were
deduced from their spectral features. Thus, the IR spectrum of 11
displayed the absorption band at 1721 cmÀ1 for the carbonyl
group. The 1H NMR (400 MHz, CDCl3) of 11 displayed signals at d
5.78–5.65 (m, 1H) and 5.06–5.00 (m, 2H) for three olefinic protons.
The methylene protons in the tetrahydrofuran ring showed signals
at d 4.17 (part of an AB system, J = 8.6 Hz, 1H), 3.78 (part of an AB
system, J = 8.6 Hz, 1H), and 3.64–3.50 (m, 2H). The methyl protons
appeared at d 1.05 (s, 3H). Other protons showed signals at d
3.25–3.14 (m, 1H), 2.48–2.37 (m, 1H), 2.36–2.28 (m, 1H),
2.27–2.18 (m, 2H), 2.16–2.11 (m, 1H), 2.06–1.96 (m, 1H) and
1.33 (triplet with structure, J = 12.8 Hz, 1H). 13C NMR (100 MHz,
CDCl3) of compound 11 showed a signal at d 216.4 for the carbonyl
group. Olefinic carbons appeared at d 133.3 and 118.1. In addition,
signals were displayed at d 68.7, 65.6, 63.8, 63.1, 56.8, 45.1, 37.4,
34.8, 30.8, 22.2 and 16.9 for other carbons.
6. (a) Singh, V. Acc. Chem. Res. 1999, 32, 324–333; (b) Singh, V.; Pal, S.; Mobin, S.
M. J. Org. Chem. 2006, 71, 3014–3025; (c) Singh, V.; Chandra, G.; Mobin, S. M.
Synthesis 2008, 2719–2728; (d) Singh, V.; Sahu, P. K.; Sahu, B. C.; Mobin, S. M. J.
Org. Chem. 2009, 74, 6092–6104; (e) Singh, V.; Bhalerao, P.; Sahu, B. C.; Mobin,
S. M. Tetrahedron 2013, 69, 137–146; (f) Singh, V. Synlett 2013, 2641–2659.
7. (a) Pfeiffer, M. W.; Phillips, A. J. J. Am. Chem. Soc. 2005, 127, 5334–5335; (b)
Toyota, M.; Asano, T.; Ihara, M. Org. Lett. 2005, 7, 3929–3932; (c) Paquin, J. F.;
Defieber, C.; Stephenson, C. R. J.; Carreira, E. M. J. Am. Chem. Soc. 2005, 127,
10850–10851; (d) Cook, S. P.; Gaul, C.; Danishefsky, S. J. Tetrahedron Lett. 2005,
46, 843–847.
8. (a) Banwell, M. G.; Edwards, A. J.; Harfoot, G. H.; Jolliffe, K. A. Tetrahedron 2004,
60, 535–547; (b) Srikrishna, A.; Satyanarayana, G. Org. Lett. 2004, 6, 2337–
2339; (c) Njardarson, J. T.; Mc Donald, I. M.; Spiegel, D. A.; Inoue, M.; Wood, J. L.
Org. Lett. 2001, 3, 2435–2438.
9. (a) Rakotonandrasana, O. L.; Raharinjato, F. H.; Rajaonarivelo, M.; Dumontet, V.;
Martin, M. T.; Bignon, J.; Rasoanaivo, P. J. Nat. Prod. 2010, 73, 1730–1733; (b) Li,
S. H.; Wang, J.; Niu, X.-M.; Shen, Y. H.; Zhang, H. J.; Sun, H. D.; Li, M.; Tian, Q. E.;
Lu, Y.; Cao, P.; Zheng, Q. T. Org. Lett. 2004, 6, 4327–4330; (c) Hill, R. A.;
Sutherland, A. Nat. Prod. Rep. 2009, 26, 151–154; (d) Liu, M.; Lin, S.; Gan, M.;
Chen, M.; Li, L.; Wang, S.; Zi, J.; Fan, X.; Liu, Y.; Si, Y.; Yang, Y.; Chen, X.; Shi, J.
Org. Lett. 2012, 14, 1004–1007; (e) Morita, H.; Ishioka, N.; Takatsu, H.; Iizuka, T.;
Kobayashi, J. J. Nat. Prod. 2006, 69, 418–420; (f) Kobayashi, J.; Kubota, T. Nat.
Prod. Rep. 2009, 26, 936–962.
10. (a) Takasu, K.; Mizutani, S.; Ihara, M. J. Org. Chem. 2002, 67, 2881–2884; (b)
Srikrishna, A.; Ravi Kumar, P. Tetrahedron Lett. 2002, 43, 1109–1111; (c)
Srikrishna, A.; Reddy, T. J. J. Chem. Soc., Perkin Trans. 1 1998, 2137–2144; (d)
Kalliappan, K.; Subbarao, G. S. R. J. Chem. Soc., Perkin Trans. 1 1997, 3387–3392;
(e) Banwell, M. G.; Dupuche, J. R. J. Chem. Soc., Chem. Commun. 1996, 869–870;
(f) Evans, D. A.; Scott, W. L.; Truesdale, L. K. Tetrahedron Lett. 1972, 13, 121–124.
11. Suzuki, M.; Sugiyama, T.; Watanabe, M.; Murayama, T.; Yamashita, K. Agric.
Biol. Chem. 1987, 51, 1121.
Conclusion
We have described a tandem oxidative dearomatization–in-
tramolecular cycloaddition in spiroepoxycyclohexa-2,4-dienone
bearing olefinic tether at C-5 that provided an efficient route to tri-
cyclic system containing bicyclo[2.2.2]octane framework endowed
12. (a) Singh, V.; Thomas, B. J. Chem. Soc., Chem. Commun. 1992, 1211–1213; (b)
Singh, V.; Thomas, B. J. Org. Chem. 1997, 62, 5310–5320.
with a b,c-enone chromophore. Manipulation of adduct in ground
13. (a) Waring, A. J. In Advances in Alicyclic Chemistry; Hart, H., Karabatsos, G., Eds.;
Academic Press: New York, 1966; vol. 1, pp 129–256; (b) Adler, E.; Holmberg,
K. Acta Chem. Scand. Ser. B 1974, 28, 465–477; (c) Singh, V.; Sahu, B. C.; Bansal,
V.; Mobin, S. M. Org. Biomol. Chem. 2010, 8, 4472–4481.
state followed by photochemical reaction led to oxa-polyquinanes.
The work presented herein further demonstrates synthetic poten-
tial of oxidative dearomatization of o-hydroxymethylphenols and
cycloaddition of spiroepoxycyclohexa-2,4-dienones and consti-
tutes a good example of efficient creation of structural, functional
and stereochemical complexity from simple aromatics.
14. Data for compound 6: IR (KBr)
m .
max: 1734, 1658 cmÀ1 1H NMR (400 MHz,
CDCl3): d 6.65 (doublet with structure, J = 8.3 Hz, 1H), 6.23 (dd, J1 = 8.3 Hz,
J2 = 7.0 Hz, 1H), 4.08 (merged dd, J1 = J2 = 7.6 Hz, 1H), 3.76 (s, 2H), 3.62 (dd,
J1 = 12.1 Hz, J2 = 7.6 Hz, 1H), 3.49–3.45 (m, 1H), 2.94 (part of an AB system,
J = 5.8 Hz, 1H), 2.79 (part of an AB system, J = 5.8 Hz, 1H), 2.39–2.27 (m, 1H),
2.17–2.03 (m, 1H), 1.78 (dd, J1 = 13.5 Hz, J2 = 7.5 Hz, 1H). 13C NMR (100 MHz,
CDCl3): d 204.2, 137.8, 127.4, 70.4, 67.2, 56.6, 52.1, 47.9, 47.5, 44.9, 22.3. HRMS
(ESI-MS) (m/z): found 193.0859 (M+H)+; calcd for C11H13O3: 193.0865. Crystal
data of compound 6: C11H12O3, M = 192.21, Monoclinic, space group P 1 21/c 1,
Acknowledgments
V.S. is grateful to the Department of Science and Technology
New Delhi for a J.C. Bose National Fellowship (SR/S2/JCB-34/
2009) and IIT Bombay for a Chair Professorship. B.D. is thankful
to the Council of Scientific and Industrial Research, New Delhi
and IIT Bombay for a research fellowship. We are thankful to D.
Mahtre for X-ray crystal structure determination.
a = 11.7115 (10) Å, b = 7.210 (6) Å, c = 10.734 (9) Å,
a = 90°, b = 99.632(17)°,
c
= 90°, V = 893.6 (11) Å3, Dc = 1.429 Mg mÀ3
, Z = 4, F(000) = 408, size:
0.36 Â 0.28 Â 0.10 mm3, wavelength = 0.71075 Å, GoF = 1.073, absorption
coefficient = 0.104 mmÀ1
,
total/unique
reflections = 6588/1646
[R(int) = 0.0811], T = 100 (2) K,
R1 = 0.0440, wR2 = 0.1166,
h
range = 3.33–25.45°, Final R[I > 2s(I)]:
R
(all data): R1 = 0.0500, wR2 = 0.1215.
Crystallographic data has been deposited with Cambridge Crystallographic
data Centre, CCDC no. 1039306. Copy of the data can be obtained, free of
charge, on application to CCDC. E-mail. Deposit@ccdc.cam.ac.UK..
Supplementary data
15. (a) Nicolaou, K. C.; Toh, Q. Y.; Chen, D. Y. K. J. Am. Chem. Soc. 2008, 130, 11292–
11293; (b) Singh, V.; Das, B.; Mobin, S. M. Synlett 2013, 1583–1587.
16. (a) Stork, G.; Baine, N. H. Tetrahedron Lett. 1985, 26, 5927–5930; (b) Paquette, L.
A.; Choon, S. R.; Silvestri, T. W. Tetrahedron 1989, 45, 3099–3106.
17. (a) Schuster, D. I. In Rearrangement in Ground and Excited States; de Mayo, P.,
Ed.; Academic Press: New York, 1980; Vol. 3, pp 167–279; (b) Demuth, M.;
Hisken, W. Angew. Chem., Int. Ed. 1985, 24, 973–975; (c) Zimmerman, H. E.;
Armesto, D. Chem. Rev. 1996, 96, 3065–3112.
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.tetlet.2015.02.113.
References and notes
18. (a) Singh, V. In CRC Handbook Organic Photochemistry and Photobiology;
Horspool, W. M., Lenci, F., Eds.; CRC: Boca Raton, FL, 2004; Vol. 3, Chapters
78 and 79; (b) Maiti, B. C.; Lahiri, S. Tetrahedron 1997, 53, 13053–13062; (c)
Maiti, B. C.; Singh, R.; Lahiri, S. J. Photochem. Photobiol., A 1995, 91, 27–32; (d)
McClure, C. K.; Kiessling, A.; Link, J. S. Org. Lett. 2003, 5, 3811–3813.
19. (a) Singh, V.; Sahu, P. K.; Singh, R. B.; Mobin, S. M. J. Org. Chem. 2007, 72, 10155–
10165; (b) Bon, D. J. Y.; Banwell, M. G.; Cade, I. A.; Willis, A. C. Tetrahedron
2011, 67, 8348–8352; (c) Goodell, J. R.; Poole, J. L.; Beeler, A. B.; Aube, J.; Porco,
J. A., Jr. J. Org. Chem. 2011, 76, 9792–9800.
20. (a) Jamison, T. F.; Shambayati, S.; Crowe, W. E.; Schreiber, S. L. J. Am. Chem. Soc.
1997, 119, 4353–4363; (b) Pass, M.; Abu-Rabie, S.; Baxter, A.; Conroy, R.; Coote,
S. J.; Craven, A. P.; Finch, H.; Hindley, S.; Kelly, H. A.; Lowdon, A. W.; McDonald,
E.; Mitchell, W. L.; Pegg, N. A.; Procopiou, P. A.; Ramsden, N. G.; Thomas, R.;
Walker, D. A.; Watson, N. S.; Jhoti, H.; Mooney, C. J.; Tang, C. M.; Thomas, P. J.;
Parry, S.; Patel, C. Bioorg. Med. Chem. Lett. 1999, 9, 1657–1662; (c) Bailey, W. F.;
Khanokar, A. D.; Gavaskar, K. V. J. Am. Chem. Soc. 1992, 114, 8053–8060; (d)
Coates, R. M.; Ho, Z.; Klobus, M.; Wilson, S. R. J. Am. Chem. Soc. 1996, 118, 9249–
9254.
1. (a) Nicolaou, K. C.; Chen, Jason S. Chem. Soc. Rev. 2009, 38, 2993–3009; (b)
Newhouse, T.; Baran, P. S.; Hoffmann, R. W. Chem. Soc. Rev. 2009, 38, 3010–
3021; (c) Poulin, J.; Grise-Bard, C. M.; Barriault, L. Chem. Soc. Rev. 2009, 38,
3092–3101.
2. (a) Umland, K. D.; Kirsch, S. F. Synlett 2013, 1471–1484; (b) Tietze, L. F.;
Brasche, G.; Gericke, K. M. Domino Reactions in Organic Synthesis; Wiley-VCH:
Weinheim, Germany, 2006; (c) Tietze, L. F. Chem. Rev. 1996, 96, 115–136.
3. (a) Roche, S. P.; Porco, J. A., Jr. Angew. Chem., Int. Ed. 2011, 50, 4068–4093; (b)
Pouysegu, L.; Deffieux, D.; Quideau, S. Tetrahedron 2010, 66, 2235–2261; (c)
Quideau, S.; Pouysegu, L.; Deffieux, D. Synlett 2008, 467–495; (d) Liao, C. C. Pure
Appl. Chem. 2005, 77, 1211–1234; (e) Magdziak, D.; Meek, S. J.; Pettus, T. R. R.
Chem. Rev. 2004, 104, 1383–1429.
4. (a) Yang, Q.; Njardarson, J. T.; Draghici, C.; Li, F. Angew. Chem., Int. Ed. 2013, 52,
8648–8651; (b) Varghese, V.; Hudlicky, T. Angew. Chem., Int. Ed. 2014, 53, 4355–
4358; (c) Qingliang, Y.; Cristian, D.; Njardarson, J. T.; Fang, L.; Brandon, S. R.;
Das, P. Org. Biomol. Chem. 2014, 12, 330–344.
5. (a) Mehta, G.; Maity, P. Tetrahedron Lett. 2008, 49, 318–322; (b) Morton, J. G.
M.; Draghici, C.; Kwon, L. D.; Njardarson, J. T. Org. Lett. 2009, 11, 4492–4495; (c)