A novel reactivity of SeO(2) with 1,3-dienes: formation of syn 1,2- and 1,4-diols via a facile C-Se bond oxidation.

Article abstract of DOI:10.1021/ol016462e

[reaction: see text] A novel reaction between 1,3-dienes and selenium dioxide to give syn 1,2- and 1,4-diol cyclic selenites was studied in detail. This study indicates that an initial concerted [4 + 2] cycloaddition followed by a stereospecific carbon-se

Full text of DOI:10.1021/ol016462e

ORGANIC
LETTERS
2001
Vol. 3, No. 20
3161-3163
A Novel Reactivity of SeO with
2
1,3-Dienes: Formation of syn 1,2- and
1,4-Diols via a Facile C−Se Bond
Oxidation
Truc M. Nguyen and Daesung Lee*
Department of Chemistry, UniVersity of Wisconsin-Madison,
Madison, Wisconsin 53706
dlee@chem.wisc.edu
Received July 19, 2001
ABSTRACT
A novel reaction between 1,3-dienes and selenium dioxide to give syn 1,2- and 1,4-diol cyclic selenites was studied in detail. This study
indicates that an initial concerted [4 + 2] cycloaddition followed by a stereospecific carbon−selenium bond oxidation is involved in this
unprecedented syn dihydroxy addition reaction mediated by selenium dioxide.
The formation of a diol from an alkene is an important
transformation in organic chemistry.1 Usually, the syn
addition of dihydroxy groups is achieved by OsO4,2 RuO4,3
and MnO4,4 whereas anti addition is brought about by other
oxides such as SeO25 and WO3.6 In our investigations of the
reaction between SeO2 and 1,3-dienes, a novel reactivity
profile of SeO2 was observed, affording syn 1,2- and 1,4-
diols and selenophene. Treatment of diene 1, containing a
carbonyl group at the C-1 position, with SeO2 led to the
formation of selenophene 2, whereas the analogous diene 3,
containing a TBS-ether, yielded 1,4-diol cyclic selenite 4
and 1,2-diol cyclic selenite 5 (Scheme 1). Notably, the
Scheme 1
(1) (a) Haines, A. H. In ComprehensiVe Organic Synthesis; Trost, B.
M., Fleming, I., Eds.; Pergamon: Oxford, 1991; Vol. 7, pp 437-448. (b)
Burnett, J. F. Pure Appl. Chem. 1981, 53, 305-321.
(2) Kolb, H. C.; VanNieuwenhze, M. S.; Sharpless, K. B. Chem. ReV.
1994, 94, 2483-2547.
(3) Shing, T. K. M.; Tam, E. K. W.; Tai, V. W.-F.; Chung, I. H. F.;
Jiang, Q. Chem. Eur. J. 1996, 2, 50-57.
(4) (a) Larsen, S. D.; Monti, S. A. J. Am. Chem. Soc. 1977, 99, 8015-
8020. (b) Lee, D. G.; Chang, V. S. J. Org. Chem. 1978, 43, 1532-1536.
(c) Wolfe, S.; Ingold, C. F.; Lemieux, R. U. J. Am. Chem. Soc. 1981, 103,
938-939.
conversion of 3 to 4 involves an unprecedented direct
oxidation of a C-Se bond to a C-O bond, a transformation
known to be difficult.7 In this account, we elucidate the nature
(5) (a) Knothe, G.; Glass, R. S.; Schroeder, T. B.; Bagby, M. O.;
Weisleder, D. Synthesis 1997, 57-60. (b) Sonoda, N.; Tsutsumi, S. Bull.
Chem. Soc. Jpn. 1965, 38, 958-961. (c) Itakura, J.; Tanaka, H.; Ito, H.
Bull. Chem. Soc. Jpn. 1969, 42, 1604-1608.
(7) Discussions in Supporting Information of J. Am. Chem. Soc. 1998,
120, 6844-6845.
(6) Mugdan, M.; Young, D. P. J. Chem. Soc. 1949, 2988-3000.
10.1021/ol016462e CCC: $20.00 © 2001 American Chemical Society
Published on Web 09/06/2001

of the intermediates involved in this novel syn dihydroxy-
lation reaction by SeO2 and the stereospecificity of the C-Se
bond oxidation.
experiment showing a NOE between the H-1 and H-4
protons.
The reaction of phenyl- and tert-butyl-substituted cis
dienes 9 and 10 with SeO2 was also studied (Scheme 2).
The formation of the selenino lactone 11 from 9, with an
appreciable amount of isomerization of 9 to the trans isomer
3, was detected by NMR. The selenino lactone structure of
Despite the fact that we have not detected the selenino
lactone 6 from the reaction between 3 and SeO2, we
hypothesized the existence of 6, which would then lead to
the cyclic selenite 4.8 To test this hypothesis and to probe
the mechanistic aspects of the transformation from the
selenino lactone to the cyclic selenite, tert-butyl-substituted
trans-1,3-diene 7 and phenyl- and tert-butyl-substituted cis
isomers 9 and 109 were prepared and their reactions with
SeO2 were monitered by NMR spectroscopy (Scheme 2).10
1
11 is supported by H NMR (δ 4.12, dt, J ) 4.4, 2.6 Hz,
H-1; 5.80, q, J ) 3.7 Hz, H-3; 5.81, t, J ) 3.9 Hz, H-4),
77Se NMR (δ 1218.3, dd, J ) 26, 15 Hz), and 1JSe-C1 ) 87
Hz. It was evident from the NMR monitoring that the cis
isomer 9 reacts with SeO2 faster than the trans isomer 3. A
quantitative conversion of diene 10 to 12 was also observed
under identical conditions, albeit, at a much slower rate than
the trans isomer 7. The characteristic resonances of adduct
Scheme 2
1
12, H NMR (δ 3.71, dt, J ) 4.2, 3.1 Hz, H-1; 5.57, t, J )
3.1 Hz, H-3; 4.31, t, J ) 3.2 Hz, H-4), 77Se NMR (δ 1195.8,
1
dd, J ) 26, 15 Hz), and JSe-C1 ) 87 Hz, are close to but
different from those of the corresponding diastereomer 8,
which confirms the stereospecific nature of the addition
reaction between dienes and SeO2.
Once we confirmed the existence of the purported selenino
lactones 8, 11, and 12, we studied the reactivity and the fate
of these intermediates by NMR, followed by the isolation
of the final products (Scheme 3). To exclude the possibility
Scheme 3
The clean conversion of the tert-butyl-substituted trans
diene 7 to the corresponding selenino lactone 8 was observed
within 2 h in CDCl3. However, the purported selenino lactone
6 was not detected by the analogous experiment involving
diene 3. The structure of selenino lactone 8 is consistent with
1
the H NMR (δ 3.61, dd, J ) 8.8, 2.4 Hz, H-1; 5.94, dd, J
) 5.0, 2.8 Hz, H-3; 4.11, dd, J ) 4.8, 1.0 Hz, H-4) and 77Se
NMR (δ 1228.6, d, J ) 13 Hz) resonances. This disparity
indicates that the phenyl group may facilitate the conversion
of 6 to 4, whereby the accumulation of 6 to any detectable
concentration was prohibited. The identity of 8 was further
confirmed by the scrutiny of C-H and C-C connectivity
from COSY, gradient HSQC, and carbon-observed proton-
decoupled (13C{1H}) NMR experiments. The signal of the
C-1 carbon was observed to be coupled to 77Se (J ) 93 Hz),
the value of which is consistent with the coupling constant
for the typical C-Se one-bond coupling (1JSe-C > 45 Hz).11
The stereochemistry of 8 was confirmed by a NOESY
(8) Mock, W. L.; McCausland, J. H. Tetrahedron Lett. 1968, 3, 391-
392.
(9) A degassed benzene solution of 1 was irradiated for 3 h with a 450-W
Hanovia medium-pressure mercury lamp equipped with a 0.5 M CuSO4
filter solution. The cis isomer was isolated at 60% conversion in 50% yield
and was converted to 9 via reduction followed by silyl protection; 10 was
similarly prepared (see Supporting Information).
of any acid-catalyzed processes, the selenino lactones 8, 11,
and 12 were treated with triethylamine or pyridine. Unfor-
tunately, under these conditions the selenino lactones un-
derwent cycloreversion to the starting 1,3-dienes and SeO2.12
In the absence of excess SeO2 the selenino lactones 8, 11,
and 12 are stable for several days in CDCl3, whereas with
(10) 77Se NMR spectra were referenced to external SeMe2 in CDCl3;
see: Luthra, N. P.; Odom, J. D. In The Chemistry of Organic Selenium
and Tellurium Compounds; Patai, S., Rappoport, Z. Eds.; Wiley: New York,
1986; Vol. 1, pp 189-241. A mixture of diene (3, 7, 9, 10) and excess
SeO2 in CDCl3 was vigorously stirred, filtered through a cotton plug to
remove excess SeO2, and monitored by NMR spectroscopy.
(11) McFarlane, H. C. E.; McFarlane, W. In NMR of Newly Accessible
Nuclei, Vol. 2; Laszlo, P. Ed.; Academic Press: New York, 1983; pp 275-
299 and references therein.
(12) The addition of triethylamine to 13, independently generated from
the reaction of 1,4-diol 15 with SeO2, resulted in the ring opening of the
cyclic selenite.
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Org. Lett., Vol. 3, No. 20, 2001

an excess amount of SeO2 these adducts transformed to cyclic
selenites 13 (77Se NMR δ 1309.3, t, J ) 9 Hz), 19 (2
diastereomers, 77Se NMR δ 1346.5, s and δ 1341.1, t, J )
4 Hz), and 20 (77Se NMR δ 1309.9, t, J ) 9 Hz),
respectively.13 The existence of these cyclic selenites, includ-
ing 4 (77Se NMR δ 1311.6, t, J ) 9 Hz) were further
confirmed by isolation of the corresponding 1,4-diols, by
SiO2 chromatography, followed by their regeneration from
the reaction of the diols with SeO2.14 Remarkably, it was
observed that cyclic selenites 4 and 13 stereospecifically
rearranged at ambient temperature to selenites 5 (2 diaster-
eomers, 77Se NMR δ 1466.0, d, J ) 16 Hz and δ 1453.8, s)
and 16 (2 diastereomers, δ 1463.4, d, J ) 15 Hz, δ 1453.7,
s), respectively. The existence of 5 and 16 was inferred from
the 77Se NMR and the isolation of 1,2-diols 17 and 18.5a
The rate of formation of 5 is faster than that of 16,
presumably as a result of the thermodynamic driving force
for the formation of a styrene moiety in 5.15
Table 1. Substituent Effect of syn Dihydroxylation of
1,3-Dienes Mediated by SeO2
Similarly, the reaction of cis dienes 9 and 10 with SeO2
initially resulted in adducts 11 and 12 (Scheme 2), which
smoothly transformed to the 1,4-cyclic selenites 19 and 20,
respectively (Scheme 3).16 Unlike the 1,4-cyclic selenites 4
and 13, derived from the trans dienes, 19 and 20 rearranged
to the regioisomeric 1,2-cyclic selenites 23 (77Se NMR δ
1428.4, s) and 24 (77Se NMR δ 1414.5, s), eventually
affording diols 25 and 26.17,18 The other regioisomers 5′ and
16′ were not detected. We assumed the generation of the cis
double bond of 5′ and 16′ from 19 and 20 is highly
unfavorable compared to the alternative rearrangement
affording the endocyclic olefins 23 and 24.
On the basis of these results, we conclude that the initial
addition of SeO2 to form the selenino lactones (6, 8, 11, 12)
is a concerted [4 + 2] cycloaddition. These selenino lactones
then undergo a stereospecific C-Se bond oxidation, leading
to the 1,4-diol cyclic selenites (4, 13, 19, 20), which undergo
rearrangement to the 1,2-diol cyclic selenites (5, 16, 23, 24).
To the best of our knowledge this is the first example in
which a selenino lactone undergoes a facile C-Se bond
oxidation, without the involvement of the well-known [2,3]
sigmatropic rearrangement, to form 1,2-diol cyclic selenite
via 1,4-diol cyclic selenite as a penultimate intermediate.19,20
The substituent effect of this syn dihydroxylation of 1,3-
dienes was examined (Table 1). The reaction of the parent
trans phenyl-substituted diene 3 yielded diols 14 (50%) and
17 (10%) at 25 °C (entry 1). At 80 °C, only 1,2-diol 17 was
isolated in 66% (entry 2). The 2,6-dichlorophenyl-substituted
diene 27a afforded diols 28a (45%) and 29a (15%) with
comparable efficiency, although longer reaction times are
required (25 °C, 96 h), presumably because of the electron-
withdrawing nature of the dichloro substituents (entry 3).
Similarly, 1,2-diol 29a (61%) was obtained with minor 1,4-
diol 28a (5%) at 80 °C (entry 4). The cinnamyl derivative
27b afforded exclusively 1,2-diol 29b (41%) without 1,4-
diol 28b, along with tetraol 30 (20%) (entry 5). 4-Dimethyl-
aminophenyl-substituted diene 27c did not lead to any diols;
instead, the 1,4-diketone 31 was isolated (63%) (entry 6).
In summary, we have discovered a novel syn dihydroxy-
lation of 1,3-dienes with SeO2, which involves a [4 + 2]
cycloaddition followed by C-Se bond oxidation. The
efficiency of this process is a function of the stereoelectronic
nature of the substituents on the diene. Another finding is
the sterospecific conversion of a 2-alkene-1,4-diol moiety
to a 3-alkene-1,2-diol moiety by SeO2 under mild conditions.
The usefulness of these transformations is currently under
study, and the result will be reported in due course.
Acknowledgment. D.L. gratefully acknowledges the
University of Wisconsin-Madison for startup research fund-
ing and the Camille and Henry Dreyfus Foundation for a
New Faculty Award. NMR support through grants NSF
CHE-8813550, NIH 1 S10 RR04981-01, and NSF CHE-
9629688 is greatly appreciated. The authors thank Profs.
Reich, Gellman, and Kiessling for helpful discussions, Dr.
Stringfellow and Dr. Fry for NMR assistance, Dr. Guzei for
X-ray structural analyses, and Dr. Vestling for mass spectral
information.
(13) In the conditions for the rearrangement of 13 to 16, 1,4-diketone
32 and the corresponding hydroxyketone 33 were obtained (see Supporting
Information).
(14) (a) Denney, D. B.; Denny, D. Z.; Hammond, P, J.; Hsu, Y. F. J.
Am. Chem. Soc. 1981, 103, 2340-2347.
(15) The stereochemistry of the C-1 and C-2 positions of 1,2-diol 17
was confirmed by an X-ray analysis of the corresponding acetonide.
(16) The minor isomerization of cis-diene 9 induced by SeO2 to trans-
dienes 3 resulted in the formations of diols 14, 17, 21, and 25.
(17) Interestingly, the reaction of 21 with excess SeO2 at 40 °C did not
lead to any expected 1,2-diol 25, and instead 1,2-diol 17 was isolated. It is
believed that under the reaction conditions 19 rearranged to 5 via a benzylic
cation.
(18) Diol 26 was independently generated by reaction of cis diene 10
with OsO4/NMO at 50 °C.
(19) Sharpless, K. B.; Singer, S. P. J. Org. Chem. 1976, 41, 2504-2506.
(20) The reaction of a purified selenino lactone 12 with mCPBA in CDCl3
directly produced 1,2-cyclic selenite 24. The 1,4-cyclic selenite 20 was not
observed.
Supporting Information Available: Characterization
data for all new compounds. This material is available free
of charge via the Internet at http://pubs.acs.org.
OL016462E
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